AK

ADVANCEMENT OF ADSORPTION PROCESS ON ACTIVATED CARBON USING MICROWAVE AND HIGH GRAVIMETRIC TECHNOLOGIES

Presented By

Anirban Kundu (SHC 110090)Institute of Biological Science, University of Malaya

SupervisorsDr. Ghufran Redzwan, Institute Of Biological Science, University of MalayaProf. Mohd. Ali Hashim, Department Of Chemical Engg.,University of MalayaProf. Bhaskar Sen Gupta, Heriot-Watt University, UK (External advisor)

AK2

Presentation overview Introduction Problem statement Aim and Objectives Methodology Results and discussion Conclusion Future work

AK3

INTRODUCTION

AK4

• Industrialization, • Economic

growth, • Indiscriminate

use of resource, • No or poor

treatment method

• Heavy metals, • dyes, • Phenols, • Cyanides, • Acids, • Sulphates, • Organic

substances

• Highly toxic• Carcinogeni

c• Bio-

magnifying capacity

• Chemical precipitation,

• Ion-exchange, • Electrochemical

methods, • Membrane

filtration, • Coagulation–

flocculation, • Flotation, • Fenton method, • Photo-chemical

method and • Adsorption

Why adsorption?• Most

versatile,• Economic • Easy to use

technology

AK5

Challenges in implementation of adsorption on activated carbon for wastewater treatment

Challenges during preparation

Reduction of

preparation time

Reduction of preparation

costRaw

material

Challenges during application

Space Time

Reduction in efficiency and increase in the operating cost

AK6

Microwave technology

High gravimetric technology in rotating packed bed

(HIGEE-RPB)

Locally available agricultural

waste

AIMEnhancement of the efficiency and cost-effectiveness of adsorption process on activated carbon using advanced technologies.

AK7

OBJECTIVE

1. Optimisation of process variables in microwave assisted activated carbon production from locally available waste material.

2. Evaluation of the efficacy of the prepared activated carbon for removal of heavy metal and dye.

3. Application of HIGEE technology in rotating packed bed contactor to minimise the contact time for adsorption.

4. Optimisation of the process parameters of rotating packed bed contactor for heavy metal and dye removal, estimation of the adsorption kinetics, adsorption isotherm.

AK8

METHODOLOGY

AK9

Preparation of activated carbon

from low cost agricultural

waste.

Optimization of preparation

conditions for microwave activation.

Characterisation of the

prepared activated carbon

Optimization of the adsorption process in RPB.

Designing and construction of rotating packed

bed reactor.

Adsorption test with the activated

carbon in RPB

AK10

Name asserted to the prepared activated carbon

Microwave power (W)

Time of irradiation (min)

Ratio of Amount of precursor to Amount of 85% H3PO4

MWAC 1 900 20 1:1

MWAC 2 900 20 1:2

MWAC 3 900 20 1:3

Preparation condition

General approach : at varying impregnation ratio

Nitrogen gas flow rate wads 0.2 (l/min)

AK

Investigating parameters

Level 1 Level 2 Level 3 Level 4

Microwave Power (W) 400 600 800 1000

Time (min) 3 10 17 24

Impregnation ratio

(acid:pks)0.5 1 1.5 2

Conc. of acid (H3PO4) (%) 42.5 85

Levels of the control factors used as preparation parameters.

Experiment No

Microwave Power (W)

Time (min)

Impregnation ratio (acid:pks)

Conc. of acid

(H3PO4) (%)

1 400 3 0.5 42.52 400 10 1 42.53 400 17 1.5 854 400 24 2 855 600 3 1 856 600 10 0.5 857 600 17 2 42.58 600 24 1.5 42.59 800 3 1.5 85

10 800 10 2 8511 800 17 0.5 42.512 800 24 1 42.513 1000 3 2 42.514 1000 10 1.5 42.515 1000 17 1 8516 1000 24 0.5 85

Taguchi Optimization Approach (developed by Genichi Taguchi to improve the quality of manufactured goods)

 L16 array for the different combination of experimental conditions 

Advantages of Taguchi method

• Unique set of “orthogonal array” experiments, balanced with respect to all control factors

• Minimum in number. • Minimum use of resources and brings down the production

cost. • Large number of variables can be studied with a small

number of experiments.• Considers the effects of Noise factors which are inconvenient

to control • Make the process insensitive to the variables.

AK12

 L9 array for fine-tuning the experimental conditions 

Investigating

parameters

Level

1

Level

2

Level

3

Microwave

Power (W)700 800 900

Irradiation

Time (min)13 17 21

Impregnation

ratio (acid :

PKS)

1 2 3

Impregnati

on ratio

Microwave

PowerTime

1 700 13

1 800 17

1 900 21

2 700 17

2 800 21

2 900 13

3 700 21

3 800 13

3 900 17

Levels of the control factors used in fine-tuning

experiment.

Signal to noise (S/N) ratio: larger-the-better= -10 log [mean of sum of square of reciprocal of measured data]Or = – 10 Log10 ( 1/n 1/Yi

2 )

AK

Response Surface Methodology (RSM) Optimization Approach

Factor

Name

Units

Type Low Actual

High Actual

Low Coded

High Coded

Mean

A Time min Numeric

5 20 -1 1 12.5

B Power W Numeric

600 1000 -1 1 800

C IR Numeric

0.5 2 -1 1 1.25

D Conc. of acid

% Numeric

20 100 -1 1 60

Summary of experimental design of preparation of activated carbon

Factor 1 Factor 2 Factor 3 Factor 4Run Type A:Time B:Power C:IR D:conc of acid

min W %1 Fact 20 1000 0.5 202 Fact 20 600 2 203 Center 12.5 800 1.25 604 Axial 12.5 800 0.5 605 Axial 12.5 800 2 606 Fact 5 600 0.5 207 Fact 5 600 0.5 1008 Fact 20 600 0.5 1009 Fact 20 1000 2 100

10 Axial 12.5 800 1.25 10011 Axial 5 800 1.25 6012 Fact 20 1000 2 2013 Axial 12.5 1000 1.25 6014 Fact 5 1000 2 2015 Fact 5 1000 0.5 10016 Center 12.5 800 1.25 6017 Fact 5 600 2 2018 Center 12.5 800 1.25 6019 Axial 12.5 600 1.25 6020 Axial 20 800 1.25 6021 Axial 12.5 800 1.25 2022 Center 12.5 800 1.25 6023 Fact 20 600 2 10024 Fact 20 600 0.5 2025 Fact 5 1000 0.5 2026 Fact 5 1000 2 10027 Fact 5 600 2 10028 Fact 20 1000 0.5 100

Advantages of CCD method

• CCD are very efficient, providing much information on experiment variable effects and overall experimental error in a minimum number of required runs.

• CCDs are very flexible. The availability of several varieties of CCDs enables their use under different experimental regions of interest and operability.

AK14

RESULTS AND DISCUSSION

AK15

PREPARATION OF ACTIVATED CARBON

AK16

SampleAdsorbent pH

BET surface

area(m2 g-1)

Total pore volume(cc g-1)

Average Pore

Diameter(Å)

MWAC 1 5.92 872 0.598 27.4MWAC 2 6 1256 1.010 32.4MWAC 3 6 952 0.778 32.7MWAC T 5 1535 1.022 27.8

MWAC CCD 4.9 1011 0.553 21.89

Physico-chemical properties of the prepared activated carbons

AK17

SEM micrographs and FTIR spectra of the raw material (A and C) and prepared activated carbon at optimized condition (B and D) depicting surface characteristics for MWAC T.

SEM micrographs and FTIR spectra of the raw material (A and C) and prepared activated carbon at optimized condition (B and D) depicting surface characteristics for MWAC CCD

AK

Effects of the Control Factors on S/N ratio for the AC Preparation by Taguchi Method

18

The largest S/N performance corresponds to the best performance characteristic.

Optimum operating conditionsIrradiation Time (min)

Power (Watt)

Impreg-nation ratio

Acid con (%)

17 800 2 Undiluted (85 %) H3PO4

After fine-tune17 700 2 N/A

AK19

Effect of Multiple Variables During the Preparation of AC by CCD Optimization Method

Three dimensional graphical representation of the interaction between (A) time and power, (B) time and IR, (C) power-IR, and (D) time and concentration of acid for Zn adsorption

Optimum operating conditionsIrradiation Time (min)

Power (Watt)

Impreg-nation ratio

Acid conc. (%)

11 676 0.68 Undiluted H2SO4

AK20

APPLICATION OF THE ACTIVATED CARBON ANDEVALUATION OF HIGEE TECHNOLOGY IN ROTATING PACKED BED CONTACTOR

AK21

Adsorption of Chromium on MWAC 2Design-Expert® Software

Adsorption19.075

4.495

X1 = A: Initial Conc.X2 = B: pH

Actual FactorC: Temp = 35.00

20.00

30.00

40.00

50.00

60.00

1.00

2.00

3.00

4.00

5.00

3

6.5

10

13.5

17

A

dsor

ptio

n

A: Initial Conc. B: pH

Design-Expert® Software

Adsorption19.075

4.495

X1 = A: Initial Conc.X2 = C: Temp

Actual FactorB: pH = 3.00

20.00

30.00

40.00

50.00

60.00

20.00

27.50

35.00

42.50

50.00

8

11

14

17

20

A

dsor

ptio

n

A: Initial Conc. C: Temp Design-Expert® Software

Adsorption19.075

4.495

X1 = B: pHX2 = C: Temp

Actual FactorA: Intical Conc. = 60.00

1.00

2.00

3.00

4.00

5.00

20.00

27.50

35.00

42.50

50.00

8

11

14

17

20

A

dsor

ptio

n

B: pH C: Temp

Design-Expert® Software

Adsorption19.075

4.495

X1 = A: Initial Conc.X2 = C: Temp

Actual FactorB: pH = 3.00

20.00

30.00

40.00

50.00

60.00

20.00

27.50

35.00

42.50

50.00

8

11

14

17

20

A

dsor

ptio

n

A: Initial Conc. C: Temp

Design-Expert® Software

Adsorption19.075

4.495

X1 = A: Initial Conc.X2 = B: pH

Actual FactorC: Temp = 35.00

20.00

30.00

40.00

50.00

60.00

1.00

2.00

3.00

4.00

5.00

3

6.5

10

13.5

17

A

dsor

ptio

n

A: Initial Conc. B: pH

Design-Expert® Software

Adsorption19.075

4.495

X1 = B: pHX2 = C: Temp

Actual FactorA: Intical Conc. = 60.00

1.00

2.00

3.00

4.00

5.00

20.00

27.50

35.00

42.50

50.00

8

11

14

17

20

A

dsor

ptio

n

B: pH C: Temp

(B)(A)

(C)

A) Combined effect of initial concentration and pH for chromium adsorption; B) combined effect of initial concentration and temperature; and C) combined effect of pH and temperature

Initial concentration(mg L-

1)

pH

Temp

(oC)

Suggested removal (mg gm-

1)

Obtained removal (mg gm-1)

60 3 50 18.25 19.1

AK22

Temperature (K)

k1(min-1)

k2(g mg-1

min-1)R

2

298 0.0044 0.00220.8046 (first

order)0.9931(seco

nd order)

Kinetic Model Parameters

Isotherm Model ParametersLangmuir Isotherm

Freundlich Isotherm Temkin Isotherm Dubinin–

Radushkevichqmax (mg gm-1)

17.57469 Kf (L g-1) 5.199695 A (L g-1) 1.73 qm 15.63

b (L g-1) 0.203943 1/n 0.3047 b (kJ mol-1) 0.645 K x 10-6

(mol2 kJ-2) 2

    n 3.282     E (kJ mol-1) 0.5

R2 0.9593 R2 0.9697 R2 0.8731 R2 0.7507

Pseudo second order kinetics rate limiting step in the adsorption is mainly chemisorption which involves valency forces resulted in due to sharing or exchange of electrons between adsorbent and adsorbate

AK23

• The centrifugal force generated in the rotating packed bed, influenced the removal of the dye with the aid of increasing mass transfer coefficient.

• The adsorption was fast and within 5 hours, almost 93% dye removal was obtained compared to 54% in traditional shake flask experiment.

• Rotating speed of the rotor and liquid feed rate had significant effect on the removal of the dye.

0 50 100 150 200 250 300 3500102030405060708090

100Comparison dye removal in RPB and Shake flask

% Re-moval RPB 50% Re-moval RPB 100% Re-moval SF 50% Re-moval SF 100

Time, minutes

Perc

ent

rem

oval

Removal of Direct Red 23 in RPB

0 20 40 60 80 100 120 1400

20

40

60

80

100

Effect of rotor speed on adsorption of direct red 23. 628 rpm

855 rpm

1140 rpm

Time, minutes

Perc

ent r

emov

al

0 20 40 60 80 100 120 1400

20

40

60

80

100Effect of feed rate on adsorption of direct red

23.10 L/h

20 L/h

30 L/h

40 L/h

Time, minutes

Perc

ent r

emov

al

AK24

Experiments

Initial

concentrati

on (mg/L

)

qe, exp

(mg/g)

Pseudo-first-order kinetic

model

Pseudo-second-order kinetic model

Intra-particle diffusion

qe,

cal

k1 R2 qe, cal k2 R2 kipd R2

Rotating

packed bed

50 10.1210.1

0.012

0.9617

11.590.008

0.9431 0.604 0.9903

100 14.7316.63

0.008

0.9412

24.940.003

0.4866 0.896 0.9435

Shake flask

50 5.475.34

0.010

0.9738

6.320.027

0.9125 0.324 0.9878

100 8.458.97

0.009

0.9728

11.170.011

0.757 0.517 0.9749

Pseudo-first order, Pseudo-second-order and intra-particle diffusion parameter values

AK

Levels of the control factors used.

Chromium Removal in RPB L16 array for the different combination of experimental conditions 

Investigating parameters

Level 1 Level 2 Level 3 Level 4

Rotating speed (rpm)

400 800 1200 1600

Feed rate (L/h) 20 30 40 50Packing density (kg/m3)

153 255 357 510

Initial Solution pH 2 3 4 5

Rotating

speedFeed rate

Packing density

Initial pH

Percent removal of Cr(VI)

NF 1 NF 2 NF 3

400 20 153 2 60.18 59.57 58.1400 30 255 3 64.5 63.46 63.45400 40 357 4 55.3 55.09 55.02400 50 510 5 50.47 59.78 59.65800 20 255 5 63.1 62.43 61.1800 30 153 4 60.93 68.44 62.25800 40 510 3 81.77 84.87 84.43800 50 357 2 85.69 84.23 84.191200 20 357 3 66.1 65.72 65.711200 30 510 2 77.03 75.67 75.431200 40 153 5 92.46 87.79 92.131200 50 255 4 80.92 80.8 82.771600 20 510 4 67.88 68.04 68.851600 30 357 5 87.53 86.9 86.821600 40 255 2 67.48 65.49 63.231600 50 153 3 73.28 72.56 72.78

Taguchi optimisation approach was used.

AK26The largest S/N performance corresponds to the best performance characteristic.

Investigating parameters

Level Value Predicted Experimental

Rotating speed (rpm)

3 1200 S/N ratio

Mean S/N ratio

Mean

Feed rate (L/h)

4 50 39.20

90.34

39.26

91.83

Packing

density (kg/m3)

3 357

Initial Solution pH

1 2

Effect of the Control Factors

Optimum operating conditions

AK27

0 100 200 300 400 500 600 7000

10

20

30

40

50

60

70

80

90

100

Time (min)

% re

mov

al

Removal of chromium with respect to time in RPB

• About 75% was removed within 20 min

• About 90% removal with in 3 h• Based on the R2 value the second

order kinetics (0.9989) can describe the adsorption kinetics hence chemisorption.

Kinetics of Adsorption in RPB

AK28

• This research was conceived with the objective of advancement of adsorption on activated carbon in wastewater treatment.

• Microwave and high gravimetric technologies were used to reduce the time

and energy use of the total process.

• With the aid of microwave technology the production time of activated carbon was considerably short (17 min and 11 min) hence requiring less energy than conventional process.

Conclusion

AK29

• High gravimetric technology in RPB was employed to reduce the equipment size and faster removal of heavy metal and dye from wastewater. In RPB heavy metal and dye from water were removed successfully. Removal was fast and effectively.

• Thus this study describes an effective production method to produce highly surface area activated carbon from less valuable agricultural carbonaceous biomass. Combination of a advanced microwave technology for heating and high gravimetric technology for intensification of the adsorption process, with optimized processing variables has reduced time and energy usage for the removal of heavy metal and dye from wastewater thus making the process more economic, environment friendly and sustainable.

Conclusion (cont..)

AK

FUTURE WORK The scaling up of the microwave system to produce substantial

quantity of the activated carbon must be considered to match up with the requirement of the industry.

Other heavy metals as well as dyes must also be tested for adsorption on to activated carbon in RPB.

A detail experiments on regeneration of the spent activated carbon are also required to be examined to make the system even more sustainable and environment friendly.

Scale up of the RPB system is also to be considered for industrial use.

30

AK31

List of Publications

1. Kundu, A., SenGupta, B., & Hashim, M. A., Redzwan, G. (2015) Taguchi optimization approach for production of activated carbon from phosphoric acid impregnated palm kernel shell by microwave heating. Journal of Cleaner Production, 105, 420-427. (ISI Q1, IF: 3.844)

2. Kundu, A., Hashim, M. A., SenGupta, B., Sahu, J. N., Mubarak, N. M., & Redzwan, G. (2015). Optimization of the process variables in production of activated carbon by microwave heating. RSC Advances, 5, 35899-35908. (ISI Q1, IF: 3.840)

3. Kundu, A., SenGupta, B., Hashim, M. A., Redzwan, G. (2015) Taguchi optimisation approach for chromium removal in a rotating packed bed contractor. Journal of the Taiwan Institute of Chemical Engineers, 57, 91-97. (ISI Q1, IF: 3.000)

4. Kundu, A., Hassan L. S., Redzwan, G., Robinson, D., Hashim, M. A., SenGupta, B. (2015). Application of a rotating packed bed contactor for removal of Direct Red 23 by adsorption. Desalination and Water Treatment (Accepted) (ISI Q3, IF: 1.173)

5. Kundu, A., Redzwan, G., Sahu, J. N., Mukherjee, S., SenGupta, B., & Hashim, M. A. (2014). Hexavalent Chromium Adsorption by a Novel Activated Carbon Prepared by Microwave Activation. BioResources, 9(1), 1498-1518. (ISI Q1 IF: 1.309)

6. Mubarak, N. M., Kundu, A., Sahu, J. N., Abdullah, E. C., & Jayakumar, N. S. (2014). Synthesis of palm oil empty fruit bunch magnetic pyrolytic char impregnating with FeCl3 by microwave heating technique. Biomass and Bioenergy, 61, 265–275. (ISI Q1, IF: 3.394)

AK32

THANK YOU

University of Malaya (Project no. UM.C/HIR/MOHE/ENG/13 And IPPP project no. Pg040-2012b) for providing the funds for the research work.