BS REPORTS

EDTMP is also one of the most

commonly used scale and corrosion

inhibitors in circulating cooling water

systems. It forms stable complexes with

many ions, Ca(II), Mg(II), Fe(II), Zn(II),

Al(III), Fe(III) etc., and the chelators are

often multi-ring.

STUDIES ON APPLICATION OF ANION EXCHANGERS IN REMOVAL OF METAL COMPLEXES WITH EDTMP

Dorota KOŁODYŃSKA, Marzena GĘCA, Zbigniew HUBICKI

DEPARTMENT OF INORGANIC CHEMISTRY

For many years complexing agents have received increasing attention among

researchers. They are widely used in many industries, moreover, they have also

become an integral part of everyday human life. These compounds are capable of

chelating with metal ions to create connections in the form of complexes. Besides

the positive aspects of the use of complexing agents in our lives, there are some

negative ones – the complexing agents affect the bioavailability of the metal ions,

disturbing their natural speciation, which may cause their release from sewage

sludge. However, the largest concern is connected with the lack of their

biodegradability and persistence in the environment [1].

In the group of complexing agents, aminopolycarboxylic acids (APCA),

aminopolyphosphonic acids (APPA) and hydroxoacids (HA) should be mentioned.

They are characterized by good pH, temperature and pressure stability, high water

solubility, high density of functional groups, good compatibility with other

ingredients of formulations.

Phosphonates belong to the group of complexing agents which contain one or

more phosphonic acid groups –PO(OH)2 [2]. The most important in industry and

analytical chemistry are aminopolyphosphonic complexones, which are regarded as

analogues of commonly used chelating agents such as EDTA

(ethylenediaminetetracetic acid) or NTA (nitrilotriacetic acid). In this group

EDTMP (1,2-diaminoethanetetrakis(methylenephosphonic acid)) should be

mentioned.

The main tasks of the presented paper were (1) to test the commercially

available anion exchangers towards such species as Cu(II), Zn(II), Pb(II) and Cd(II)

complexes with EDTMP and (2) to select the anion exchanger that showed the best

performance towards the above-mentioned species and (3) characterize their

structure and physicochemical properties as far as the anionic species sorption is

concerned.

1,2-diaminoethanetetrakis(methylenephosphonic acid) EDTMP (other

abbreviations EDTP, EDTPH, ENTMP, EDTMPO, EDTMPA) is formed by

ethylenediamine, formaldehyde and phosphorus trichloride. Its structure can be

presented as:

EDTMP is effective in inhibiting calcium carbonate scale formation, iron

oxide and hydrated calcium sulfate scale, and the largest extent in the stable

supersaturated solution of calcium sulfate. The loose scale does not decompose at

473 K, therefore, EDTMP is more applicable for the treatment of low pressure

boiler furnace.

Investigations were carried out using the static and dynamic methods, based on

which adsorption parameters were calculated. The exemplary breakthroughs as well

as the mass (Dg) and volume (Dv) distribution coefficients as well as the working

(Cw) and total (Ct) ion exchange capacities (mg/cm3) for Cu(II), Zn(II), Pb(II) and

Cd(II) in the presence of EDTMP on Lewatit MonoPlus M 500 in the M(II)-

EDTMP=1:2 system at pH 9.0 are presented below:

During research it was found that phase contact time, pH, temperature and

initial metal concentration influence the effectiveness of heavy metal complexes

sorption in the presence of EDTMP on Lewatit MonoPlus M 500 and Lewatit MP

62. Batch equilibrium was relatively fast and it reached equilibrium after about 60

min of contact. The ion exchange process, which is pH dependent showed

maximum removal of Cu(II) at pH 9.0 (initial concentration of 1× 10-3

M) only for

the strongly basic anion exchanger. It was shown that temperature slightly affects

sorption efficiency. The pH dependence of ion exchange may suggest that the metal

ions are adsorbed according to an ion exchange mechanism.

References:

[1] A.T. Stone, M.A. Knight, B. Nowack, Speciation and chemical reactions of phosphonates chelating agents in aqueous media, in: Chemicals in the

Environment, R.L. Lipnick, R.P. Mason, M.L.Phillips, Ch.U. Pittman, Jr, (eds),

ACS Symposium Series 806, American Chemical Society, Washington,

[2] B. Nowack, J.M. VanBriesen, Chelating agents in environment, in: Biogeochemistry of chelating agents, B. Nowack, J.M. VanBriesen(eds.), ACS

Symposium series 910, pp. 1-18.

System

/Ion exchanger

D

g

D

v

C

w

C

t

Lewatit MonoPlus M 500

Cu(II)-

EDTMP=1:2

2

16.7

7

2.0

0

.002

0

.004

Zn(II)-

EDTMP=1:2

2

4.2

8

.0

0

.003

0

.005

Pb(II)-

EDTMP=1:2

1

90.6

6

3.3

0

.007

0

.013

Cd(II)-

EDTMP=1:2

4

98.4

1

65.6

0

.014

0

.018

INVESTIGATION OF REDUCTION MECHANISM OF CHROMIUM

(VI) IONS IN QUATERNARY AMMONIUM SALT EXTRACTION

PROCESS

Zbigniew HUBICKI and Grzegorz WÓJCIK

DEPARTMENT OF INORGANIC CHEMISTRY

Chromium(VI) is more toxic than chromium(III) due to its toxic effects on

biological systems: nasal septum, asthma, bronchitis, pneumonia, inflamation of the

larynx and liver, skin allergies, dermatitis which can occur after inhalation or skin

contacts with chromium(VI) compounds. For this reason large amounts of

chromium(VI) must be reduced to the safe level. The elimination of toxic and

hazardous chemical substances such as chromium (VI) from waste effluents is a

major concern worldwide. Among all heavy metals, copper, chromium and zinc

ingestion beyond permissible quantities causes various chronic disorders in human

beings [1].The aim of these studies was to investigate of extraction mechanism of

chromium(VI) ions from water solution in the pH range from 1 to 7 by using

Aliquat 128 in toluene. Aliquate 128 is methyltrioctylammonium chloride and was

supplied by Aldrich.

Fig. 1. Molecular structure of Aliquat 128

All experiments were carried out at ambient temperature. Aqueous solution

containing a known amount of Cr (VI) (100ppm) was mixed with 0.1% of Aliquat

128 diluted with toluene at an organic/aqueous (O/A) ratio of 1:1 in a separatory

funnel. The aqueous layer was analyzed for remaining Cr by AAS and Cr(VI)

spectrophotometrically with diphenylcarbazide.

Experimental result (Fig. 2.) showed that the extraction equilibrium takes place at

about 5min.

In acidic medium (pH < 1) Cr (VI) ion exists partly as H2CrO4. At pH between 2

and 6 there is an equilibrium between Cr2O72−

and HCrO4- ionic species and under

alkaline conditions (pH > 8) it exists predominantly as chromate anion[2]. Aliquat

128 shows the maximum extraction efficiency (100%) for the uptake of Cr (VI) at

pH of 1.5. With increase in pH to 3.5, and 7 the extraction efficiency decreases to

90 and 50%, respectively.

The extraction equilibrium of Cr(VI) by Aliquat 128 can be represented

stoichiometrically by the following equations:

R1(R2)3N+Cl

- + HCrO4

- ⇌ R1(R2)3N

+HCrO4

- + Cl

-

2R1(R2)3N+Cl

- + Cr2O7

2- ⇌ (R1(R2)3N

+)2 Cr2O7

2- + 2Cl

-

2R1(R2)3N+Cl

- + CrO4

2- ⇌ (R1(R2)3N

+)2CrO4

2- + 2Cl

-

Fig. 2. Effect of phase contact time on values of extraction factor for Cr(VI) ions on

Aliquat 128 in pH range 1.5-7.

The investigations of chromium(III) and(VI) speciation allowed to notice that

chromium(VI) is reduced to chromium(III) ions at pH 1.5. The reduced

chromium(III) ions are not retained by Aliquate 128 organic phase but are

transferred from internal to aqueous solution. Similar observation during sorption of

chromium (VI) ions on strongly basic anion exchanger were reported[3,4].

The metal loaded solvent was stripped with alkaline solution of 1M NaOH

+1M NaCl to recover the extracted Cr (VI) by mixing for 5 min.

References:

[1] R.S. Prakasham, J.S. Merrie, R. Sheela, N. Saswathi, S.V. Ramakrisha,

Environmental Pollution 104 (1999) 421–427.

[2] R. Ansari, Acta Chimica Slovenica 53 (2006) 88–94.

[3] G. Wójcik, Z. Hubicki, P. Rusek, Przemysł Chemiczny, 90 (2011) 2153.

[4] G. Wójcik, Z. Hubicki, P. Rusek, Przemysł Chemiczny, 92 (2013) 82.

EVALUATION OF EFFECTIVNESS OF INTERMEDIATE AND

STRONGLY BASIC ANION EXCHANGERS IN REMOVAL OF

DIRECT AND REACTIVE DYES FROM AQUEOUS SOLUTIONS

AND WASTEWATERS

Monika WAWRZKIEWICZ, Zbigniew HUBICKI

DEPARTMENT OF INORGANIC CHEMISTRY

INTRODUCTION

Dyeing is a fundamental operation during the textile fiber processing. This

operation causes the production of more or less coloured wastewaters, depending on

the degree of fixation of the dyes on the substrates, which varies with the nature of

the substances, the desired intensity of coloration, and the application method.1 The

dye bearing effluents are considered to be a very complex and inconsistent mixture

of many pollutants ranging from organic-chlorine based pesticides, alkalis, oils,

detergents, salts of organic and inorganic acids to heavy metals [1-4]. Ion exchange

is a very versatile and effective tool for the treatment of aqueous hazardous wastes.

The role of ion exchange in dye effluents treatment is to reduce the magnitude of

hazardous load by converting them into a form in which they can be reused, leaving

behind a less toxic substance in its place or to facilitate ultimate disposal by

reducing the hydraulic flow of the stream bearing the toxic substance. Another

significant feature of the ion exchange process is that it has the ability to separate as

well as to concentrate pollutants.

The adsorption of the dye C.I. Reactive Black 5 (RB5) and C.I. Direct Blue 71

(DB71) from aqueous solution on the intermediate and strongly basic anion

exchangers (Lewatit MonoPlus MP64, Lewatit MonoPlus MP500 and Lewatit

MonoPlus M500) was investigated in order to identify the ability of these materials

to remove textile dyes from wastewaters. For this purpose a series of batch tests

were carried out as a function of contact time (1 min-24 h), dye concentration (100,

500, 1000 mg/L) and auxiliaries presence (NaCl, Na2SO4, surfactant).

RESULTS AND DISSCUSSION

The most famous adsorption models in linearized form for single-solute

systems are the Langmuir and Freundlich. The experimental data obtained in the

present work were tested with these equations. The Langmuir constants Q0 and b

were calculated from the slope and intercept of the plot Ce/qe vs Ce. The plot log qe

versus log Ce should produce a straight line with the slope 1/n and the intercept of

kF. The applicability of isotherm equations was compared by judging the correlation

coefficients (R2). It was found that the dyes sorption on the intermediate and

strongly basic anion exchange resins were well described by the Langmuir

isotherm. For RB5 dye, the values of the monolayer sorption capacities on Lewatit

MonoPlus MP500, Lewatit MonoPlus MP64 and Lewatit MonoPlus M500 were

found to be 1170.5 mg/g (R2=0.997), 592.8 mg/g (R

2=0.989) and 5.2 mg/g

(R2=0.992), respectively. The intermediate and strongly basic anion exchangers

were characterized by lower affinity for the direct dye. The Q0 values obtained from

the Langmuir model of adsorption were found to be 523.64 mg/g, 420.4 mg/g and

2.02 mg/g for Lewatit MonoPlus MP500, Lewatit MonoPlus MP64 and Lewatit

MonoPlus M500, respectively. Taking the above into account, it can be stated that

not only anion exchangers basicity but also the type of dye play an important role in

sorption processess.

The presence of inorganic salts and surfactant such as NaCl, Na2SO4 and SDS

in the solution during the dye adsorption on the anion exchangers was examined

because these substances are typically present in real wastewaters. The following

systems were studied: 100 mg/L of RB5 or DB71 in 25-100 g/L NaCl or Na2SO4 as

well as 100 mg/L of RB5 or DB71 in 0.1-1.0 g/L SDS. The sorption of the dyes on

Lewatit MonoPlus MP500 was slightly reduced in the presence of both electrolytes.

The amounts of RB5 retained by the strongly basic resin MP500 at equilibrium

dropped from 10 mg/g to 9.3 mg/g and from 10 mg/g to 9.2 mg/g with the

increasing amount of NaCl and Na2SO4, respectively. It is due to a competition

between Cl- and SO4

2- anions and the anionic dye. Direct Blue 71 sorption on the

anion exchangers was not influenced by the presence of NaCl and Na2CO3. No

influence of SDS on the dyes sorption by the anion exchangers was observed.

The strongly basic anion exchanger MP500 proves to be capable of color

removal of reactive dye wastewater providing 89% color removal after only 15 min

of adsorption process and reaching 99.9% color removal after 3 h. This percentage

of color removal attained for the model textile wastewater is very high and suggests

that Lewatit MonoPlus MP500 with very good sorption characteristics could be a

promising adsorbent for real textile wastewaters containing reactive dyes.

The adsorption of the dyes on the anion exchangers followed the pseudo-

second order kinetics.

Dye desorption from Lewatit MonoPlus MP500 was effective using 1 M HCl

in 90% CH3OH.

CONCLUSION

The above results indicate that the anion exchange sorption is promising

treatment for the removal of RB5 dye from aqueous solutions and real textile

streams.

References:

[1] N. Ouazene, A. Lounis, Color. Technol. 127 (2011) 1.

[2] S.T. Ong, Ch.K. Lee, Z. Zainal, Aust. J. Basic& Appl. Sci. 3 (2009) 3408.

[3] C.H. Liu, J.S. Wu, H.C. Chiu, S.Y. Suen, K.H. Chu, Water Res. 41 (2007) 1491.

[4] Z.P. Sandić, A.B. Nastasović, N.P. Jivić-Jovičić, A.D. Milutinović-Nikolić,

D.M. Jovanović, J. Appl. Polym. Sci. 121 (2011) 234.

STUDIES OF SEPARATION AND SORPTION OF METAL IONS ON

THE CHELATING RESIN WITH PARTICULAR CONSIDERATION

OF NOBLE METAL IONS

Anna WOŁOWICZ, Zbigniew HUBICKI,

DEPARTMENT OF INORGANIC CHEMISTRY

The preparation of functionalized polymers containing ion-selective ligands

allows to use sorption technology for the separation and recovery of valuable metals

e.g. noble metal ions, for removal of toxic and base metal ions from environmental

sources, waste materials, metallurgical etc. Nowadays strong efforts are directed on

the development and broader application of the chelating resin of polyacrylate

matrix in water treatment, food processing, purification of drugs, antibiotics and

vitamins, wastewaters treatment, dye removal as well as in recovery, removal,

preconcentration and separation of selected noble metal ions [1-9]

.

The aim of research was to study the possibility of applied the chelating resin

for metal ions separation and sorption from chloride and chloride-nitrate solutions

with particular consideration of noble metal ions. The properties of chelating resin

used in this studies is presented in Table 1. Moreover, the working ion-exchange

capacities as well as the weight and bed distribution coefficients were determined

from the metal ions breakthrough curves. The kinetics, equilibrium and desorption

of loaded metal ions were performed.

Table 1. Characteristics of the ion exchanger.

Description Purolite S-984

Structure Macroporous

Type Weak Base / Chelating

Functional groups polyamine - mixed primary, secondary and

tertiary amines

Ionic form as shipped Free base

Matrix Polyacrylate

Moisture Retention 45 - 55 % Cl- form

Temp. Limit 373 K Cl- form

Total exchange

capacity [eq/cm3]

2.7

Sorption recovery of palladium(II), platinum(IV) and gold(III) from the

chloride and chloride-nitrate(V) solutions on the polyacrylate Purolite S-984 resin

was investigated. The studies showed that Purolite S-984 possesses high affinity for

noble metal ions in both single and tertiary component solutions. Purolite S-984

was found to be the most effective one for the sorption of gold(III) as its

breakthrough capacity and sorption capacity were found to be 0.2125 g/cm3 and

0.3248 g/cm3 respectively in 0.1 M HCl. Decrease of the working ion exchange

capacities with the hydrochloric acid concentration increase can be easily observed.

97.7 % reduction of this capacity was observed for Au(III) and for Pd(II) whereas

for Pt(IV) of 90.6 %. As follows from the kinetic studies, the sorption process is

fast and the time required to reach the system equilibrium is short. The time

required to reached equilibrium by the system is equal to 15 min - 0.1 M HCl; 120

min – 1.0 M HCl; 240 min – 3.0 M HCl, whereas for the HCl-HNO3 solutions this

time is in the range 120-240 min. The increasing effect of competitive sorption with

the increasing chloride ions concentration is observed which results in longer time

required to reach equilibrium in the solutions of higher HCl acid concentration.

The pseudo-second order kinetic equation fits well the experimental results.

Moreover, the changes of experimental conditions contribute to the highest metal

ions removal. The agitation speed effect is observed only at the beginning of the

sorption process until the equilibrium is reached. At 120 гpm agitation speed the

kinetics of Pd(II) sorption is slower, the time required to reach equilibrium is longer

than for 150 and 180 гpm speed of agitation and is equal to 180 min (120 гpm), 60

min (150 гpm) and 30 min (180 гpm), respectively. Then the values of the sorption

capacities are as high as possible and equal to 50 mg/g for all cases. The ion

exchange resin beads size also affect the sorption efficiency of Pd(II) but only at the

beginning of the sorption. With the decrease of the ion exchange resin beads size

the qt values reach higher values. The amount of sorbed Pd(II) increased slightly

with the temperature changes from ambient to higher with the 0-15 min phases

contact time but 313 and 333 K temperatures gave similar results in the whole

phases contact time. The anion exchange resin capacity is high enough - all Pd(II)

ions to be removed quantitatively from the 0.1 M HCl – x mg Pd(II)/L (where x =

100, 500 or 1000) solution. The sorption capacity was as follows: 10 mg/g, 49.99

mg/g and 99.98 mg/g, respectively. The initial Pd(II) concentration affects the time

required to reach the system equilibrium. The Langmuir maximum sorption

capacity for Purolite is equal to 504.3 mg/g. Purolite S-984 can be regenerated

using different experimental conditions with different efficiency and after the

desorption process the capacity of resin remains high. The separation of noble metal

ions from the tertiary component solutions is difficult and was not achieved by the

applied eluting agents. Purolite S-984 sorbed all noble metal ions from the tertiary

component Pd(II)-Pt(IV)-Au(III) solutions without preference for any of them.

References:

[1] F. Helfferich, Ion Exchange, McGraw Hill, New York 1962.

[2] C. E. Harland, Ion Exchange: Theory and Practice, Second Ed., The Royal

Society of Chemistry, Cambridge 1994.

[3] H. Hubicka, D. Kołodyńska, Hydrometallurgy, 62 (2001) 107.

[4] Z. Hubicki, G. Wójcik, Desalination, 197 (2006) 82.

[5] Z. Hubicki, M. Leszczyńska, Desalination, 175 (2005) 289.

[6] O.N.Kononova, N.G. Goryaeva, O.V.Dychko, Natural Sci., 1 (2009) 166.

[7] I. Matsubara, Y. Takeda, K. Ishida, Fresenius' J. Anal. Chem., 366 (2000) 213.

[8] A.A. Blokhin, N.D. Abovskii, Y.V. Murashkin, Russ. J. App. Chem., 80

(2007) 1058.

[9] A. Da browski, Z. Hubicki, P. Podkościelny, E. Robens, Chemosphere, 56 (2004) 91.

http://rd.springer.com/search?facet-author=%22A.+A.+Blokhin%22http://rd.springer.com/search?facet-author=%22N.+D.+Abovskii%22http://rd.springer.com/search?facet-author=%22Yu.+V.+Murashkin%22http://www.sciencedirect.com/science?_ob=RedirectURL&_method=outwardLink&_partnerName=27983&_origin=article&_zone=art_page&_linkType=scopusAuthorDocuments&_targetURL=http%3A%2F%2Fwww.scopus.com%2Fscopus%2Finward%2Fauthor.url%3FpartnerID%3D10%26rel%3D3.0.0%26sortField%3Dcited%26sortOrder%3Dasc%26author%3DDa%25CC%25A7browski,%2520A.%26authorID%3D7101722036%26md5%3D2a6e2ee03b132a460e8310a31ddd47aa&_acct=C000059500&_version=1&_userid=4479552&md5=3f244e28a29c5b3de5c30c69ecbd7ad1http://www.sciencedirect.com/science?_ob=RedirectURL&_method=outwardLink&_partnerName=27983&_origin=article&_zone=art_page&_linkType=scopusAuthorDocuments&_targetURL=http%3A%2F%2Fwww.scopus.com%2Fscopus%2Finward%2Fauthor.url%3FpartnerID%3D10%26rel%3D3.0.0%26sortField%3Dcited%26sortOrder%3Dasc%26author%3DHubicki,%2520Z.%26authorID%3D7003490656%26md5%3Dc062b9a689197d06d7f88196cf0aaac1&_acct=C000059500&_version=1&_userid=4479552&md5=f589433b3c84de28995753b80d683df2http://www.sciencedirect.com/science?_ob=RedirectURL&_method=outwardLink&_partnerName=27983&_origin=article&_zone=art_page&_linkType=scopusAuthorDocuments&_targetURL=http%3A%2F%2Fwww.scopus.com%2Fscopus%2Finward%2Fauthor.url%3FpartnerID%3D10%26rel%3D3.0.0%26sortField%3Dcited%26sortOrder%3Dasc%26author%3DPodko%25C5%259Bcielny,%2520P.%26authorID%3D6603159248%26md5%3D6a67249beb4640a639fa2dc6a96a1b60&_acct=C000059500&_version=1&_userid=4479552&md5=0d5df093e54cada16810b1bd535ddbechttp://www.sciencedirect.com/science?_ob=RedirectURL&_method=outwardLink&_partnerName=27983&_origin=article&_zone=art_page&_linkType=scopusAuthorDocuments&_targetURL=http%3A%2F%2Fwww.scopus.com%2Fscopus%2Finward%2Fauthor.url%3FpartnerID%3D10%26rel%3D3.0.0%26sortField%3Dcited%26sortOrder%3Dasc%26author%3DRobens,%2520E.%26authorID%3D7005748372%26md5%3D94fde200b7f3aaed0c2d18ffe045ee2c&_acct=C000059500&_version=1&_userid=4479552&md5=5d29fd053574565ceaf8c6b290d51043http://www.sciencedirect.com/science/journal/00456535

FLUORESCENCE QUENCHING PROCESS OF PORPHYRIN

SYSTEMS AS A RESULT OF INTERACTIONS WITH

BIOLOGICALLY ACTIVE COMPOUNDS

Magdalena MAKARSKA-BIAŁOKOZ

DEPARTMENT OF INORGANIC CHEMISTRY

The porphyrin systems are characterized as the substances showing high

intensity of absorption and emission and ability to electron transfer, as well as

sensibility for the subtle changes proceeding in the reaction environment.

Spectroscopic properties of this class of compounds, primarily their fluorescence

intensity, are subject to limitation as a result of the change of their structure during

interactions with different aromatic compounds, such as xanthine and its

derivatives.

One of the examples of such compounds is caffeine (1,3,7-trimethylxanthine),

applied as the component of many drugs and medicaments. The association

processes occurring between chosen water-soluble porphyrins (4,4’,4’’,4’’’-

(21H,23H-porphine-5,10,15,20-tetrayl)tetrakis-(benzoic acid) (H2TCPP),

5,10,15,20-tetrakis(4-sulfonato phenyl)-21H,23H-porphine (H2TPPS4), 5,10,15,20-

tetrakis[4-(trimethylammonio) phenyl]-21H,23H-porphine tetra-p-tosylate

(H2TTMePP), 5,10,15,20-tetrakis(1-methyl-4-pyridyl)-21H,23H-porphine tetra-p-

tosylate (H2TMePyP) and the Cu(II) complexes of H2TTMePP and H2TMePyP) and

aromatic compounds (caffeine, nucleic bases, nucleosides and nucleotides) were

monitored before with use of UV-VIS and emission spectroscopy techniques [1, 2].

The spectroscopic data obtained during these studies became the base for the

determining both association (KAC of the order of magnitude of 103-10

5 mol

-1) and

fluorescence quenching constants (KSV of the order of magnitude of 103 mol

-1) in

the systems examined. Taking into consideration the 1:1 model of complex

formation, the calculations of the association constants were done applying the

equation based on Bjerrum function modified by Beck,

][][1

][

1

110 PLK

LKA

where A is the absorbance; 0, the molar absorbance index for starting porphyrin; 1

and K1 are the molar absorbance index and the gradual binding constant,

respectively, when [L] and [P] stand for the analytical concentration of ligand

(caffeine) and porphyrin. Whereas the fluorescence quenching constants were

determined using Stern-Volmer equation,

][10

QKF

FSV

where F0 and F are the fluorescence intensities in the absence and presence of

quencher, respectively; [Q] is the concentration of quencher, KSV is the Stern-

Volmer quenching constant. For all calculations the non-linear curve-fitting

procedure based on Marquardt–Levenberg algorithm from Sigma Plot (version 9.0,

Jandel Corp.) database program, modified for the particular systems, was employed.

639.5-642.5 nm

H2TTMePP 3.27*10-7 mol dm-3 + caffeine

CM porph. * 10-7

2.0 2.2 2.4 2.6 2.8 3.0 3.2

flu

ore

scen

ce (

a.u

.)

6

8

10

12

14

16

18

exc.412 nm

em.642.5nmem.max

em.639.5nm

[nm]

550 600 650 700 750

flu

ore

scen

ce (

a.u

.)

0.00

5.00

10.00

15.00

20.00

Fig. 1 The process of fluorescence quenching during interactions between H2TTMePP and

caffeine: the dependence of fluorescence intensity vs. porphyrin molar concentration (left

plot) and the decrease of fluorescence intensity (emission spectra, right plot).

The obtained results show that caffeine can interact with water-soluble

porphyrins and through formation of stacking complexes is able to quench their

ability to emission. The bathochromic effect and hypochromicity of the Soret

maximum in the absorption spectra of the particular porphyrins, as well as the

fluorescence quenching in emission spectra point at the decrease of luminescence

properties of water-soluble porphyrins examined and can be predominantly

attributed to the process of static quenching. The magnitude of calculated KAC and

KSV constants depends strongly on the spatial structure both the particular porphyrin

and the aromatic compound. The studies described in this report are indispensable

for investigating of the processes related to porphyrin chemistry (especially the

phenomenon of fluorescence quenching), in the development of new classes of

modified porphyrins of special properties or artificial receptors, as well as in

monitoring of the porphyrin-toxic substances interactions or environmental and

sanitary parameters, where there is a great demand for different kinds of chemical

sensors.

References:

[1] M. Makarska-Bialokoz, J. Fluoresc., 22 (2012) 1521.

[2] M. Makarska-Bialokoz, Cent. Eur. J. Chem., 11 (2013) 1360.

ADSORPTION OF PHOSPHATE(V) ON BENTONITE

Agnieszka GŁADYSZ-PŁASKA, Marek MAJDAN DEPARTMENT OF INORGANIC CHEMISTRY

Among the numerous contaminants present in wastewater, phosphorus is

particularly dangerous. After a treatment process, it is still found in sewage sludge.

If the element enters the environment, it may cause eutrophication, which is a

serious threat to the water environment. The environmental effects, however, are

dependent on the chemical form of phosphorus. By using a speciation analysis, it is

possible to determine a selected chemical form of phosphorus and predict its effects

on the environment. Phosphorus is found in the form of phosphates in wastewater,

which includes organic phosphate, inorganic phosphate (orthophosphate) and

polyphosphate (particulate phosphorus). Sources of phosphorus are found in

excessive use of synthetic fertilisers, animal-based fertilisers, detergents, pigments,

water treatment and mineral processing. Phosphorus is also used in consumer

products and industrial processes that involve particles of colloidal nature [1, 2].

Several methods are available for removing phosphate from aqueous solution,

such as chemical precipitation, solvent extraction, and adsorption. Among these,

adsorption is an attractive method due to its high efficiency, ease of handling, and

availability of different adsorbents. Various kinds of new adsorbents for removing

and recovering phosphate have been reported, among which natural clays and their

composites are considered as particularly effective, low-cost, and chemical stability

[3].

The aim of the investigation was to determine the suitability of the bentonite

for removal of phosphate from aqueous solutions. Various parameters, including

initial phosphate(V) concentration, operating temperature, and solution pH, have

been investigated in batch kinetic experiments and desorption studies. All the

experimental results have been analysed by applying adsorption isotherms and

batch kinetic models. The bentonite saturated by hexadecyltrimethylammonium

bromide was used as an organoclay. The initial and the equilibrium concentrations

of phosphate ions in the aqueous phase were determined by spectrophotometric

phosphormolybdic method [4].

The bentonite is an effective sorbent for removing phosphate(V) from aqueous

solution. The kinetics of adsorption follows the pseudo-second-order model,

indicating that the adsorption was controlled by chemisorption process chich was

found to be endothermic and spontaneous. During studying the pH influence on the

adsorption process the amount of phosphate adsorbed onto HDTMA-bentonite at

pH 6.7 was the greatest (Fig. 2).

Fig. 1. The effect of time on the phosphate(V) adsorption at 293 K, pH = 6.1 (cin =0.0005M)

on HDTMA-bentonite.

Fig. 2. The effect of pH on the phosphate(V) adsorption at 293 K, (cin =0.0005M) on

HDTMA-bentonite.

References:

[1] Ch. Hinz, Geoderma 99 (3–4) (2001) 225–243.

[2] W. Jiang, S. Zhang, X. Shan, M. Feng, Y.G. Zhu, R.G. McLaren, Environ.

Pollut. 138 (2005) 278–284.

[3] T.K. Naiya, A.K. Bhattacharya, S. Mandal, J. Hazard. Mater. 163 (2009) 1254-

1264.

[4] Z. Marzenko, M. Balcerzak, Spektrofotometryczne metody w analizie

nieorganicznej, Wydawnictwo Naukowe PWN SA, Warszawa, 1998.

2 3 4 5 6 7 8 910

15

20

25

30

35

40

45

pHeq

adso

rpti

on P

( %

)

t (h)0 2 4 6 8 10

ad

sorp

tio

n P

(%

)

20

40

60

80

100

LUMINESCENCE SPECTRA OF URANIUM ON CLAY

Agnieszka GŁADYSZ-PŁASKA, Marek MAJDAN DEPARTMENT OF INORGANIC CHEMISTRY

The time-resolved laser-induced fluorescence spectroscopy (TRLFS), applied

as the method to study the kind of U(VI) surface complexes on clays, provides the

information about both lifetime and spectral characteristics of the adsorbed species,

which allows to point out the number of different species and their spectral identity.

The TRLFS technique can supply new insight into the actinide surface

complexation and, therefore, it can contribute to developed knowledge of actinide

behaviour in the environment. Figure 1 shows the typical fluorescence emission

spectrum of the free uranyl ion ([U(VI)] = 5·10-6

mol/dm3) at pH = 6.5 and

adsorbed on the clay (Fig. 1). The lifetimes of U(VI) fluorescence species were

determined from the bi-exponential fit analysis of the obtained data indicating at

least two surface species. As follows from this analysis, one point on the decay

curve represents the value of fluorescence intensity integrated for all wavelengths at

a given delay time. The fluorescence lifetimes of two U(VI) surface species were

calculated from Eq. (1):

y=y0 + A1e-(x-x0)/t1

+ A2e-(x-x0)/t2

(1)

The TRLFS measurements of uranium(VI) species yield two kinds of information:

the position of the fluorescence emission bands and the fluorescence lifetime. The

fluorescence lifetime varies depending on the number of neighbouring water

molecules surrounding the uranium(VI) atom. The TRLFS spectra of the sorbed

U(VI) surface species on sepiolite at pH 6.5 indicate at least two surface species

with two different fluorescence lifetimes, i.e., one short- and one long- lived

species. The calculated average fluorescence lifetimes of the short- (τ1) and long-

lived (τ2) species are summarized in Table 1. The shorter fluorescence lifetimes

indicate more water molecules in the coordination environment of the respective

adsorbed U(VI) surface species because water molecules quench the fluorescence

[1]. On this basis, it can be assumed that U(VI) forms two surface species on clay

(sepiolite, bentonite and red clay) which differ in the amount of water molecules in

their coordination environment.

Comparison of the mean values of the respective fluorescence lifetimes obtained in

the presence and absence of ODTMA (octadecyltrimethylammonium) allows to

conclude that in the presence of ODTMA, the fluorescence lifetimes of both species

are significantly longer. The shorter fluorescence lifetimes of U-sepiolite indicate

more water molecules in the coordination environment of the respective adsorbed

U(VI) surface species. Baumann et al. [1] attributed the surface species with the

shorter fluorescence lifetime to the bidentate mononuclear inner-sphere surface

complex in which U(VI) is bound to two reactive hydroxyl groups at the broken

edge linked to one Al. Arnold et al. [2] ascribed the surface species with the shorter

fluorescence lifetime to an inner-sphere bidentate surface complex, in which U(VI)

binds to the aluminol groups of edge-surfaces of muscovite. Both researchers

interpreted the surface species with the significantly longer fluorescence lifetimes

as an amorphous U(VI) condensate or nanosized clusters of polynuclear uranyl

surface species.

450 500 550 600 650 7000

500000

1000000

1500000

450 500 550 600 6500

500000

1000000

1500000

450 500 550 600 650 7000

500000

1000000

1500000U-ODTMA-sepiolite

U-sepiolite([U(VI)] = 5·10

-6 mol/dm

3)

at pH = 6.5.

Wavelength (nm)

Flu

ores

cenc

e in

tens

ity

(a.u

.)

A) B)

Fig. 1. Fluorescence emission spectrum of U(VI) adsorbed on the sepiolite (A) and an

aqueous solutions ([U(VI)] = 5∙10-6

mol/dm3) at pH 6.5 (B).

Table 1. Comparison of fluorescence lifetimes (τ1 and τ2 ) of uranium species.

System τ1 , ns τ2, ns

U(VI) (acetale) 2200±320 7320±450

U-sepiolite 2420±430 37950±5710

U-ODTMA-sepiolite 3523±160 45400±1830

U-bentonite Volclay 1090±102 67400

U-PO4-bentonite Volclay 1290 70100

U-red clay 1060 26400

U-PO4-red clay 6530 27550

U-gibbsite 322±25 [1] 5180±400 [1]

U-silica gel 138400±52900 [4] 361800±103200 [4]

U-kaolinite 5900±700 [3] 42500±1700 [3]

U-HA-kaolinite (HA-

humic acid)

4400±600 [3] 30900±3600 [3]

References:

[1] N. Baumann, V. Brendler, T. Arnold, G. Geipel, G. Bernhard, J. Colloid. Interf.

Sci. 290 (2005) 318-324.

[2] T. Arnold, T. Zorn, H. Zanker, G. Bernhard, H. Nitsche, J. Contam. Hydrol. 47

(2001) 219–231.

[3] A. Křepelovǎ, Influence of humic acid on the sorption of uranium(VI) and

americium(III), Disseration, University of Technology, Dresden, 2007.

[4] P. Trepte, Sorption von Radionukliden an Tongestein: Spektroskopische

Referenzdaten. Diploma thesis, University of Applied Science, Dresden (2006).

THE APPLICATION OF MICRO- AND MESOPOROUS

ADSORBENTS FOR ENRICHEMNT AND DETERMINATION OF

CHOSEN ELEMNTS BY USING ATOMIC ABSORPTION

SPECTROMETRY METHODS

Ryszard DOBROWOLSKI

DEPARTAMENT OF ANALYTICAL CHEMISTRY

AND INSTRUMENTAL ANALYSIS

The simplicity of the sol-gel method allows to synthesize wide range of hybrid

porous materials based on silica, which are widely exploited in membranes,

adsorption and catalysis. The sol-gel method provide the opportunity of the

incorporation of different organic groups into the materials structure by co-

condensation of tetraethoxysilane (TEOS) with different functionalized silanes. The

functionalization of the surface layer can affect the sorption characteristics of

obtained materials.

The hydrolysis of TEOS followed by its co-condensation with appropriate

organosilicas monomers leads to the formation of functionalized amorphous

polysiloxane xerogels (APX). The sol-gel method give a possibility to design and

keep control over chemical and physical properties of synthesized micro- and

mesoporous materials.

For the first time ordered mesoporous silicas (OMSs) called M41S were

synthesized in 1990. In 1998 hexagonally arranged and highly ordered mesoporous

silicas (OMSs) were produced at the University of California, Santa Barbara. OMSs

are characterized by tuneable pores size, thick pore walls, high specific surface area,

and good textural properties.

The possibility of functionalization and easy one-step synthesis of the OMSs

and APX makes them promising candidates for environmental applications and for

catalytic and adsorption processes. Functionalized silicas have found applications as

adsorbents of many species including biomolecules, pharmaceuticals and heavy

metal ions. However, the amount of information regarding the application of

mesoporous organosilica materials for removal of noble metals is poor.

Platinum is the most relevant noble metal and due to is high cost and limited

world reserves the recovery of its from waste waters and used converters is a very

important issue. The solution of the problem may be functionalized organosilicas

exhibiting substantial adsorption affinity towards noble metal ions.

In this work the amine-functionalized APX and OMS were synthesized,

characterized and compared as sorbents for Pt(II) ions adsorption.

Synthesis of modified SBA-15 and APX materials were carried out using sol-

gel method. In order to synthesize ordered mesoporous organosilicas (OMOs) 2g of

Pluronic 123 was dissolved in 60 mL of 2M HCl and 11 mL of deionized water.

After 8h of stirring at 40°C tetraethoxysilane (TEOS) was added into solution. After

15 minutes the silane coupling agent was added. The mixture was next stirred for

24h at 40°C and aged for 48h at 100°C. The obtained materials were washed by

using deionized water, filtered and dried at 70°C. Removal of template was done by

tree-time extraction with EtOH at 70°C.

In order to synthesize APX the NH4F was dropped the solution of TEOS

which was dissolved in 15 mL of EtOH. After 15 minutes silane coupling agent was

added into mixture. After two days resulting gel was pounded and dried in vacuum.

The initial molar ratios of monomers used for the one-step synthesis were as

follows: a) (TEOS/ATES=19/1), b) (TEOS/ATES=18/2), c) (TEOS/TMPD=19/1),

d) (TEOS/TMPD=18/2) both for OMOs and APX.

The values of specific surface areas obtained for OMOs were in the range

740–840 m2/g, whereas for APX the corresponding values were lower (280–520

m2/g). It was found that in the case of APX the efficiency of amine groups

incorporation into the final material structure is higher (70-80%) than for OMOs.

The adsorption of Pt(II) ions is strongly pH-dependent. In the case of ATES-

functionalized samples, the highest adsorption capacity is obtained for the

equilibrium pH of 2.5 and 3.3 for OMOs and APX, respectively. The maximum

uptake for TMPED- functionalized SBA-15 is achieved at pH around 2.5, and for

TMPED- functionalized APX the plateau is observed in the range of pH 0.8–5.5.

The kinetic of Pt(II) adsorption onto studied APX is generally slower than in the

case of amine-functionalized SBA-15. In Fig. 1 the effect of chlorides on the

adsorption of Pt(II) is presented. In the case of OMOs and APX modified by ATES

the presence of chlorides concentration higher than 0.01 mol/L causes drastic

decrease of the adsorption by about 80–90 %. Only in the case of TMPD-

functionalized APX chlorides do not cause such drastic decrease of adsorption. The

adsorption isotherms of Pt(II) ions are presented in Fig. 2. The high values of

adsorption capacity makes these materials promising candidates for Pt(IV) removal

and preconcentration.

Fig.1. Impact of chlorides on the Pt(IV)

adsorption onto APX and SBA-15

(TEOS/functionalizing monomer=18/2); m

= 0.05 g, V = 50 ml, T = 25ºC.

Fig.2. Adsorption isotherms of Pt(IV) on

functionalized SBA-15 and APX in respect

to thiourea concentration; (TEOS/

functionalizing monomer=18/2); m = 0.05

g, V = 50 ml, T = 25ºC.

SYNTHESIS, CHARACTERIZATION AND APPLICATION OF SBA-

15 MATERIALS FOR ENRICHMENT AND DETERMINATION OF

CHOSEN METALS USING ATOMIC ABSORPTION

SPECTROMETRY METOD

Joanna DOBRZYŃSKA

DEPARTAMENT OF ANALYTICAL CHEMISTRY

AND INSTRUMENTAL ANALYSIS

Since the discovering in 1998 mesoporous SBA-15 materials, due to their

tunable pores size, thick pore walls, high surface area and good textural properties

are in the spotlight of many researchers all over the world. Due to the hydrothermal

and mechanical stability SBA-15 can find the applications for adsorption of

different substances from diluted aqueous solutions. The simplicity of SBA-15

modification, via sol-gel synthesis, allows to create sorbents exhibiting high

adsorption capacities towards chosen inorganic or organic molecules including:

heavy metal ions, biomolecules or pharmaceutics. The previous data concerning

adsorption of Pt(IV) [1] ions onto functionalized SBA-15 led me to study of Pd(II)

ions adsorption onto modified SBA-15 containing sulfur and nitrogen atoms.

Palladium is widely used in catalytic converters and telecommunication

industry; it also is applied for manufacture of watches and special mirrors. The

increasing use of palladium causes that everlasting control of its content in waters,

soils, food and also in human tissues is necessary. In order to determine palladium

in drinking water and plant samples where it occurs in ultra trace amounts,

enrichment stage has to be introduced to the analytical procedure.

The aim of this study was the synthesis, characteristic and application of

amino- and thiol-functionalized mesoporous organosilicas for Pd(II) ions

adsorption.

Synthesis of modified SBA-15 materials was carried out using sol-gel method.

2g of Pluronic 123 was dissolved in 60 mL of 2M HCl and 11 mL of deionized

water. After 8h of stirring at 40°C tetraethoxysilane (TEOS) was added into

solution. After 15 minutes the silane coupling agent was added, (3-mercaptopropyl)

trimethoxysilane (MPTMS), 3-aminopropyltriethoxysilane (ATES) and N-[3-

(trimethoxysilyl)propyl]-ethylenediamine TMPED. The mixture was stirred for 24h

at 40°C and aged for 48h at 100°C. The obtained materials were washed by using

deionized water, filtred and dried at 70°C. Removal of template was done by tree-

time extraction with EtOH at 70°C.

The object of this work was the synthesis, characteristic and application of

amino-functionalized mesoporous organosilicas for Pd(II) ions adsorption.

The initial molar ratios of monomers used for the one-step synthesis were as

follows: a) (TEOS/ATES=19/1), b) (TEOS/ATES=18/2), c) (TEOS/TMPD=19/1),

d) (TEOS/TMPD=18/2), e) (TEOS/MPTMS=19/1), f) (TEOS/MPTMS=18/2), g)

(TEOS/MPTMS=15/5).

The effect of pH on the Pd(II) adsorption onto modified SBA-15 and the

adsorption kinetic were studied. In the case of the thiol-functionalized SBA-15

materials high adsorption capacities were reached for equilibrium pH lower than 6,

whereas for TMPD and ATES functionalized silicas the optimal adsorption pH

range is from 1.2 to 2.2 and from 4 to 6.4, respectively. The obtained material

exhibit high adsorption capacities, which were assigned by setting the runs of Pd(II)

adsorption isotherms. The maximum static adsorption capacities (MSSCs) are 22,

24, 33, 66, 125, 190 and 280 mg/g for samples a, b, c, d, e, f and g, respectively.

The influence of nitrates and chlorides (Fig.1.) on the Pd(II) ions adsorption and

palladium removing from functionalized SBA-15 using thiourea and inorganic acids

were studied (Fig. 2). Due to incomplete Pd species desorption using inorganic

acids and the possibility of full dilution/digestion of sorbent by using HF solution

the slurry sampling GF AAS was proposed and applied as the most promising

technique for Pd determination in environmental samples after enrichment.

The functionalized SBA-15 exhibit high adsorption capacities, reaching 280

mg/g for organosilica synthesized of TEOS/MPTMS in the molar ratio 15/5. In the

case of the thiourea application 80-100% desorption of Pd species from amine-

functionalized silicas was observed. For thiol-functionalized silicas the desorption

reached maximally 80%. The high adsorption capacities and really fast kinetics

makes the materials promising for Pd(II) recycling from converters.

Fig.1. Impact of nitrates and chlorides on

the Pd(II) adsorption onto

(TEOS/MPTMS=18/2); m = 0.05 g, V = 50

ml, pH=1.2, t = 48h, T = 25ºC

Fig.2. Desorption of Pd(II) from

functionalized SBA-15 by using different

concentrations of thiourea; m = 0.005 g, V

= 2ml, t = 24h, T = 25ºC, a(TEOS/ATES=18/2) =

9.5 mg/g, a(TEOS/TMPD=18/2) = 9.8 mg/g

References:

[1] R. Dobrowolski, M. Oszust-Cieniuch, J. Dobrzyńska , M. Barczak, Colloid.

Surface. A., 435 (2013) 63-70.

THE MODIFIED CARBON NANOTUBES IN ANALYTICAL

APPLICATIONS OF PRECONCENTRATION AND DETERMINATION OF SOME ELEMENTS BY ATOMIC

SPECTROMETRY

Agnieszka MRÓZ DEPARTAMENT OF ANALYTICAL CHEMISTRY

AND INSTRUMENTAL ANALYSIS

Palladium has been used in different areas of science and technology including

agents, brazing alloys, petroleum, electrical industries and catalytic chemical

reactions, especially the usage as an effective catalyte for the fuel control of

automobiles. Environmental or industrial pollutions by palladium have so far been

hardly reported as compared with toxic heavy metals such as cadmium, mercury,

and lead. Exposure to certain level of palladium compounds can cause asthma,

allergy and other serious health problems [1]. So, it is of special interest in

environmental analysis and very important for public health to develop new

separation and preconcentration method for detection of palladium in real samples.

Nowadays, carbon nanotubes (CNTs) have attracted much interest that was

directed toward exploiting unique thermal, mechanical, electronic, and chemical

properties since they were first discovered. The extremely large surface area and the

unique tubular structure make CNTs a promising adsorbent material. The modified

carbon nanotubes can be potentially employed both in the industry for recycling of

precious metals from industrial waste, and – in analytical chemistry – as adsorbents

used for enrichment of trace precious metals [2].

The goal of this work was the synthesis and characteristic of modified

multiwalled carbon nanotubes (MWCNTs). Moreover, the performances of

modified multiwalled carbon nanotubes were tested as a new sorbent for the

preconcentration of trace Pd(II). Adsorption of Pd(II) were carried out in a static

system, and Pd(II) were determined by GF AAS technique.

MWCNTs were modified by compounds with different groups:

- 3-aminopropyltriethoxysilane (APTES)

- ethylenediamine (EDA)

- 3-mercaptopropyltrimethoxysilane (MPTMS)

- 2-cyanoethyltriethoxysilane (CETES)

- 3-thiocyanatopropyltriethoxysilane (TCTES)

- diethylphosphatoethyltriethoxysilane (DPTES)

- 1-(2-pyridylazo)- 2-naphthol (PAN)

Prior to modification, MWCNTs were oxidized with concentrated nitric acid,

in order to open the MWCNT ends and generate carboxyl groups. The treatment

was carried out by dispersing 50 mL of concentrated HNO3 to 1.0 g of MWCNTs,

and then heating for 4 h at 100oC. Afterward, the oxidized MWCNTs were washed

with distilled water until removing any excess of nitric acid (neutral pH of

solution). Then, about 1.5 g of oxidized MWCNTs were dispersed in 80 mL of

toluene and 0.01 mol of the modifying agent were added and kept under reflux at

65°C for 3 h. After cooling to room temperature, the MWCNTs were washed with

toluene and ethanol and dried at 60 °C for 12 h. Modification of nanotubes surfaces

as a result of chemical functionalization was confirmed through the presence of

characteristic groups examined by X-ray photoelectron spectroscopy (XPS).

The basic parameters affecting the adsorption capacity of Pd(II) ions on

modified carbon nanotubes were studied and the effect of MWCNTs modification

has been determined by studying the initial runs of adsorption isotherms (Fig.1).

The value of the Pd(II) adsorption is depended on both the carbon nanotubes

modification and the pH of solution. The maximum Pd(II) adsorption onto modified

MWCNTs occurs in the equilibrium pH ranges of 2.0-4.0. In order to evaluate the

potential of modified MWCNTs for the analytical application, the effect of Cl- and

NO3- was studied under optimized adsorption conditions (Fig. 2). Obtained results

have shown that NO3- ions do not interfere in the adsorption of Pd(II). In turn, in the

case of high concentration of Cl- ions (more than 0.1 mol/L), the decrease of Pt(IV)

adsorption onto modified CNTs is observed.

The modified MWCNTs exhibit satisfying adsorption kinetics and high

adsorption capacities. The maximum adsorption capacity was found to be as high as

55 mg/g, what together with favorable adsorption kinetics makes these materials

promising candidates for Pd(II) removal and preconcentration.

Fig. 1. Initial runs of adsorption

isotherms of Pd(II) onto modified

MWCNTs; m=0.01 g, V=5 mL, pH=2.5,

t=24 h, T=25ºC.

Fig. 2. The influence of NO3

- on the

Pd(II) adsorption onto modified

MWCNTs; m=0.01 g, V=5 mL,

C=80 mg/L, pH=2.5, t=24 h, T=25ºC.

References:

[1] C. Yuan, Y. Zhang, S. Wang, A. Chang, Microchimica Acta, 173 (2011) 361.

[2] X. Ren, C. Chen, M. Nagatsu, X. Wang, Chemical Engineering Journal, 170

(2011) 395.

ELIMINATION OF INTERFERENCES IN VOLTAMMETRIC

STRIPPING DETERMINATION OF LEAD USING AMBERLITE

XAD RESIN

Mieczysław KOROLCZUK, Małgorzata GRABARCZYK, Iwona RUTYNA

DEPARTMENT OF ANALYTICAL CHEMISTRY

AND INSTRUMENTAL ANALYSIS

Lead is one of the most toxic heavy metals with major interest in

environmental safety. Even small amounts of lead that enter the environment should

be controlled as they result in a cumulative effect. Electrochemical stripping

analysis is generally recognized as one of the most suitable methods for trace metal

determination. The analytical advantages of the stripping voltammetric techniques

include excellent sensitivity with a large useful linear concentration, rapid analysis

times and low cost. These methods have also a weakness - the measurement can be

disturbed by the organic compounds, particularly surface active substances, which

can foul and passive the electrode causing a decrease or total decay of the

analytical signal. It is a special disadvantage during the analysis of environmental

water samples which generally contain organic compounds in different

concentrations.

In the proposed procedure of lead determination an anodic stripping

voltammetry method is exploited and interferences from dissolved organic matter

are drastically reduced by adding to voltammetric cell Amberlite XAD. In such

measurements lead is accumulated on the electrode by its reduction to the metallic

form and, as was proved, it doesn`t adsorb on the resin. While the negative

influence of organic matter is eliminated by adsorption of these substances onto the

surface of Amberlite XAD-7 resin. The purpose of the work was the selection of the

optimal conditions for ultra trace determination of lead in the environmental water

samples containing high concentrations of surface active substances.

The course of the procedures

In order to eliminate interferences caused by surfactants the addition of

Amberlite XAD-7 resin to the voltammetric cell with the analysed sample was

studied. At first the stability of the Pb(II) signal value in the presence of resin was

examined. The experiments were performed for the samples containing 5 × 10-8

mol

L-1

Pb(II) and 0.5, 1 or 1.5 g XAD-7 resin added to 10 mL of the solution. For each

sample the signal of Pb(II) after accumulation on a mercury drop for 30 s at -0.55 V

was recorded and compared with the signal of Pb(II) obtained in the absence of

XAD-7 resin. It was found that in each case the addition of resin to the samples did

not affect the Pb(II) analytical signal value, which confirms that lead does not

adsorb on the surface of the resin. For further measurements the amount of resin

equal to 0.5 g was chosen and it was tested that in the presence of such an amount

of resin the signal of lead was stable for at least 15 min. In standard measurements

the time of mixing the sample with resin for 5 min. was used because, as was

proved in previous papers, further lengthening of the sample contact time with resin

did not maximise the efficiency of organic substance removal.

Voltammetric measurements were made using anodic stripping voltammetry

(ASV) according to the following procedure: A mercury drop was formed and the

preconcentration of lead was carried out for 30 s at -0.55 V whilst stirring the

solution with a magnetic stirring bar. At the end of the preconcentration time, the

stirrer was switched off, and after a 5 s equilibration time, a differential pulse

stripping voltammogram was recorded, while the potential was scanned from -0.55

V to -0.2 V at a scan rate 20 mV s-1

and a pulse height 50 mV.

Analytical parameters

The dependence of the Pb(II) peak current on its concentration was found to be

linear in the range from 2 × 10-9

to 2 × 10-6

mol L-1

for an accumulation time 30 s

and obeyed the equation y = 598x – 1 (y and x are the peak current (nA) and Pb(II)

concentration (µmol L-1

), respectively), with a correlation coefficient of r = 0.998.

The relative standard deviation for 10 replicate measurements of 1 × 10-8

mol L-1

Pb(II) was equal to 3.4 %. The detection limit estimated from three times the

standard deviation for a low Pb(II) concentration and accumulation time of 30 s was

equal to 8.6 × 10-10

mol L-1

.

Achievement

The effect of the chosen surfactants, that is cationic CTAB, anionic SDS and

nonionic Triton X-100, on the lead analytical signal was tested. The obtained results

indicate that the addition of resin drastically eliminates the unwanted negative

influence of the nonionic, anionic and cationic surfactants on lead peak height. In

the presence of Amberlite XAD-7 resin inherency of even 20 mg L-1

of SDS and

CTAB and 15 mg L-1

of Triton X-100 does not affect the lead signal at all. The 20

mg L-1

of Triton X-100 causes a decrease of the lead signal to 80 % of its original

value. It is a very satisfactory result, considering that in the absence of resin even 1

mg L-1

of SDS, CTAB or Triton X-100 causes total decay of lead peak signal.

Other important components of natural organic matter, inevitably present in

natural samples, are humic substances. Out of the total amount of humic substances

in surface waters, fulvic acids typically account for the majority of the dissolved

organic carbon (80 %), with humic acids accounting for the remaining 20 %. In the

presented communication the effect of fulvic acids (FA) and humic aicds (HA) as

representative humic substances was investigated and it was found that when using

the proposed procedure with the addition of Amberlite XAD-7 resin, 20 mg L-1

of

FA and 5 mg L-1

of HA do not disturb the Pb(II) analytical signal, whereas 10 mg L-

1 of HA decreases it to 40 % of the initial value. The typical range of dissolved

organic carbon in natural waters is from 2 - 10 mg L-1

.

RESEARCHES ON ION SELECTIVE ELECTRODE FOR

INDOMETHACIN DETERMINATION

Joanna LENIK DEPARTMENT OF ANALYTICAL CHEMISTRY

AND INSTRUMENTAL ANALYSIS

One of medicines belonging to NSAID-s group is indomethacin (1-(p-

chlorobenzoyl)-5-methoxy -2-methyl-3-indolylacetic acid) (Fig 1). It is commonly

used to reduce fever, pain, stiffness, and swelling. It works by inhibiting the

production of prostaglandins. Indomethacin is a potent drug with many serious side

effects and should not be considered an analgesic for minor aches and pains or

fever. The drug is best used as an anti-inflammatory, rather than an analgesic.

Indomethacin membrane sensors based on different plasticizers and quaternary

ammonium salt tetraoctylammonium 1-(p-chlorobenzoyl)5-methoxy-2-methyl-3-

indolylacetate (INDO–TOA) were prepared.

The electrode’s basic parameters, such as the slope of characteristics, selectivity

(Table 2), response time lifetime, the influence of pH on the electrode’s potential,

were established (Table 1).

The calibration curves were determined in the main ion and interfering ions solution

at pH 8.8 in the range of concentration 10-2

– 10-6

mol L-1

.

The electrode (with PVC membrane plasticized with dibutylphthalate) response to

indomethacin has the sensitivity near Nernstian (-59.8±1.5 mV decade-1

) over the

linear range of 1x10-5

- 1x10-2

mol L-1

and limit of detection 3.16x10-6

mol L-1

. The

present electrodes show clear discrimination of indomethacin ions from several

inorganic, organic and some common drug excipients. This electrode has a response

time 12 s and can be used in the pH range 6.0 - 10.0. The notably property and

attractive quality of the indomethacin sensor is low cost, comfortable application.

The best values of selectivity coefficient in respect of inorganic ions NO3-

> Br-

>Cl- > H2PO4

2-, organic ions: acetate > propionate > formate > citrate > tartrate >

oxalate and amino acids: glutamic acid > glicine > aspartic acid were obtained for

the DBP electrode.

The influence of 1.0x10-5

to 1.0x10-2

mol L-1

of (2-hydroxypropyl)--cyclodextrin on the calibration curve, response time and selectivity of the electrode was

investigated. The concentration of HPCD higher than 1.0x10-2 mol L-1 causes the contraction of the range of linearity (to 1.0x10

-3 – 1.0x10

-2 mol L

-1), an increase of

detection limit (3.16x10-4

mol L-1

) and increase of potential. The response time to a

sudden concentration change of the main ion in the presence of HPCD is not changed.

Table 1. Analytical parameters of Table 2. Selectivity coefficients

indomethacin electrode

Fig. 1. Structure of (1-(p-chlorobenzoyl)-5-methoxy -2-methyl-3-indolylacetic acid) INDO

The analytical usefulness of indomethacin electrode was examined by determining

indomethacin inpharmaceutical preparations containing (1-(p-chlorobenzoyl)-5-

methoxy-2-methyl-3-indolylacetic acid in “Metindol Retard” – ICN Polfa Rzeszów

SA, Poland. The determination was performed by the calibration curve method and

the method of standard addition. Statistical parameters prove to be typical of

analytical methods using ion-selective electrodes: the accuracy (0.8 -2.5 % and the

precision (RSD 0.8 - 5.5 % ).The proposed technique for indomethacin

determination using ion-selective electrode is characterized by good sensitivity,

selectivity, precision, and accuracy and may be successfully applied for fast and

simply determination of indomethacin in pharmaceuticals.

Selectivity coefficients K

Cl-

Br-

NO3-

SO42-

H2PO4-

propionate

citrate

formate

acetate

oxalate

tartrate

glutamic acid

aspartic acid

glycine

malonate

D-mannitol

glucose

lactose

1,17x10-3

8,88x10-3

5,13x10-2

6,64x10-5

1,14x10-4

1,87x10-3

1,78x10-4

1,21x10-3

2,08x10-3

9,38x10-5

1,15x10-4

6,33x10-4

5,6x 10-4

5,19x10-4

3.47x10-3

9.12x10-4

6,16x10-4

6,20x10-4

Parameter Electrode (DPB)

Characteristic slope S

[mV decade-1

]

-59.8 ±

1.5

Linearity range,

[mol L-1

]

Correlation coefficient (r)

Intercept E0 [mV]

10-5

÷ 10-2

0.9980

10.4

Potential drift mV/day

pH range

Response time [s]

Life time, months

7

6.0 ÷ 10.0

12

2

H3CO

N

C O

Cl

CH2COOH

CH3

ADSORPTION OF SODIUM OCTANESULFONATE AND N-

OCTANE-N-METHYLGLUCAMIDE ON MERCURY ELECTRODE

Jolanta NIESZPOREK, Dorota GUGAŁA-FEKNER, Dorota SIEŃKO

DEPARTMENT OF ANALYTICAL CHEMISTRY AND

INSTRUMENTAL ANALYSIS

For the purpose of this study an anionic surfactant, sodium octanesulfonate

and nonionic surfactant, N-octane-N-methylglucamide were choosen. The chosen

surfactant’s concentrations were lower than their critical micellar point. A 1M

NaClO4 solution was used as the base electrolyte. The systems were characterized

by the measurement of differential capacity, zero charge potential (Ez), and surface

tension at this potential. Fig. 1 presents differential capacity-potential curves of the

double layer Hg / 1M NaClO4.

0 -0.4 -0.8 -1.2 -1.6

E / V

10

20

30

C /

F

. cm

-2

1 M NaClO4 pH 3

1.10-5 M

5.10-5 M

1.10-4 M

3.10-4 M

4.10-4 M

5.10-4 M

6.10-4 M

1.10-3 M

(a)

0 -0.4 -0.8 -1.2 -1.6

E / V

10

20

30

C /

F

. cm

-2

1M NaClO4 pH 3

2.10-6 M

1.10-5 M

2.10-5 M

3.10-5 M

4.10-5 M

5.10-5 M

1.10-4 M

5.10-4 M

(b)

Fig. 1 Differential capacity curves of the double layer Hg/1M NaClO4 pH 3 in the presence

of various concentrations of sodium octanesulfonate (a) and N-octane-N-methylglucamide

(b).

The highest changes of EZ appeared in solutions with addition of N-octane-N-

glucamide concentration higher than 10-4

M. (Table 1).

Table 1. The values of zero charge potential, Ez vs. Ag/AgCl electrode and surface

tension, z at Ez for the system Hg/1M NaClO4 pH 3 in the presence of various

concentrations of sodium octanesulfonate (a) and N-octane-N-methylglucamide (b).

(a) (b)

c [M] -Ez [mV] γz [mN∙m-1

] c [M] -Ez [mV] γz [mN∙m-1

]

0 471.2 425.5 0 471.2 425.5

1∙10-5

470.8 416.2 2∙10-6

471.0 417.9

5·10-5

469.3 413.7 1·10-5

470.3 412.5

1·10-4

468.7 412.0 2·10-5

469.8 411.2

3·10-4

467.2 407.8 4·10-5

468.7 407.0

4·10-4

466.2 407.0 5·10-5

468.1 404.5

5·10-4

465.9 404.5 1·10-4

466.1 394.9

6·10-4

465.3 402.8 3·10-4

459.0 392.7

1·10-3

462.3 394.4 5·10-4

442.0 388.5

Stronger changes of Ez as well as a significant decrese of differential capacity

curves for nonionic surfactant confirmed a stronger adsorption of N-octane-N-

methylglucamide in comparison with the sodium octanesulfonate. Additionally the

Ez value changes show a mechanism in which both surfactants adsorb with their

hydrocarbon chain on the electrode surface.

ELECTROCHEMICAL AND THERMODYNAMIC STUDY OF THE

ELECTROREDUCTION OF Bi(III) IONS IN THE PRESENCE OF CYSTINE IN SOLUTIONS OF DIFFERENT WATER ACTIVITY

Agnieszka NOSAL - WIERCIŃSKA

DEPARTMENT OF ANALYTICAL CHEMISTRY AND INSTRUMENTAL ANALYSIS

Cystine (RSSR) is available as an individual supplement or as part of protein

supplements. This amino acid participates in a variety of physiological functions,

including the synthesis of insulin and blood plasma proteins. Cystine is a

constituent of hair and nail keratin. It may also prevent the toxic effects of metals

and of the particularly harmful free radicals that are produced in the bodies of

cigarette smokers and alcohol abusers [1,2].

Cystine is electrochemically active and in aqueous solutions it reacts with

mercury forming cysteine mercuric thiolate Hg(SR)2 and cysteine mercurous

thiolate Hg2(SR)2 , which are both strongly adsorbed at the electrode [1].

Furthermore, a considerable influence of water on the surface properties of the

Hg/chlorate(VII) phase boundary in the presence of cystine [2] was observed.

Research methodology is mostly based on electrochemical techniques

(voltammetry, Faradaic impedance), which allow for elucidating the mechanism of

Bi(III) ion electroreduction and determining kinetic parameters, as well as for

correlating these parameters with water activity.

It has been found that cystine catalyzes the process of Bi(III) ion

electroreduction in chlorates(VII), thus meeting the requirements of the “cap-pair”

rule [2]. The obtained results show cystine to have catalytic activity in multistep

Bi(III) electroreduction in chlorate(VII) solutions. This catalytic activity clearly

depends on water activity. In solutions with high water activity, the catalytic

activity of cystine is considerably higher than in solutions with low water activity.

In highly concentrated electrolytes (6–8 mol·dm-3

), the catalytic activity of cystine

is small. It has been shown that the process of Bi(III) ion electroreduction in the

presence of cystine is controlled for all the chlorate(VII) concentrations studied (1 –

8 mol·dm-3

) by the reaction kinetics of the formation of active Bi-Hg(SR)2

complexes preceding electron transfer.

References:

[1] M. Heyrovsky, P. Mader, S. Vavřička, V. Veselá, M. Fedurco, J. Electroanal. Chem, 430(1997)103.

[2] A. Nosal – Wiercińska, Electrochim. Acta, 92, (2013)397.

APPLICATION OF LEAD FILM ELECTRODE MODYFIED WITH

POLIMER FILM TO DETERMINATION OF TRACE CONCENTRATIONS OF BIOLOGICALLY ACTIVE COMPOUNDS

BY ADSORPTIVE STRIPPING VOLTAMMETRY

Katarzyna TYSZCZUK-ROTKO

DEPARTMENT OF ANALYTICAL CHEMISTRY

AND INSTRUMENTAL ANALYSIS

Caffeine (3,7-dihydro-1,3,7-trimethyl-1H-purine-2,6-dione) is an alkaloid from

xanthine group that is widely distributed in various kinds of beverages and food,

such as coffee, tea, coca-cola, cola nuts and chocolate. It can also be purchased

in capsules and tablets for the treatment of asthma, nasal congestion, and headache

or to improve athletic endurance and facilitate weight lost [1]. The popularity of

caffeine containing products is connected with her physiological effects, such as

stimulation of the central nervous system, diuresis and gastric secretion [2].

However, it can cause adverse mutation effects when excessively consumed, such

as inhibition of DNA repair and cyclic AMP phosphodiesterase activity.

Furthermore, it can be a cause of cancer, heart diseases and complications

in pregnant women and aging [3]. For these reasons, it is very importent to control

the concentration of caffeine in its different sources.

The main aim of the study was to optimize and develop a sensitive, fast and

accurate adsorptive striping voltammetric method with the use of Nafion covered

lead film electrode (Nafion/PbFE) for the determination of caffeine in

pharmaceutical formulations and food samples.

In the course of caffeine determination at the Nafion/PbFE the potential of the

electrode was changed in the following sequence: 1 V for 30 s and -1.55 V for 120

s. The first step was applied to clean the electrode from the caffeine remaining after

the preceding measurement. During the second step caffeine was accumulated at the

Nafion/PbFE. Then, after 5 s equilibration time, the anodic differential pulse

voltammograms were registered in the range from 0.65 to 1.6 V, with amplitude of

50 mV, modulation time of 4 ms and scan rate 50 mV s-1

.

Under the optimal analytical conditions, the determination of caffeine with

different concentrations was performed. The calibration graphs for the

accumulation time of 120 s were linear from 5 × 10-8

to 5 × 10-6

mol L-1

for the peak

1 and from 5 × 10-7

to 1 × 10-5

mol L-1

for the peak 2, and obeyed the equations y =

93.01 x + 3.45 and y = 25.71 x – 0.29, respectively, where y is the peak current (nA)

and x is a caffeine concentration (µmol L-1

). The correlation coefficients (R2) for

peaks 1 and 2 were 0.9997 and 0.9999, respectively. The detection limits for peaks

1 and 2 estimated from 3 times the standard deviation for the lowest determined

concentration of caffeine were about 1.5 × 10-8

and 2 × 10-7

mol L-1

, respectively.

The advantage of using the Nafion modified lead film electrode consists in lower

detection limit of caffeine with respect to those reported for the bare and Nafion

covered electrodes [4].

The method was successfully applied to the determination of caffeine in tea,

coffee, soft and energy drinks samples as well as pharmaceutical formulation and

average the contents were in close agreement with those quoted by the

manufacturer and with those obtained by the reported spectrophotometric method

[5].

The Nafion covered lead film electrode was also applied to the determination

of acetaminophen (paracetamol) by adsorptive stripping voltammetry. In the course

of paracetamol determination the accumulation step was carried out at -1.45 V for

60 s. The square-wave voltammograms were recorded at a frequency of 200 Hz,

while the potential was scanned from -0.45 to 1.0 V. The amplitude was 50 mV.

The calibration graph for the accumulation time of 60 s was linear from

5 × 10-7

to 1 × 10-2

mol L-1

and obeyed the equation y = 12.56 x + 0.297, where y

and x are the peak current (µA) and paracetamol concentration (mmol L-1

),

respectively. The correlation coefficient (R2) was 0.9997. The relative standard

deviation for a paracetamol concentration of 1 × 10-5

mol L-1

was 3.8 % (n = 5). The

detection limits for the accumulation time of 30 s estimated from 3 times the

standard deviation for the lowest determined concentration of paracetamol was

about 1.9 × 10-7

mol L-1

.

The method was successfully applied to the determination of paracetamol in

pharmaceutical tablets and average the contents were in close agreement with those

quoted by the manufacturer.

References:

[1] O. Cauli and M. Morelli, Behavioural Pharmacology, 16 (2005) 63.

[2] N. Spătaru, B.V. Sarada, D. Tryk and A. Fuijshima, Electroanalysis, 14 (2002)

721.

[3] J.Y. Sun, K.J. Huang, S.Y. Wei, Z.W. Wu and F.P. Ren, Colloids and Surfaces

B: Biointerfaces, 84 (2011) 421.

[4] L. Švorc, International Journal of Electrochemical Science, 8 (2013) 5755.

[5] A. Belay, K. Ture, M. Redi and A. Asfaw, Food Chemistry, 108 (2008) 310.

APPLICATION OF IONIC LIQUID TO THE CONSTRUCTION OF

COPPER ION-SELECTIVE ELECTRODE WITH SOLID CONTACT

Cecylia WARDAK

DEPARTAMENT OF ANALYTICAL CHEMISTRY

AND INSTRUMENTAL ANALYSIS

The new generation of ion-selective electrodes with internal solid contact has

attracted much attention for the past few years. These electrodes will have certain

advantages over conventional ones, such as the small size, lower cost of production,

and ability to operate in high pressure environments where conventional ISEs might

be damaged. Furthermore, this type of electrode allows for low detection limit,

which was attributed to the absence of transmembrane ion fluxes [1].

The aim of this work was developed of solid contact Cu2+

- ISE using chloride

ionic liquid as transducer media. ILs act as very promising solid contact of ISE with

polymeric membrane because they connect two functions in one membrane

component. On the one hand ILs keep constant concentration of chloride ions in the

membrane phase what guarantee the stability of potential of internal Ag/AgCl

reference electrode. On the other hand they lower the membrane resistance and

reduce anion interference, altogether improving the analytical parameters of the

electrode such as detection limit, measuring range, working pH range and

selectivity [2-4]. In this work the membrane containing three ionic liquid: 1-ethyl-3-

methyl imidazolium chloride (EMImCl), 1-butyl-3-methyl imidazolium chloride

(BMImCl), 1-hexyl-3-methyl imidazolium chloride (HMImCl), as well as the

commonly used potassium tetrakis(p-chlorophenyl) borate KTpClB were

investigated. The 2- nitrophenyl octyl ether (NPOE) was used as membrane

plasticizer and N,N,N′,N′-Tetracyclohexyl-2,2′-thiodiacetamide was used as

ionophore.

An internal Ag/AgCl electrode was prepared as follows: a clean silver wire

was anodized electrochemically for 5 min in 4 M HCl using a constant voltage of 5

V from a power source. Then the electrode was rinsed with water, dried with tissue-

paper and covered by the inner membrane phase.

The electrode membrane phase consists of two layers placed in a Teflon

holder. The inner layer contains plasticizer, PVC and lipophilic additive (ionic

liquid or KTpClB) in which the Ag/AgCl electrode is placed. The outer layer

contains the same components and an ionophore. The outer layer is placed on the

inner layer and it is contacted with the tested solution. In order to prepare the inner

layer the membrane components were weighed, mixed thoroughly and the mixture

was deaerated by means of a vacuum oil pump. The Teflon holder was filled with

the mixture so that the silver-silver chloride electrode was immersed in it. Then the

mixture was gelated at 80 ◦C for 30 min. In order to prepare the outer layer the

ionophore was dissolved in a plasticizer and then mixed with other components.

The mixture was deaerated, placed on the inner layer and gelated at 80 ◦C for 10

min. After cooling to room temperature the sensor was mounted in the electrode

body and conditioned for at least 24 hours in 1x10-3

mol L-1 Cu(NO3)2 to saturate

PVC membrane in the primary ions and then for at least 24 hours in the appropriate

conditioning solution before potentiometric measurements. Concentrations of

conditioning solutions were as follows: 1x10-3

mol L-1

, 1x10-5

mol L-1

, 1x10-7

mol

L-1

and 1x10-9

mol L-1

.

In order to evaluate the effect of ionic additive to the membrane, basic

analytical parameters of studied copper electrodes were determined. The best results

were obtained for electrode having membrane doped with 1-ethyl-3-methyl

imidazolium chloride. The electrode shows a Nernstian response for copper ions

over a wide concentration range (1x10-7

-1x10-1

mol L-1

) and the slope of 28.9

mV/decade. The limit of detection is 3.2x10-8

mol L-1

. It has a fast response time of

5-10 s and can be used for more than 4 months without any divergence in potential.

The proposed sensor is not pH sensitive in the range 2.5-6.0 and shows a very good

discriminating ability towards Cu2+

ion in comparison with some alkali, alkaline

earth, transition and heavy metal ions.

The big potential drift and poor reproducibility is a serious problem of solid

contact electrodes. It is connected with the lack of thermodynamically well-defined

electrochemical interface between the membrane and the electronic conductor. So

the stability and reproducibility of the electrode potential in time were studied. The

results obtained show that the addition of ionic liquid to the membrane stabilize the

electrode potential. For the electrode based on EMImCl the determined drift of

potential was -0.1 mV per day and reproducibility of EMF values for three the same

electrodes was very good (SD≤5.8 mV).

References:

[1] J. Sutter, A. Radu, S. Peper, E. Bakker and E. Pretsch, Anal. Chim. Acta.,

523(2004)53.

[2] C. Wardak , Int.. J. Environ. Anal. Chem., 89(2009)735.

[3] C. Wardak, J. Hazar. Mater., 186(2011)1131.

[4] C. Wardak, Electroanalysis, 24(2012)85.

INFLUENCE OF THE FLUOROCARBON SURFACTANT FILM ON

THE POLYTERAFLUOROETHYLENE AND POLYMETHYL

METHACRYLATE SURFACE TENSION

Katarzyna SZYMCZYK and Bronisław JAŃCZUK

DEPARTMENT OF INTERFACIAL PHENOMENA

Surface tensions, especially of solid-vapour and solid-liquid interfaces, are

important thermodynamic parameters to predict the wetting and adhesion properties

of polymer materials including also their biocompatibility [1]. In the literature it is

suggested that liquid should wet the solid if its surface tension value is equal or

lower than that of a solid [2]. It means that decrease of the water surface tension to

that of solid by the addition of the surface active agent to water fulfils the condition

for spontaneous spreading of aqueous solution of such compounds over the solid

surface. On the other hand, such condition is fulfilled if the solid-solution interface

tension is equal to zero when the surface tension of solution and solid is the same

[2]. However, as follows from the literature in the case of aqueous solutions of

surfactants, the so-called critical surface tension of solid wetting [2] is somewhat

higher or considerably lower than the solid surface tension and in many cases it

depends on the kind of surfactant added to water [3,4]. Such behaviour of aqueous

solution of surfactants in the wetting process is caused, on one hand, by the changes

of the solid-solution interface tension, which strongly depends on the orientation of

surfactant molecules in the surface layer at the solid-solution interface different

from that at the solution-air interface. Thus, the changes of the solid-solution

interface tension can occur in a different direction from that of water surface

tension. On the other hand, this process is caused by the changes of the solid surface

tension as a function of surface active agents concentration. In the literature it is

possible to find different opinions about this problem [3,4].

In the earlier studies on the basis of the contact angle of water, formamide and

diiodomethane, it was proved that the surface tension of polymers, PTFE and

PMMA, SV , is changed under the influence of the fluorocarbon surfactants, the Zonyl FSN-100 (FSN100) and Zonyl FSO-100 (FSO100) film, on their surfaces at

different concentrations in the bulk phase and depends on the time of solution

contact with the polymer surface [5]. From this point of view, it was interesting to

determine the influence of these fluorocarbon surfactants in the solvent composed

of water and contestant concentrations of p-(1,1,3,3-tetramethylbutyl)phenoxypoly

(ethyleneglycols), Triton X-100 (TX100) and Triton X-165 (TX165) on the surface

tension components of PTFE and PMMA surface. From the measurements and

calculations it results that at the concentrations of FSN100 and FSO100 in the range

corresponding to their unsaturated monolayer at the water-air interface [46], the

components and parameters of SV practically do not depend on the fluorocarbon surfactant concentration. In this range of concentration, the surface tension of PTFE

covered with the mixed layers is somewhat higher than for "pure" PTFE and there

are only slight differences between its total surface tension and the Lifshitz-van der

Waals component of this tension. However, if the concentrations of FSN100 and

FSO100 are close to the CMC of a given mixture [6], a moderate decrease of the

surface tension of the PTFE/mixed layer is observed. At the surfactant

concentrations close or higher than their CMC, there is a considerable increase of

the total surface tension of PTFE/mixed layer as well as its Lifshitz van der Walls

component and electron-donor parameter [7].

In the case of PMMA, in the range of concentration lower than CMC, the

density of the adsorbed mixed layer is lower than in the case of PTFE because the

surface tension of the PMMA/mixed layer is close to that of the PMMA in the

absence of any surfactant layer. However, for the lowest concentration of the

hydrocarbon surfactants, if the concentration of fluorocarbon surfactant is close to

that corresponding to the saturated layer at the water-air interface, the surface

tension and particularly its Lifshitz van der Waals component decrease, having a

minimum near its CMC. It should be stressed, in contrast to PTFE, that the work of

adhesion to PMMA for water is higher than for any other of the components of the

mixture of surfactants used for the layer formation. The reason is the lower

tendency that the surfactants have to adsorb at the PMMA-solution interface rather

than at the PTFE-solution one. Therefore, the effect of the presence of an adsorbed

layer on the surface becomes evident for PMMA at higher concentration of the

surfactants mixture than for PTFE. On the other hand, PMMA is a monopolar solid

which has a considerable electron-donor parameter, then there are repulsive forces

between the PMMA surface and the surfactants head. The maximal value of the

surface tension of the PMMA/mixed layer is higher than the surface tension of all

the components of the mixture of surfactants and the maximal total surface tension

of the PTFE/mixed layer. It means that water molecules are present in the mixed

layer of the surfactant and they influence the surface tension of the polymer covered

with a surfactant layer [7].

References:

[1] J.M. Rosen, Surfactants and Interfacial Phenomena, Wiley-Interscience, New

York, 2004.

[2] W.A. Zisman, Contact Angle, Wettability and Adhesion, Advances in Chemistry

Series, vol. 43, Amer. Chem. Soc., Washington, DC, 1964.

[3] T.D. Blake, Wetting, In: T.H. Tadros (Ed.), Surfactants, Academic Press,

Orlando, 1984.

[4] Y. Kitazaki and T. Hata, J. Adhes., 4 (1972) 155.

[5] K. Szymczyk and B. Jańczuk, Ind. Eng. Chem. Res., 51 (2012) 14076.

[6] K. Szymczyk, J. Colloid Interface Sci., 363 (2011) 223.

[7] K. Szymczyk, M. L. González-Martín, J. M. Bruque and B. Jańczuk, J. Colloid

Interface Sci., 417 (2014) 180.

ADSORPTION OF FLUOROCARBON SURFACTANTS AT THE

POLYMER-SOLUTION AND SOLUTION-AIR INTERFACES AND

THE POLYMERS WETTABILITY

Katarzyna SZYMCZYK

DEPARTMENT OF INTERFACIAL PHENOMENA

The important ability of surfactants to promote wetting of solids has been

studied extensively and technologically for decades [1]. The wettability of the

surface of solids d