Research Article Characterization and Properties of

Research ArticleCharacterization and Properties of Activated CarbonPrepared from Tamarind Seeds by KOH Activation forFe(III) Adsorption from Aqueous Solution

Sumrit Mopoung1 Phansiri Moonsri2 Wanwimon Palas2 and Sataporn Khumpai2

1Department of Chemistry Faculty of Science Naresuan University Phitsanulok Thailand2Naresuan University Secondary Demonstration School Naresuan University Phitsanulok Thailand

Correspondence should be addressed to Sumrit Mopoung sumritmnuacth

Received 19 July 2015 Revised 20 October 2015 Accepted 9 November 2015

Academic Editor Jaya N Sahu

Copyright copy 2015 Sumrit Mopoung et al This is an open access article distributed under the Creative Commons AttributionLicense which permits unrestricted use distribution and reproduction in any medium provided the original work is properlycited

This research studies the characterization of activated carbon from tamarind seed with KOH activation The effects of 05 1ndash15 1KOH tamarind seed charcoal ratios and 500ndash700∘C activation temperatures were studied FTIR SEM-EDS XRD and BET wereused to characterize tamarind seed and the activated carbon prepared from them Proximate analysis percent yield iodine numbermethylene blue number and preliminary test of Fe(III) adsorption were also studied Fe(III) adsorption was carried out by 30mLcolumn with 5ndash20 ppm Fe(III) initial concentrations The percent yield of activated carbon prepared from tamarind seed withKOH activation decreased with increasing activation temperature and impregnation ratios which were in the range from 5409 to8203wtThe surface functional groups of activated carbon are OndashH C=O CndashO ndashCO

3

CndashH and SindashHThe XRD result showedhigh crystallinity coming from a potassium compound in the activated carbon The main elements found in the activated carbonby EDS are C O Si and KThe results of iodine andmethylene blue adsorption indicate that the pore size of the activated carbon ismostly in the range of mesopore and macroporeThe average BET pore size and BET surface area of activated carbon are 679764 Aand 27167m2g respectively Finally the tamarind seed based activated carbon produced with 500∘C activation temperature and10 1 KOH tamarind seed charcoal ratio was used for Fe(III) adsorption test It was shown that Fe(III) was adsorbed in alkalineconditions and adsorption increased with increasing Fe(III) initial concentration from 5 to 20 ppm with capacity adsorption of00069ndash0019mgg

1 Introduction

Tamarind (Tamarindus indica L) was planted on a large scalein India Thailand Indonesia Myanmar and the PhilippinesTamarind fruit consists of pulp and hard-coated seeds Theseeds are 30ndash40of fruit with a large quantity as agrobyprod-uct [1] Tamarind seed powder has been used as a biosorbentfor removal of Cr(VI) from simulated industrial wastewater[2] Tamarind seed has also been used as a raw material forgranular activated carbon prepared by microwave inducedchemical activation for the adsorptive treatment of semi-aerobic landfill leachate [3] In addition tamarind seed wasactivated by H

2SO4at 150∘C The activated carbon product

could adsorb Cr(VI) up to 297mgg at pH 1ndash3 [4]

Pollution of natural water resources by iron is one of themost important problems that face and threaten the worldFe contaminants are produced from liquid wastes dischargedfrom a number of industries [5]Water with high iron contentcan be very objectionable in taste odour or appearanceWith severe iron poisoning much of the damage to thegastrointestinal tract and liver may be the result of highlylocalized iron concentration and free radical productionleading to hepatotoxicity through lipid peroxidation and thedestruction of the hepatic mitochondria With this resultthe liver becomes cirrhotic Hepatoma the primary cancerof the liver has become the most common cause of deathamong patients with hemochromatosis [6] Activated carbonhas been proved to be an excellent adsorbent for removing

Hindawi Publishing Corporatione Scientific World JournalVolume 2015 Article ID 415961 9 pageshttpdxdoiorg1011552015415961

2 The Scientific World Journal

organic or inorganic pollutants [7] It could be produced fromagricultural byproducts with low cost and abundance [8]

In this research tamarind seed was used as precursor forthe production of activated carbon using KOH activationThe effects of KOH tamarind seed ratios and activationtemperature were studied The physical and chemical prop-erties were characterized The adsorption of iodine andmethylene blue was also determined Finally the activatedcarbon prepared in this study was used in preliminary testfor Fe(III) adsorption from aqueous solution

2 Materials and Methods

21 Preparation of Material Tamarind seed (sweet Thaitamarind) was obtained from NakhonThai district Phitsan-ulok province Thailand It was washed and oven dried (SL1375 SHEL LAB 1350 FX) at 105∘C for 3 h Proximate analysiswas used to determine the ash content [9] volatilematter [10]fixed carbon [11] and moisture content [12]

22 Preparation of Charcoal Accurately weighed samples ofdried tamarind seed (weighed with analytical balance Sarto-rius Basic) were carbonized in a closed crucible (size 10573and 10270) at 500∘C in furnace (Fisher Scientific IsotempMuffle Furnace) for 1 hThe charcoal product was ground andsieved to 2mm sizeThe percent yield of tamarind seed basedcharcoal is 4014

23 Preparation of Activated Carbon The tamarind seedcharcoal was mixed with KOH (CARLO ERBA Reagent)using KOH to tamarind seed charcoal ratios of 05 1 10 1and 15 1 (wtwt) The mixtures were activated at 500∘C600∘C and 700∘C in furnace Fourier transform infraredspectrometer (Spectrum GX PerkinElmer) in the range of4000ndash400 cmminus1 was used for characterization of functionalgroups on surface of the all samples The samples wereprepared as pellets using KBr (IR grade) [13] An X-raypowder diffractometer with a Cu tube anode (PW 304060XrsquoPert Pro MPD) was used to record the X-ray patternsof samples Scanning electron microscopy (PHILIPS LEO1455 VP) was used to visualize the surface morphology ofthe carbonized and activated products The samples werecoated with gold by a gold sputtering device for a clearvision of the surface morphology Elemental composition ofthese samples was also determined using scanning electronmicroscopy equipped with energy dispersive spectrometer(EDS)TheEDS spectra showing elemental compositionwereobtained by scanning through the surfaces of the samplesThesurface distributions were collected from SEM pictures usingdifferent magnifications Textural characteristics of only acti-vated carbon prepared using the 10 1 KOH charcoal ratiowith 500∘C activation were determined by N

2adsorption

at minus196∘C on Brunauer-Emmett-Teller surface area analyzer(Micromeritics TriStar II) The samples were degassed at250∘C for 12 h under vacuum before the measurementsThe specific surface areas were estimated by the multipointBrunauer-Emmett-Teller (BET) equation The iodine (01 NCARLO ERBA Reagent) and methylene blue (100 ppm AR

0

10

20

30

40

50

60

70

80

90

500600700

Perc

ent y

ield

of a

ctiv

ated

carb

on (w

t)

05 1 10 1KOH charcoal ratios (wtwt)

15 1

Figure 1 Percent yield of tamarind seed based activated carbonas a function of KOH tamarind seed charcoal ratio and activationtemperature

UNILAB) numbers were also determined for all activatedcarbons

24 Fe Adsorption The activated carbon prepared using10 1 KOH to charcoal mixture with activation at 500∘Cwas used for Fe adsorption experiment Accurately weighedsamples of activated carbon were filled into 30mL columnsSolutions of FeCl

3(AR UNILAB) at initial concentrations

of 5 10 and 20 ppm (pH 796 plusmn 033) were passed throughthe column The eluted solutions were collected for Fe(III)concentration determination by AAS Varian SpectrAA 220(Australia) Fe(III) adsorptions were calculated in mg Fegactivated carbonThepHof Fe(III) solution and leachateweremeasured by pH meter (HORIBA F-21 Japan) The pH ofactivated carbon (1 1 weightvolume of activated carbon toH2O) was also measured by method of Bansode et al [14]

3 Results and Discussion

31 Proximate Analysis of Tamarind Seed and Percent Yield ofActivated Carbon The proximate composition of tamarindseed is 114plusmn 007wtmoisture 165plusmn 004wt ash 6764plusmn130wt volatile matter and 2889 plusmn 045wt fixed carbonwhich makes it suitable precursor for obtaining activatedcarbon [15]

Thepercent yield of tamarind seed based activated carbondecreases as activation temperature increases from 500 to700∘C (Figure 1) This could be attributed to the higherreaction rate of carbon and KOH to release more volatilecomponents with concomitant improvement in the texturalcharacteristics [16] and carbon burn-off [17]

32 Adsorption of Iodine Determining the iodine numberis one of the methods to determine the adsorption capacity

The Scientific World Journal 3

0

50

100

150

200

250

300

350

0 02 04 06 08 1 12 14 16

500600700

Iodi

ne ad

sorp

tion

(mg

g)

KOH charcoal ratios (wtwt)

Figure 2 Iodine adsorption of tamarind seed based activatedcarbon as a function of KOH tamarind seed charcoal ratio andactivation temperature

of activated carbons It is a measure of the micropore (0ndash20 A) content of the activated carbon by adsorption of iodinefrom solution The typical range is 500ndash1200mgg whichis equivalent to surface area of carbon between 900 and1100m2g [17]

It can be seen from Figure 2 that iodine adsorption ofactivated carbon prepared with activation at 500∘C slightlyincreases with increasing impregnation ratios It was shownthat micropore content on surface of activated carbon isslightly increased with increasing impregnation ratios Thisis attributed to more extensive reaction between KOH andsurface carbon [18] leading to increased release of CO

2and

CO gases and creating micropores inside of the mesopores[19] The iodine adsorption of activated carbon preparedwith activation temperature of 600∘C and 10 1 impregnationratio is lower than that of activated carbon prepared withimpregnation ratios of 05 1 and 15 1Thismay be attributedto more extensive reaction of KOH and surface carbon at05 1 impregnation ratio [18] and more excessive carbonburn-off at 15 1 impregnation ratio [17] However the iodineadsorption of activated carbon prepared with activationtemperature of 600∘C is higher than that of activated carbonpreparedwith activation temperature of 500∘C for all impreg-nation ratios This is due to more extensive volatile matterdegradation and increased reaction of KOH and surfacecarbon at higher activation temperature [20] The iodineadsorption at the activation temperature of 700∘Cwas highestfor activated carbon prepared using 10 1 impregnation ratioThe iodine adsorption of activated carbon preparedwith 15 1impregnation ratio was higher than that of activated carbonprepared with 05 1 impregnation ratio It was shown thatmore micropores are created at impregnation ratios lt10 1but the content of micropores decreases at impregnationratios ge10 1 due to more excess carbon burn-off collapseof pore walls [18] or expansion of micropores to mesopores[19] Furthermore the reaction between carbon and KOHmay damage the micropores on the carbon surface becausethe concentration of KOH solution is too high [21]

0

20

40

60

80

100

120

0 05 1 15 2

500600700

Met

hyle

ne b

lue a

dsor

ptio

n (m

gg)


Figure 3 Methylene blue adsorption of tamarind seed basedactivated carbon as a function of KOH tamarind seed charcoal ratioand activation temperature

33 Adsorption of Methylene Blue Activated carbon isamphoteric material which can be positively or negativelycharged depending on the solution pH Attraction betweenactivated carbon and anionic or cationic guest materialsis mainly related to the surface characteristics More neg-atively charged surfaces are obtained at higher pH valuesand this favors the uptake of more cationic groups due todecreased electrostatic repulsion between cations and thesurface of activated carbon and vice versa [22] Methyleneblue (C

16H18N3SCl) is a cationic dye with the estimated

dimensions of 143 nm times 061 nm times 04 nm and its adsorptionby activated carbon is very susceptible to solution pHThe adsorption of methylene blue involves the electrostaticinteraction ofmethylene blue cations with negatively chargedcarbon surface functional groups [22]

Figure 3 shows the methylene blue adsorption ontamarind seed based activated carbon It was shown that themethylene blue adsorption capacity of tamarind seed basedactivated carbon is very high This revealed the fact thatthe pore size of activated carbon is mainly in the mesoporeregime and has negative surface charge which correspondsto resorcinol-formaldehyde based activated carbon [19] andcorncob based activated carbon [23] with KOH activationTamarind seed has pores with size mainly in the mesoporerange [3] As a result tamarind seed based activated carbon ismainly mesoporous and has high methylene blue adsorptioncapacity Another effect is the surface charge of activatedcarbon which is negative at high pH [22] The methyleneblue adsorption on tamarind seed based activated carbonactivated at 500∘C is relatively constant for all impregnationratios of KOH tamarind seed This could be explained byrelatively small change in the mesopore portion of initialtamarind seed during activation at 500∘C For activatedcarbon prepared at 600∘C the methylene blue adsorption


(a) (b)

(c)

Figure 4 Scanning electron micrographs (andashc) and elemental composition determined by EDS (Table 1) of tamarind seed based activatedcarbon prepared with 10 1 impregnation ratio and activated at 500∘C

increases with impregnation ratio rising from 05 1 to 10 1and then remains constant At impregnation ratio of 05 1used for the preparation of activated carbon at 600∘C themethylene blue adsorption is lower than that of activatedcarbons prepared at 500∘C and 700∘C It may be attributedto new micropores being created inside of the mesoporesThis is the result of a higher coverage activated carbon surfacewith potassium compounds which will inhibit the physicalsurface [23] Another reason might be the decomposition ofnegatively charged surface groups with more material beingreleased by KOH activation at high temperature especiallyOH group of KOH [16] At increasing impregnation ratiosmore volatile matter is released and more carbon burn-offtakes place [17] leading to more mesopores or macroporesFor carbon activated at 700∘C there is a slight downwardtrend from ratio 05 1 to 10 1 and then methylene blueadsorption remains constant However the methylene blueadsorption is nearly equal for reagent ratios 10 1 and 15 1at all of the activation temperatures This can be explainedby themesopore remaining unchangedwith increasing burn-off [24] Additionally the charcoal starting materials weresoaked in a large amount of KOH and a thin film of KOHshould be coated on their surface and the interior of char-coals should be covered with KOH completely During theactivation in an inert atmosphere surface pyrolysis does notoccur on the surface of chars causing the surface structureto remain [25] Finally the strongly basic concentrated KOHsolution might also destroy the pore structure of carbon [21]

Table 1

Element Wt AtC 2296 3703O 3415 4135Si 0195 0135K 4094 2028

These results are in accordance with the results of BET wherethe average BET pore size of activated carbon is 679764 A

34 SEM-EDS SEM images of tamarind seed based activatedcarbonwith 10 1 impregnation ratio at an activation temper-ature of 500∘C are shown in Figure 4 It can be seen fromthe micrographs that the external surface of the activatedcarbon particles has cracks crevices (Figures 4(a) and 4(c))and some crystals of various sizes in large holes The crystalsin themacropores (Figure 4(b)) aremost likely the potassiumcompounds as is hinted at by the results of the EDSThe EDSshowed (Table 1) high content of potassium in the activatedcarbon This is due to activation in the presence of KOHwhere K

2CO3and other related compounds form during the

pyrolysis process [18] This result is also in good accordancewith the results of BET because there is large amount ofpotassium compounds covering the surface of the activatedcarbon leading to relatively low BET surface area of only27167m2g

The Scientific World Journal 5T

()

(cmminus1)4000 3000 2000 1000 400

(i)(h)(g)(f)

(e)(d)(c)(b)(a)

O

H

C=

C C

=O

COO

H

CndashO

Cndash

O ndash

CO3

ndashOH

Cndash

C C

ndashH

SindashH

120575Cndash

H

Figure 5 FTIR transmission spectra of (a) activated carbonprepared with 05 1 impregnation ratio and activated at 500∘C(b) activated carbon prepared with 10 1 impregnation ratio andactivated at 500∘C (c) activated carbon prepared with 15 1 impreg-nation ratio and activated at 500∘C (d) activated carbon preparedwith 05 1 impregnation ratio and activated at 600∘C (e) activatedcarbon prepared with 10 1 impregnation ratio and activated at600∘C (f) activated carbon prepared with 15 1 impregnation ratioand activated at 600∘C (g) activated carbon prepared with 05 1impregnation ratio and activated at 700∘C (h) activated carbonprepared with 10 1 impregnation ratio and activated at 700∘C and(i) activated carbon prepared with 15 1 impregnation ratio andactivated at 700∘C

Elemental analysis of the residue found the presence ofC O Si and K (Table 1) Furthermore it was found thatcarbon content was only 2296wt This result is attributedto the reaction between KOH and C which is considered themain reaction [23] It is expected that large amount of carbondecomposed by reaction with potassium hydroxide [16]Therefore the activated carbons obtained by KOH activationhave higher potassium and oxygen contents The content ofSi in the activated carbon roughly corresponds to its contentin the original tamarind seed

35 FTIR Spectra Figure 5 shows the FTIR spectra oftamarind seed based activated carbon prepared with KOH totamarind seed charcoal ratios of 05ndash15 and activated at 500ndash700∘C It can be seen that all of spectra are similarThere are abroad band at about 3200 cmminus1 very weak peak at 1600 cmminus1strong peak at 1400 cmminus1 shoulder peak at 1500 cmminus1 veryweak peak at 1150 cmminus1 and weak peaks at 900 cmminus1 and700 cmminus1 The broad band at 3200 cmminus1 associated with ndashOHstretching vibration of hydroxyl functional groups The veryweak peak at 1600 cmminus1 corresponds to C=C stretching ofthe aromatic rings [16] These could form by decompositionof CndashH bonds to form a more stable aromatic C=C bondsat the higher activation temperatures [26] This feature mayalso be due to C=O groups conjugated with aromatic rings[27] This indicates the formation of carbonyl-containing

groups formed during the aromatization of tamarind seed[28] The intensity of this peak gradually decreases withincreasing activation temperatures and impregnation ratiosThe shoulder peaks at about 1500 cmminus1 and 1400 cmminus1 areattributed to carboxyl-carbonate structures [21] The peak at1400 cmminus1 can be attributed to oxygen containing functionalgroups for example C=O and CndashO of carboxylic groups[27] or in-plane vibration of OndashH of carboxylic group [29]The very weak peak at about 1150 cmminus1 corresponds to thestretching vibration of CndashO group in alcohol phenol etheror ester [17] It could also be attributed to carboxylic groups[29] including ndashCO

3group [18] and the phenolic ndashOH

group [21]The peak at 960 cmminus1 is associated with stretchingvibration of CndashC or CndashH groups [30] or C=O group [31]The peak at about 700 cmminus1 may be due to SindashH stretchingvibration [30] or polycyclic and CndashH bending vibration ofbenzene rings [28]These functional groups canhave negativeor positive charge depending on the solution pH [22]

As compared to tamarind seed char which had beenprepared by Munusamy et al [32] it showed the peaks of OndashH group (3334 cmminus1) CndashH group (2879 cmminus1) C=C group(1548 cmminus1) and CndashC group (1165 cmminus1) It was shown thatNaOH activation resulted in increased functional groupsexcept CH group which disappeared after activation

36 XRD Diffractograms The result of XRD diffractograms(Figure 6) revealed that the activated carbons may containpotassium compounds with high crystallinity after activationwith KOH When compared to tamarind seed char [32] itshowed only amorphous carbon (two broad peaks at around2120579=24∘ and 42∘)This finding is similar to the petroleumcokebased activated carbon prepared with K

2CO3activation [33]

and Enteromorpha prolifera based activated carbon preparedwith KOH activation [29] The reaction of KOH and surfacecarbon (Cf) occurring during activation process is as follows[27]

4KOH + Cf 997888rarr K2CO3+ K2O + 2H

2(1)

K2CO3+ 2Cf 997888rarr 2K + 3CO (2)

K2O + C 997888rarr CndashOndashK + K (3)

CndashOndashK +H2O 997888rarr CndashOndashH + KOH (4)

The reaction on surface of carbon could be explained by thefollowing equation [23]

2KOH 997888rarr K2O +H

2O (dehydration) (5)

Cf +H2O 997888rarr H2+ CO (water-gas reaction) (6)

CO +H2O 997888rarr H

2

+ CO2(water-gas shif t reaction)

(7)

K2O + CO

2997888rarr K

2CO3(carbonate formation) (8)

The final product of activation in the presence of KOHduringthe preparation of activated carbon is K

2CO3(8) Kmetal was


(a)

(b)

(c)

(d)

(e)

(f)

600

400

200

400

200

600

400

200

0

600

400

200

400

200

600

400

200

0

10 20 30 40 50 60 70 80 10 20 30 40 50 60 70 80

Gra

phite

-like

mic

rocr

ysta

llite

Gra

phite

-like

mic

rocr

ysta

llite

KOHmiddotH

2O

K 2O

Kg

raph

iteKO

2K 2

OK

K 2CO

3KH

CO3

K 2CO

3middot15

H2O

K 2O

KHCO

3

Gra

phite

latti

ceK 2

CO3

K 2CO

3

KO2

K 2CO

3

K 2O

Kg

raph

iteKO

2

KO2

K 2O

KK

KHCO

3 K 2CO

3middot15

H2OGra

phite

latti

ce

KO2

K 2CO

3

K 2CO

3

Position (∘2120579) Position (∘2120579)

Figure 6 XRD diffractograms of (a) activated carbon prepared with 05 1 impregnation ratio and activated at 500∘C (b) activated carbonprepared with 05 1 impregnation ratio and 600∘C activation temperature (c) activated carbon with 05 1 impregnated ratio and 700∘Cactivation temperature (d) activated carbon with 05 1 impregnated ratio and 600∘C activation temperature (e) activated carbon with 10 1impregnated ratio and 600∘C activation temperature and (f) activated carbonwith 15 1 impregnated ratio and 600∘C activation temperature

produced during the activation process at gt 700∘C as shownin following equation [23]

K2O +H

2997888rarr 2K +H

2O (reduction by hydrogen) (9)

K2O + Cf 997888rarr 2K + CO (reduction by carbon) (10)

Reactions (9) and (10) occurred at temperatures above780∘C which is the boiling point of potassium leading tohigh loss of potassium [23] During KOH activation processa gasification reaction occurred in which KOH was reducedto K metal K

2CO3 which also formed during the activation

was reduced by carbon to K K2O CO and CO

2and porous

carbon surface was also created at the same time Since theboiling point of K is 780∘C then potassium metal remains inthe activated carbon [18]

Figure 6(andashc) shows the effect of activation temperature(500ndash700∘C)with impregnation ratio of 05 1 on crystallinityof the activated carbon The effect of impregnation ratios(05 1ndash15 1) on the crystallinity of activated carbon preparedat activation temperature of 600∘C is shown in Figure 6(dndashf) These show presence of peaks of many potassium com-pounds For example the peaks at 23∘ 27∘ and 395∘ corre-spond to K

2Owhich forms at temperatures above 500∘CThe

intensity of these peaks increases with increasing activationtemperature (Figure 6(andashc)) but their intensity decreaseswith increasing impregnation ratio for materials prepared at600∘C (Figure 5(dndashf)) The peaks at 225∘ 235∘ 28∘ and315∘ belong to peaks corresponding to KOHsdotH

2O These

peaks are very weak at activation temperatures above 500∘CThis shows that C reduced almost all KOH into K

2CO3and

K The peaks corresponding to K metal appear at 29∘ and42∘ These peaks appear for materials prepared at 500∘Cand above Furthermore the intensity of these peaks tendsto increase as the activation temperature and impregnationratios increase The peaks of K

2CO3and K

2CO3sdot15H2O

occur at 305∘ 315∘ and 385∘ and 32∘ 33∘ 395∘ and 465∘respectively The small peaks at 46∘ 49∘ 56∘ and 58∘ canalso be attributed to K

2CO3[34] The intensity of these

peaks increased with increasing impregnation ratios whichis associated with increased reduction of KOH Howeverthe intensity of the peaks of K

2CO3sdot15H2O decreased as

activation temperature increased This indicates that theextent of dehydration was higher with increasing activationtemperature As a result of this the peaks correspondingto K2CO3increase in intensity as the activation tempera-

ture increases The peaks of KO2and ordered Kgraphite

occurred at 26∘ and 31∘ and at 53∘ and 23∘ respectively Thepresence of these species is the result of partial oxidationof potassium graphite intercalate via chemical reductionof CndashOndashC or CndashOndashH surface functional groups [35] Thecontent of KO

2decreases as activation temperature increases

but increases as impregnation ratios increase Furthermorethe peaks of ordered Kgraphite decrease with increasingactivation temperature and decreasing impregnation ratiosThis suggests that after activation activated carbon hadan amorphous structure and the graphite crystallites are


00002000400060008

0010012001400160018

002

0 5 10 15 20 25

Fe(I

II) a

mou

nt ad

sorp

tion

(mg

g)

Fe(III) initial concentrations (ppm)

69 times 10minus3

16 times 10minus2

19 times 10minus2

Figure 7 Fe(III) adsorption on tamarind seed based activatedcarbon as a function of initial Fe(III) concentration

destroyed by K intercalation [27] The peaks at 35∘ 37∘ and28∘ associated with KHCO

3 which formed from interaction

of K2CO3 H2O and CO

2in air during cooling stage [36]

Its content increased with increasing activation temperaturesand impregnation These results are in agreement with theresults of FTIR and EDS which showed presence of ndashOH andndashCO3groups and K respectively The low intensity peaks at

around 235∘ and 44∘ correspond to the graphite lattice whichdemonstrate that the degree of ordered graphitization ofactivated carbon decreases at higher activation temperaturesand impregnation ratios [37] Finally the peaks between 10∘and 20∘ are attributed to the presence of micropores andmicrocrystallinity in the activated carbon [26] which may bedue to graphite-like microcrystalline structure of multilayerstacks [38]

37 Fe(III) Adsorption Fe(III) adsorption capacity of tam-arind seed based activated carbon increased (00069ndash0019mgg) with initial 5ndash10 ppm Fe(III) concentration (Fig-ure 7) This result can be attributed to the higher initialconcentration providing a higher driving force to overcomemass transfer resistance It may also be due to higherinteraction between Fe(III) and activated carbon As theactivated carbon offers a finite number of surface bindingsites Fe(III) adsorption showed a saturation trend at higherinitial Fe(III) concentration [30] In this experiment the pHof Fe(III) solution is 796 plusmn 033 which is higher than thepHZPC (zero point of charge) of tamarind seed based activatedcarbon (600) as reported by Agarwal et al [2] under similarconditions At pH gt 6 the net surface charge of tamarindseed based activated carbon is negative [2]Therefore Fe(III)cations can be adsorbed on the negatively charged surface ofactivated carbon at solution pH above 6 [39]

4 Conclusion

Tamarind seed could be used for charcoal and activatedcarbon preparation The yield of charcoal product fromtamarind seed prepared by carbonization at 500∘C is4014 wt The percent yield of activated carbon preparedfrom tamarind seed with KOH activation ranges from 5409

to 8203wt using impregnation ratios of 05 1ndash15 1 andactivation temperatures of 500ndash700∘CThe surface functionalgroups present on tamarind seed based activated carbon afteractivation with KOH are OndashH C=O CndashO ndashCO

3 CndashH and

SindashHThese functional groups can be negatively or positivelycharged depending on the solution pH The XRD resultsindicate the presence of a range of potassium compoundson the surface of activated carbon such as K K

2CO3

K2CO3sdot15H2O KHCO

3 KO2 and K

2O The main elements

present in the activated carbon are C O Si and K Theresults of iodine and methylene adsorption SEM and BETconfirmed that the pores of the activated carbon aremostly inrange ofmesopores tomacroporesThe average BETpore sizeof activated carbon is 679764 A Fe(III) adsorptions capacityof tamarind seed based activated carbon activated at 500∘Cusing KOH to tamarind seed charcoal ratio of 10 1 is 69times 10minus3ndash19 times 10minus2mgg as determined in experiments withinitial Fe(III) concentrations of 5ndash20 ppm at pH 796 plusmn 033The next step Fe absorption should be further study for findthe maximum condition isotherm and kinetic

Conflict of Interests

The authors declare that there is no conflict of interestsregarding the publication of this paper

Acknowledgments

This research was supported by Science Classrooms inUniversity-Affiliated School Project Ministry of Science andTechnology of Thailand and Faculty of Science NaresuanUniversity and was partially supported by the Department ofChemistry and Naresuan University Secondary Demonstra-tion School Naresuan University

References

[1] T RameshN Rajalakshmi andK S Dhathathreyan ldquoActivatedcarbons derived from tamarind seeds for hydrogen storagerdquoJournal of Energy Storage vol 4 pp 89ndash95 2015

[2] G S Agarwal H K Bhuptawat and S Chaudhari ldquoBiosorptionof aqueous chromium(VI) by Tamarindus indica seedsrdquo Biore-source Technology vol 97 no 7 pp 949ndash956 2006

[3] K Y Foo L K Lee and B H Hameed ldquoPreparation oftamarind fruit seed activated carbon by microwave heatingfor the adsorptive treatment of landfill leachate a laboratorycolumn evaluationrdquo Bioresource Technology vol 133 pp 599ndash605 2013

[4] S Gupta andBV Babu ldquoUtilization ofwaste product (tamarindseeds) for the removal of Cr(VI) from aqueous solutionsequilibrium kinetics and regeneration studiesrdquo Journal ofEnvironmental Management vol 90 no 10 pp 3013ndash30222009

[5] E M Soliman S A Ahmed and A A Fadl ldquoReactivity ofsugar cane bagasse as a natural solid phase extractor for selectiveremoval of Fe(III) and heavy-metal ions from natural watersamplesrdquo Arabian Journal of Chemistry vol 4 no 1 pp 63ndash702011

[6] G N Kousalya M R Gandhi C S Sundaram and SMeenakshi ldquoSynthesis of nano-hydroxyapatite chitinchitosan


hybrid biocomposites for the removal of Fe(III)rdquo CarbohydratePolymers vol 82 no 3 pp 594ndash599 2010

[7] J Kong Q Yue L Huang et al ldquoPreparation characterizationand evaluation of adsorptive properties of leather waste basedactivated carbon via physical and chemical activationrdquo Chemi-cal Engineering Journal vol 221 pp 62ndash71 2013

[8] E Koseoglu and C Akmil-Basar ldquoPreparation structural eval-uation and adsorptive properties of activated carbon fromagricultural waste biomassrdquo Advanced Powder Technology vol26 no 3 pp 811ndash818 2015

[9] American Standards for Testing of Materials ldquoStandard testmethod for total ash content of activate carbonrdquo ASTMD2866-94 American Standards for Testing of Materials 1996

[10] American Standards for Testing of Materials ldquoStandard testmethod for volatile matter content of activate carbonrdquo ASTMD 5832-95 American Standards for Testing of Materials 1996

[11] American Standard of Testing Material ldquoStandard test methodfor fixed carbon in activate carbonrdquoASTMD3172-89 AmericanStandard of Testing Material 1994

[12] American Standard of Testing Material Standard Test Methodfor Moisture in Activate Carbon ASTM D 2867-95 1996

[13] R Yang G Liu X Xu M Li J Zhang and X Hao ldquoSurfacetexture chemistry and adsorption properties of acid blue 9of hemp (Cannabis sativa L) bast-based activated carbonfibers prepared by phosphoric acid activationrdquo Biomass andBioenergy vol 35 no 1 pp 437ndash445 2011

[14] R R Bansode J N Losso W E Marshall R M Rao andR J Portier ldquoPecan shell-based granular activated carbon fortreatment of chemical oxygen demand (COD) in municipalwastewaterrdquo Bioresource Technology vol 94 no 2 pp 129ndash1352004

[15] R R Gil B Ruiz M S Lozano and E Fuente ldquoInfluence ofthe pyrolysis step and the tanning process on KOH-activatedcarbons from biocollagenic wastes Prospects as adsorbent forCO2

capturerdquo Journal of Analytical and Applied Pyrolysis vol110 no 1 pp 194ndash204 2014

[16] Y Chen B Huang M Huang and B Cai ldquoOn the preparationand characterization of activated carbon from mangosteenshellrdquo Journal of the Taiwan Institute of Chemical Engineers vol42 no 5 pp 837ndash842 2011

[17] C Saka ldquoBET TG-DTG FT-IR SEM iodine number analysisand preparation of activated carbon from acorn shell by chem-ical activation with ZnCl

2

rdquo Journal of Analytical and AppliedPyrolysis vol 95 pp 21ndash24 2012

[18] H Deng G Li H Yang J Tang and J Tang ldquoPreparation ofactivated carbons from cotton stalk bymicrowave assisted KOHand K

2

CO3

activationrdquo Chemical Engineering Journal vol 163no 3 pp 373ndash381 2010

[19] T Mitome Y Uchida Y Egashira K Hayashi A Nishiuraand N Nishiyama ldquoAdsorption of indole on KOH-activatedmesoporous carbonrdquo Colloids and Surfaces A Physicochemicaland Engineering Aspects vol 424 pp 89ndash95 2013

[20] M Loredo-Cancino E Soto-Regalado F J Cerino-Cordova RB Garcıa-Reyes AMGarcıa-Leon andM T Garza-GonzalezldquoDetermining optimal conditions to produce activated carbonfrom barley husks using single or dual optimizationrdquo Journal ofEnvironmental Management vol 125 pp 117ndash125 2013

[21] L Yang X-W Chou C Li X-L Long and W-K YuanldquoReduction of [Fe(III)EDTA]minus catalyzed by activated carbonmodified with KOH solutionrdquo Journal of Industrial and Engi-neering Chemistry vol 19 no 3 pp 784ndash790 2013

[22] Y Gokce and Z Aktas ldquoNitric acid modification of activatedcarbon produced from waste tea and adsorption of methyleneblue and phenolrdquo Applied Surface Science vol 313 pp 352ndash3592014

[23] R-L Tseng S-K Tseng F-C Wu C-C Hu and C-C WangldquoEffects of micropore development on the physicochemicalproperties of KOH-activated carbonsrdquo Journal of the ChineseInstitute of Chemical Engineers vol 39 no 1 pp 37ndash47 2008

[24] F-C Wu R-L Tseng and C-C Hu ldquoComparisons of poreproperties and adsorption performance of KOH-activated andsteam-activated carbonsrdquoMicroporous andMesoporous Materi-als vol 80 no 1ndash3 pp 95ndash106 2005

[25] R-L Tseng and S-K Tseng ldquoPore structure and adsorptionperformance of the KOH-activated carbons prepared fromcorncobrdquo Journal of Colloid and Interface Science vol 287 no2 pp 428ndash437 2005

[26] L Muniandy F Adam A R Mohamed and E-P Ng ldquoThesynthesis and characterization of high purity mixed micro-porousmesoporous activated carbon from rice husk usingchemical activation with NaOH and KOHrdquo Microporous andMesoporous Materials vol 197 pp 316ndash323 2014

[27] Y Ji T Li L Zhu XWang andQ Lin ldquoPreparation of activatedcarbons bymicrowave heatingKOHactivationrdquoApplied SurfaceScience vol 254 no 2 pp 506ndash512 2007

[28] A A Ceyhan O Sahin O Baytar and C Saka ldquoSurfaceand porous characterization of activated carbon prepared frompyrolysis of biomass by two-stage procedure at low activationtemperature and itrsquos the adsorption of iodinerdquo Journal ofAnalytical and Applied Pyrolysis vol 104 pp 378ndash383 2013

[29] Y Gao Q Yue B Gao et al ldquoComparisons of porous surfacechemistry and adsorption properties of carbon derived fromEnteromorpha prolifera activated by H

4

P2

O7

and KOHrdquo Chem-ical Engineering Journal vol 232 pp 582ndash590 2013

[30] H Cherifi B Fatiha and H Salah ldquoKinetic studies on theadsorption of methylene blue onto vegetal fiber activatedcarbonsrdquo Applied Surface Science vol 282 pp 52ndash59 2013

[31] M A Kader M R Islam M Parveen H Haniu and K TakaildquoPyrolysis decomposition of tamarind seed for alternative fuelrdquoBioresource Technology vol 149 pp 1ndash7 2013

[32] K Munusamy R S Somani and H C Bajaj ldquoTamarind seedscarbon preparation and methane uptakerdquo BioResources vol 6no 1 pp 537ndash551 2011

[33] C Lu S Xu andC Liu ldquoThe role of K2

CO3

during the chemicalactivation of petroleum coke with KOHrdquo Journal of Analyticaland Applied Pyrolysis vol 87 no 2 pp 282ndash287 2010

[34] X-F Li Y Zuo Y Zhang Y Fu and Q-X Guo ldquoIn situpreparation of K

2

CO3

supported Kraft lignin activated carbonas solid base catalyst for biodiesel productionrdquo Fuel vol 113 pp435ndash442 2013

[35] J A Michel and C M Lukehart ldquoPartially oxidized potassiumintercalate of ultradispersed diamond a cautionary noterdquo Car-bon vol 86 pp 12ndash14 2015

[36] Y-D Chen M-J Huang B Huang and X-R Chen ldquoMeso-porous activated carbon from inherently potassium-rich poke-weed by in situ self-activation and its use for phenol removalrdquoJournal of Analytical and Applied Pyrolysis vol 98 pp 159ndash1652012

[37] K Wang N Zhao S Lei et al ldquoPromising biomass-basedactivated carbons derived from willow catkins for high perfor-mance supercapacitorsrdquo Electrochimica Acta vol 166 pp 1ndash112015


[38] Y Huang E Ma and G Zhao ldquoThermal and structure analysison reaction mechanisms during the preparation of activatedcarbon fibers by KOH activation from liquefied wood-basedfibersrdquo Industrial Crops and Products vol 69 pp 447ndash455 2015

[39] A Ucer A Uyanik S Cay and Y Ozkan ldquoImmobilisation oftannic acid onto activated carbon to improve Fe(III) adsorp-tionrdquo Separation and Purification Technology vol 44 no 1 pp11ndash17 2005

Submit your manuscripts athttpwwwhindawicom

ScientificaHindawi Publishing Corporationhttpwwwhindawicom Volume 2014

CorrosionInternational Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Polymer ScienceInternational Journal of



CeramicsJournal of


CompositesJournal of

NanoparticlesJournal of



International Journal of

Biomaterials


NanoscienceJournal of

TextilesHindawi Publishing Corporation httpwwwhindawicom Volume 2014

Journal of

NanotechnologyHindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Journal of

CrystallographyJournal of


The Scientific World JournalHindawi Publishing Corporation httpwwwhindawicom Volume 2014


CoatingsJournal of

Advances in

Materials Science and EngineeringHindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Smart Materials Research



MetallurgyJournal of


BioMed Research International

MaterialsJournal of


Nano

materials


Journal ofNanomaterials


organic or inorganic pollutants [7] It could be produced fromagricultural byproducts with low cost and abundance [8]

In this research tamarind seed was used as precursor forthe production of activated carbon using KOH activationThe effects of KOH tamarind seed ratios and activationtemperature were studied The physical and chemical prop-erties were characterized The adsorption of iodine andmethylene blue was also determined Finally the activatedcarbon prepared in this study was used in preliminary testfor Fe(III) adsorption from aqueous solution

2 Materials and Methods

21 Preparation of Material Tamarind seed (sweet Thaitamarind) was obtained from NakhonThai district Phitsan-ulok province Thailand It was washed and oven dried (SL1375 SHEL LAB 1350 FX) at 105∘C for 3 h Proximate analysiswas used to determine the ash content [9] volatilematter [10]fixed carbon [11] and moisture content [12]

22 Preparation of Charcoal Accurately weighed samples ofdried tamarind seed (weighed with analytical balance Sarto-rius Basic) were carbonized in a closed crucible (size 10573and 10270) at 500∘C in furnace (Fisher Scientific IsotempMuffle Furnace) for 1 hThe charcoal product was ground andsieved to 2mm sizeThe percent yield of tamarind seed basedcharcoal is 4014

23 Preparation of Activated Carbon The tamarind seedcharcoal was mixed with KOH (CARLO ERBA Reagent)using KOH to tamarind seed charcoal ratios of 05 1 10 1and 15 1 (wtwt) The mixtures were activated at 500∘C600∘C and 700∘C in furnace Fourier transform infraredspectrometer (Spectrum GX PerkinElmer) in the range of4000ndash400 cmminus1 was used for characterization of functionalgroups on surface of the all samples The samples wereprepared as pellets using KBr (IR grade) [13] An X-raypowder diffractometer with a Cu tube anode (PW 304060XrsquoPert Pro MPD) was used to record the X-ray patternsof samples Scanning electron microscopy (PHILIPS LEO1455 VP) was used to visualize the surface morphology ofthe carbonized and activated products The samples werecoated with gold by a gold sputtering device for a clearvision of the surface morphology Elemental composition ofthese samples was also determined using scanning electronmicroscopy equipped with energy dispersive spectrometer(EDS)TheEDS spectra showing elemental compositionwereobtained by scanning through the surfaces of the samplesThesurface distributions were collected from SEM pictures usingdifferent magnifications Textural characteristics of only acti-vated carbon prepared using the 10 1 KOH charcoal ratiowith 500∘C activation were determined by N

2adsorption

at minus196∘C on Brunauer-Emmett-Teller surface area analyzer(Micromeritics TriStar II) The samples were degassed at250∘C for 12 h under vacuum before the measurementsThe specific surface areas were estimated by the multipointBrunauer-Emmett-Teller (BET) equation The iodine (01 NCARLO ERBA Reagent) and methylene blue (100 ppm AR

0

10

20

30

40

50

60

70

80

90

500600700

Perc

ent y

ield

of a

ctiv

ated

carb

on (w

t)

05 1 10 1KOH charcoal ratios (wtwt)

15 1

Figure 1 Percent yield of tamarind seed based activated carbonas a function of KOH tamarind seed charcoal ratio and activationtemperature

UNILAB) numbers were also determined for all activatedcarbons

24 Fe Adsorption The activated carbon prepared using10 1 KOH to charcoal mixture with activation at 500∘Cwas used for Fe adsorption experiment Accurately weighedsamples of activated carbon were filled into 30mL columnsSolutions of FeCl

3(AR UNILAB) at initial concentrations

of 5 10 and 20 ppm (pH 796 plusmn 033) were passed throughthe column The eluted solutions were collected for Fe(III)concentration determination by AAS Varian SpectrAA 220(Australia) Fe(III) adsorptions were calculated in mg Fegactivated carbonThepHof Fe(III) solution and leachateweremeasured by pH meter (HORIBA F-21 Japan) The pH ofactivated carbon (1 1 weightvolume of activated carbon toH2O) was also measured by method of Bansode et al [14]

3 Results and Discussion

31 Proximate Analysis of Tamarind Seed and Percent Yield ofActivated Carbon The proximate composition of tamarindseed is 114plusmn 007wtmoisture 165plusmn 004wt ash 6764plusmn130wt volatile matter and 2889 plusmn 045wt fixed carbonwhich makes it suitable precursor for obtaining activatedcarbon [15]

Thepercent yield of tamarind seed based activated carbondecreases as activation temperature increases from 500 to700∘C (Figure 1) This could be attributed to the higherreaction rate of carbon and KOH to release more volatilecomponents with concomitant improvement in the texturalcharacteristics [16] and carbon burn-off [17]

32 Adsorption of Iodine Determining the iodine numberis one of the methods to determine the adsorption capacity


0

50

100

150

200

250

300

350

0 02 04 06 08 1 12 14 16

500600700

Iodi

ne ad

sorp

tion

(mg

g)





2and


0

20

40

60

80

100

120

0 05 1 15 2

500600700

Met

hyle

ne b

lue a

dsor

ptio

n (m

gg)








(a) (b)

(c)



Table 1







()

(cmminus1)4000 3000 2000 1000 400

(i)(h)(g)(f)

(e)(d)(c)(b)(a)

O

H

C=

C C

=O

COO

H

CndashO

Cndash

O ndash

CO3

ndashOH

Cndash

C C

ndashH

SindashH

120575Cndash

H









2CO3activation [33]



2(1)

K2CO3+ 2Cf 997888rarr 2K + 3CO (2)








2


(7)

K2O + CO

2997888rarr K



2CO3(8) Kmetal was


(a)

(b)

(c)

(d)

(e)

(f)

600

400

200

400

200

600

400

200

0

600

400

200

400

200

600

400

200

0

10 20 30 40 50 60 70 80 10 20 30 40 50 60 70 80

Gra

phite

-like

mic

rocr

ysta

llite

Gra

phite

-like

mic

rocr

ysta

llite

KOHmiddotH

2O

K 2O

Kg

raph

iteKO

2K 2

OK

K 2CO

3KH

CO3

K 2CO

3middot15

H2O

K 2O

KHCO

3

Gra

phite

latti

ceK 2

CO3

K 2CO

3

KO2

K 2CO

3

K 2O

Kg

raph

iteKO

2

KO2

K 2O

KK

KHCO

3 K 2CO

3middot15

H2OGra

phite

latti

ce

KO2

K 2CO

3

K 2CO

3




K2O +H

2997888rarr 2K +H






2and porous





2O These


2CO3and


2CO3and K

2CO3sdot15H2O











00002000400060008

0010012001400160018

002

0 5 10 15 20 25

Fe(I

II) a

mou

nt ad

sorp

tion

(mg

g)


69 times 10minus3

16 times 10minus2

19 times 10minus2




of K2CO3 H2O and CO





4 Conclusion



3 CndashH and


2CO3

K2CO3sdot15H2O KHCO

3 KO2 and K





Acknowledgments


References





















2



2

CO3













4

P2

O7






CO3



2

CO3















CeramicsJournal of







Biomaterials




Journal of


Journal of





CoatingsJournal of

Advances in








MaterialsJournal of


Nano

materials




0

50

100

150

200

250

300

350

0 02 04 06 08 1 12 14 16

500600700

Iodi

ne ad

sorp

tion

(mg

g)





2and


0

20

40

60

80

100

120

0 05 1 15 2

500600700

Met

hyle

ne b

lue a

dsor

ptio

n (m

gg)








(a) (b)

(c)



Table 1







()

(cmminus1)4000 3000 2000 1000 400

(i)(h)(g)(f)

(e)(d)(c)(b)(a)

O

H

C=

C C

=O

COO

H

CndashO

Cndash

O ndash

CO3

ndashOH

Cndash

C C

ndashH

SindashH

120575Cndash

H









2CO3activation [33]



2(1)

K2CO3+ 2Cf 997888rarr 2K + 3CO (2)








2


(7)

K2O + CO

2997888rarr K



2CO3(8) Kmetal was


(a)

(b)

(c)

(d)

(e)

(f)

600

400

200

400

200

600

400

200

0

600

400

200

400

200

600

400

200

0

10 20 30 40 50 60 70 80 10 20 30 40 50 60 70 80

Gra

phite

-like

mic

rocr

ysta

llite

Gra

phite

-like

mic

rocr

ysta

llite

KOHmiddotH

2O

K 2O

Kg

raph

iteKO

2K 2

OK

K 2CO

3KH

CO3

K 2CO

3middot15

H2O

K 2O

KHCO

3

Gra

phite

latti

ceK 2

CO3

K 2CO

3

KO2

K 2CO

3

K 2O

Kg

raph

iteKO

2

KO2

K 2O

KK

KHCO

3 K 2CO

3middot15

H2OGra

phite

latti

ce

KO2

K 2CO

3

K 2CO

3




K2O +H

2997888rarr 2K +H






2and porous





2O These


2CO3and


2CO3and K

2CO3sdot15H2O











00002000400060008

0010012001400160018

002

0 5 10 15 20 25

Fe(I

II) a

mou

nt ad

sorp

tion

(mg

g)


69 times 10minus3

16 times 10minus2

19 times 10minus2




of K2CO3 H2O and CO





4 Conclusion



3 CndashH and


2CO3

K2CO3sdot15H2O KHCO

3 KO2 and K





Acknowledgments


References





















2



2

CO3













4

P2

O7






CO3



2

CO3















CeramicsJournal of







Biomaterials




Journal of


Journal of





CoatingsJournal of

Advances in








MaterialsJournal of


Nano

materials




(a) (b)

(c)



Table 1







()

(cmminus1)4000 3000 2000 1000 400

(i)(h)(g)(f)

(e)(d)(c)(b)(a)

O

H

C=

C C

=O

COO

H

CndashO

Cndash

O ndash

CO3

ndashOH

Cndash

C C

ndashH

SindashH

120575Cndash

H









2CO3activation [33]



2(1)

K2CO3+ 2Cf 997888rarr 2K + 3CO (2)








2


(7)

K2O + CO

2997888rarr K



2CO3(8) Kmetal was


(a)

(b)

(c)

(d)

(e)

(f)

600

400

200

400

200

600

400

200

0

600

400

200

400

200

600

400

200

0

10 20 30 40 50 60 70 80 10 20 30 40 50 60 70 80

Gra

phite

-like

mic

rocr

ysta

llite

Gra

phite

-like

mic

rocr

ysta

llite

KOHmiddotH

2O

K 2O

Kg

raph

iteKO

2K 2

OK

K 2CO

3KH

CO3

K 2CO

3middot15

H2O

K 2O

KHCO

3

Gra

phite

latti

ceK 2

CO3

K 2CO

3

KO2

K 2CO

3

K 2O

Kg

raph

iteKO

2

KO2

K 2O

KK

KHCO

3 K 2CO

3middot15

H2OGra

phite

latti

ce

KO2

K 2CO

3

K 2CO

3




K2O +H

2997888rarr 2K +H






2and porous





2O These


2CO3and


2CO3and K

2CO3sdot15H2O











00002000400060008

0010012001400160018

002

0 5 10 15 20 25

Fe(I

II) a

mou

nt ad

sorp

tion

(mg

g)


69 times 10minus3

16 times 10minus2

19 times 10minus2




of K2CO3 H2O and CO





4 Conclusion



3 CndashH and


2CO3

K2CO3sdot15H2O KHCO

3 KO2 and K





Acknowledgments


References





















2



2

CO3













4

P2

O7






CO3



2

CO3















CeramicsJournal of







Biomaterials




Journal of


Journal of





CoatingsJournal of

Advances in








MaterialsJournal of


Nano

materials




()

(cmminus1)4000 3000 2000 1000 400

(i)(h)(g)(f)

(e)(d)(c)(b)(a)

O

H

C=

C C

=O

COO

H

CndashO

Cndash

O ndash

CO3

ndashOH

Cndash

C C

ndashH

SindashH

120575Cndash

H









2CO3activation [33]



2(1)

K2CO3+ 2Cf 997888rarr 2K + 3CO (2)








2


(7)

K2O + CO

2997888rarr K



2CO3(8) Kmetal was


(a)

(b)

(c)

(d)

(e)

(f)

600

400

200

400

200

600

400

200

0

600

400

200

400

200

600

400

200

0

10 20 30 40 50 60 70 80 10 20 30 40 50 60 70 80

Gra

phite

-like

mic

rocr

ysta

llite

Gra

phite

-like

mic

rocr

ysta

llite

KOHmiddotH

2O

K 2O

Kg

raph

iteKO

2K 2

OK

K 2CO

3KH

CO3

K 2CO

3middot15

H2O

K 2O

KHCO

3

Gra

phite

latti

ceK 2

CO3

K 2CO

3

KO2

K 2CO

3

K 2O

Kg

raph

iteKO

2

KO2

K 2O

KK

KHCO

3 K 2CO

3middot15

H2OGra

phite

latti

ce

KO2

K 2CO

3

K 2CO

3




K2O +H

2997888rarr 2K +H






2and porous





2O These


2CO3and


2CO3and K

2CO3sdot15H2O











00002000400060008

0010012001400160018

002

0 5 10 15 20 25

Fe(I

II) a

mou

nt ad

sorp

tion

(mg

g)


69 times 10minus3

16 times 10minus2

19 times 10minus2




of K2CO3 H2O and CO





4 Conclusion



3 CndashH and


2CO3

K2CO3sdot15H2O KHCO

3 KO2 and K





Acknowledgments


References





















2



2

CO3













4

P2

O7






CO3



2

CO3















CeramicsJournal of







Biomaterials




Journal of


Journal of





CoatingsJournal of

Advances in








MaterialsJournal of


Nano

materials




(a)

(b)

(c)

(d)

(e)

(f)

600

400

200

400

200

600

400

200

0

600

400

200

400

200

600

400

200

0

10 20 30 40 50 60 70 80 10 20 30 40 50 60 70 80

Gra

phite

-like

mic

rocr

ysta

llite

Gra

phite

-like

mic

rocr

ysta

llite

KOHmiddotH

2O

K 2O

Kg

raph

iteKO

2K 2

OK

K 2CO

3KH

CO3

K 2CO

3middot15

H2O

K 2O

KHCO

3

Gra

phite

latti

ceK 2

CO3

K 2CO

3

KO2

K 2CO

3

K 2O

Kg

raph

iteKO

2

KO2

K 2O

KK

KHCO

3 K 2CO

3middot15

H2OGra

phite

latti

ce

KO2

K 2CO

3

K 2CO

3




K2O +H

2997888rarr 2K +H






2and porous





2O These


2CO3and


2CO3and K

2CO3sdot15H2O











00002000400060008

0010012001400160018

002

0 5 10 15 20 25

Fe(I

II) a

mou

nt ad

sorp

tion

(mg

g)


69 times 10minus3

16 times 10minus2

19 times 10minus2




of K2CO3 H2O and CO





4 Conclusion



3 CndashH and


2CO3

K2CO3sdot15H2O KHCO

3 KO2 and K





Acknowledgments


References





















2



2

CO3













4

P2

O7






CO3



2

CO3















CeramicsJournal of







Biomaterials




Journal of


Journal of





CoatingsJournal of

Advances in








MaterialsJournal of


Nano

materials




00002000400060008

0010012001400160018

002

0 5 10 15 20 25

Fe(I

II) a

mou

nt ad

sorp

tion

(mg

g)


69 times 10minus3

16 times 10minus2

19 times 10minus2




of K2CO3 H2O and CO





4 Conclusion



3 CndashH and


2CO3

K2CO3sdot15H2O KHCO

3 KO2 and K





Acknowledgments


References





















2



2

CO3













4

P2

O7






CO3



2

CO3















CeramicsJournal of







Biomaterials




Journal of


Journal of





CoatingsJournal of

Advances in








MaterialsJournal of


Nano

materials

















2



2

CO3













4

P2

O7






CO3



2

CO3















CeramicsJournal of







Biomaterials




Journal of


Journal of





CoatingsJournal of

Advances in








MaterialsJournal of


Nano

materials













CeramicsJournal of







Biomaterials




Journal of


Journal of





CoatingsJournal of

Advances in








MaterialsJournal of


Nano

materials










CeramicsJournal of







Biomaterials




Journal of


Journal of





CoatingsJournal of

Advances in








MaterialsJournal of


Nano

materials



Documents

Research Article Characterization and Properties of