Pistachio Shell Carbon (PSC) – an agricultural adsorbent for the removal of Pb(II) from aqueous solution

Pistachio Shell Carbon (PSC) – an agricultural adsorbent for the removal of Pb(II) from aqueous solution

Author’s Accepted Manuscript Pistachio Shell Carbon (PSC) – an agricultural adsorbent for the removal of Pb(II) from aqueous solution Shaziya H. Siddi...

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Author’s Accepted Manuscript Pistachio Shell Carbon (PSC) – an agricultural adsorbent for the removal of Pb(II) from aqueous solution Shaziya H. Siddiqui, Rais Ahmad www.elsevier.com/locate/gsd

PII: DOI: Reference:

S2352-801X(16)30075-3 http://dx.doi.org/10.1016/j.gsd.2016.12.001 GSD36

To appear in: Groundwater for Sustainable Development Received date: 4 July 2016 Revised date: 26 December 2016 Accepted date: 27 December 2016 Cite this article as: Shaziya H. Siddiqui and Rais Ahmad, Pistachio Shell Carbon (PSC) – an agricultural adsorbent for the removal of Pb(II) from aqueous s o l u t i o n , Groundwater for Sustainable Development, http://dx.doi.org/10.1016/j.gsd.2016.12.001 This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting galley proof before it is published in its final citable form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.

Pistachio Shell Carbon (PSC) – an agricultural adsorbent for the removal of Pb(II) from aqueous solution Shaziya H. Siddiquia,b*, Rais Ahmada,b a

Department of Chemistry, Sam Higginbottom Institute of Agriculture, Technology and

Sciences, Allahabad-211007 b

Environmental Research Laboratory, Department of Applied Chemistry, Aligarh Muslim

University, Aligarh, 202002, India [email protected] [email protected] *Corresponding author. Department of Chemistry, Sam Higginbottom Institute of Agriculture, Technology and Sciences, Allahabad-211007, India

Abstract The Pistachio Shell Carbon (PSC) is used for the removal of Pb (II) from aqueous solution. The effects of concentration, pH, doses dose and temperature have been studied. The morphology of the surface of the adsorbent was characterized by FTIR. The PSC was characterized by FTIR to determine the presence of functional groups. The

highest

maximummaximum adsorption capacity of 24 mgg-17.9 mg g-1 7.9 mg g-1 of Pb (II) was recorded at pH 6. The point of zero charge for PSC was observed at pH 5.0. the total number of acidic and basic sites available on adsorbent was also reported.

The equilibrium was

attained in 180 mintsmins. The adsorption data were applied to various isotherms model such as Langmuir, Freundlich, Temkin and the data was best described by Langmuir isotherm model. Langmuir model, Freundlich model, Temkin model were applied to describe the adsorption process. The data was best fitted by Langmuir Isotherm model. In order to examine the controlling mechanism of adsorption process pseudo -first order, pseudo-second order and intraparticle diffusion kinetic equation were used to test the experimental data. The result indicates that the adsorption data follows pseudo-second order kinetics. The positive value of ∆H0 and ∆S0 for the adsorption of Pb(II) ion indicates endothermic nature and the randomness at solid/liquid solution. The adsorbent could be desorbed 82.9% of Pb(II) ion by 0.1M HCl.

Keyword: Adsorption, Pistachio Shell Carbon (PSC), FTIR, Temkin, desorption

Introduction The toxic pollutants such as heavy metal and organic pollutants in water and wastewater are becoming concern for public health because of its non biodegradability and persistent in nature. The toxicity of these metals the heavy metals such as Pb2+, Cu2+, Ni2+ etc. are enchanced through accumulation in living tissues and bio-magnification in the food chain (Ann et al.2001). The removal of these the pollutants is required to control the water pollution. Lead, one of the poisonous heavy metal which is hazardous to the human health even at low concentration (Behrami et al.2014). It affects the nervous system causing blood and brain disorders (Ebrahimzadeh et al.2015). Contaminated food or water, accidental ingestion of contaminated soil, dust of lead based paints causes lead poisoning (Ryan et al.2014). Long term exposure of lead causes nephropathy and colic-like abdominal pains (Sabaruddin et al.2006). Therefore, extraction and determination of lead ions in food samples has become a subject of interest worldwide. Moreover, Lead is one of the most interesting problematic heavy metals for removal causing environmental risk and reserve depletion. Lead ions widely used in many industrial applications such as storage battery manufacturing, painting pigment, fuels, photographic materials, explosive manufacturing, automobile, aeronautical and steel industries (Ahmad et al.2013).The permissible limit of Pb(II) ion in wastewater set by EPA is 0.05mgL-1 0.05 mg L-1 and 0.1 mgL-1 by Bureau of Indian standard(BIS) limits for drinking water set by EU, USEPA and WHO are 0.010,0.015 and 0.010 mgL-1 respectively 0.010, 0.015 and 0.010 mg L-1 respectively (Balaria et al. 2008, Bhattacharjee et al. 2003). Therefore, it is necessary to remove Pb (II) from wastewater before disposal. The traditional methods for the treatment of heavy metals such as lead in wastewater are complexation, chemical precipitation, solvent extraction, reverse osmosis, ion exchange, filtration, membrane processes, evaporation and coagulation (Mallampati et al. 2015). But these techniques have disadvantages such as incomplete metal removal, high consumption of reagent and energy, low selectivity, high capital and operation cost and generation of secondary waste that are difficult to dispose off (Eren et al.2009). On other

hand , Adsorption is an effective, economical and environment friendly technique for the removal of pollutant from the wastewater. various low cost adsorbents such as pinus bark powder, treated ginger carbon, polyaniline/iron oxide composite and alumina reinforced polystyrene, Black cumin seeds, Menthe piperita carbon, menthe piperita, Luffa Actangula for the removal of metals/dyes from the aqueous solution have been utilized before in our studies (Ahmad 2009; Ahmad and Kumar. 2010; Ahmad and Kumar 2011; Ahmad and Haseeb 2015; Ahmad and Haseeb 2013; Ahmad and Haseeb 2015). Recently, various agricultural waste materials such as hazelnut straws, peanut shell, banana peel, orange peel, walnut shell, rice husk and saw-dust (Nguyen et al.,2013; Alothman et al.,2013; Ma et al.,2014; Park et al.,2008; Krishnani et al.,2008; Abdolali et al.,2014 a) and forestry materials such as fern leaves (Prasad and Freitas, 2000) have been investigated for the ability to remove different contaminants from the wastewater. Therefore, the performance of waste material in abundance find a low cost and efficient alternative adsorbent is necessary. Pistachio (Pistachia vera L.Anacardiaceace) shell carbon (PSC) an agricultural waste material easily available in India has been used for the removal of Pb(II) ion from the aqueous solution. The effects of various parameters like pH, time, dosage and concentration have been observed. Kinetics, Isotherms and thermodynamic parameters were also evaluated to study the adsorption behavior of Pb(II) ion.

Experimental Chemical and Equipment The Stock solution of Pb (II) (1000 mgL−1) concentration was prepared by dissolving appropriate amount of Pb (NO3)2 (CDH, India). Working reference solutions were obtained by stepwise dilution from stock solution. All reagents were of analytical grade. Atomic absorption spectrophotometer (model GBC Australia) was used for measuring Pb (II) in air– acetylene flame.

Preparation of Pistachio Carbon Pistachia Vera L. was prepared from green pistachio shell wastes procured from a local market (Aligarh) India. Prior to use, the pistachio green shell waste was washed with double distilled water to remove the adhering dirt and then dried at 80 0C OC. The dried materials were then placed in the muffle furnace for 1 hr maintained at 750 0C OC. The resultant carbon obtained was grounded and sieved (50-100 mesh size) and washed with double distilled water. The resultant carbon was dried out and used as such for further studies.

Instrumentation for Characterization The surface structure of PSC particles was analyzed by scanning electron microscopy model (SEM, LEO-450, England) at 1500 magnification The presence of functional groups were observed by Fourier transform infrared spectroscopy (FTIR) in the range of 400-4000 cm-1 using FTIR Spectrophotometer model (Inter-spec 2020, spectrolab, UK) in KBr pellets. The concentration of Pb (II) ion in solution was analyzed using Atomic Absorption Spectrophotometer (AAS) model (GBC 902, Australia). The pH was measured by pH meter (Elico LI-120, India). The Elemental analysis of PSC was performed using EA1108 model (Carlo- Erba). The point of zero charge (PHz) (pHz) determines the surface charge, acidic and basic character of the adsorbent (Radovic 2008).

The 0.1M KCl solution was used for

determination of point of zero charge. The pH was adjusted between 2 to 12 by NaOH and HCl. 25 mL of 0.1M KCl solution and 0.05g adsorbent was added in 100 mL flask and left for 24 hrs. The final pH of the solution was measured. The graph was plotted between initial pH and final pH and the point of zero charge was observed (Sharma et al.2009)

Active sites determination The presence of active sites on the surface of the adsorbent was determined by acid base titration method. The presence of acid and basic groups were determined by using 25ml of 0.1N titrating solution such as NaOH, Na2CO3, NaHCO3 and 0.1g adsorbent in 100 ml standard flasks. The flasks were agitated at room temperature (30oC) in the shaker and left for 4-5 days. After 5 days, the agitated sample of volume 10 ml was titrated with 0.1N HCl solution to its neutralization point and the titration was done in triplicate.

Batch adsorption study Metal selective study The selective nature of PSC was studied for Pb (II), Cu (II), Ni (II), and Cd (II). PSC shows affinity for metal ion in the order of Pb> Cu> Cd> Ni. Therefore, on the basis of metal selectivity study, the Pb (II) ion was selected for detailed adsorption studies and as shown in Fig.3.

Kinetic study To study, solution pH, agitating time, initial concentration, temperature and dosage dose the batch experiments were conducted. For that 0.1g of adsorbent (PSC) was added to 50 mL metal ion solution of desired concentration (50 mgL-1 mg L-1) for 5 -180 min at 30 0C oC for 3hr and agitated at 120 rpm. The effect of pH was observed between pH 2-6 for 50 mgL-1 mg L-1 Pb(II) ion solution. The pH was adjusted using 0.1M HCl and 0.1M NaOH. After equilibrium, the sample was centrifuged and the final concentration of metal ion was determined by Atomic absorption spectrophotometer. The adsorption efficiency (%) and capacity (qe) of adsorbent were calculated from the following formula:

removal 

qe 

(Co  Ce )100 Ce

(Co  Ce)V W

(1)

(2)

where Co Where Co is the initial metal ion concentration (mgL-1) (mg L-1), Ce Ce is the final metal ion concentration (mgL-1) (mg L-1), W is the weight of the adsorbent (g), V is the volume of the metal ion solution (L).

Desorption To study desorption, 0.1g of adsorbent (PSC) was placed with 50 ml of metal ion solution of concentration 50 mgL-1. After 24 hrs of adsorption, the adsorbent was filtered and washed with double distilled water and contacted with various effluents like 0.1M HCl, 0.01M HCl, 0.1M EDTA, 0.1M Acetic acid of volume 50 mL for 3hr and then centrifuged. The supernatant was collected and analyzed by AAS.

Results and discussions Characterization of Pistachio shell carbon The SEM micrograph of the surface of PSC particles are shown in Fig.1, which shows porous nature with smooth surface occupied by lead particles species after adsorption. FTIR

spectra of PSC before and after adsorption of Pb(II) are shown in Fig .2 which shows the presence of functional groups in the adsorbent. The peak at 2362.7 cm-1 correspond to adsorption band of NH2 group and the peak at 2919.0 and 2822.7 cm-1 are assigned to symmetric and asymmetric –CH2 groups. The peak at 3202.0 to 3623.0 cm-1 correspond to – OH and –NH groups. The C-C stretching of aromatic rings of lignin are observed at 1511.0 cm-1(Sain et al.2006) and peak 1116.3 cm-1 is due to C-O bending. A shift in the peaks has been observed from 2850.0 to 2846.0 cm-1 and 2919.0 to 2979.8 cm-1 in the Pb (II) ion loaded adsorbent. The shift in the peak from 3251cm-1 to 3242.6 cm-1 shows the decrease in the intensity after adsorption. The shift in the peak from 2362.7cm-1 to 2340.2 cm-1 is due to the adsorption of Pb (II) ion. The changes in the functional groups like hydroxyl, amino groups, -CH2 group is due to surface complexation (Ngah et al. 2008). The elemental analysis of PSC was shown in Table 1. Based on the results in Table. 1, the carbon content in the PSC has significantly increased compared to the raw material due to high carbonization temperature. The nitrogen content was found to be zero. The decrease in hydrogen content was caused by its removal in the form of water during carbonization process. Determination of active sites and point of Zero charge The total number of acid sites like carboxylic, phenolic and lactonic were determined by the neutralization process using alkaline solutions of 0.1N NaOH, 0.1N NaHCO3 and 0.1N Na2CO3 (Ghodbane et al. 2008). The carboxylic and lactonic sites were obtained by titrating with 0.1N Na2CO3 solution and the Phenolic sites were determined by the difference. The concentration of various active sites is given in Table 2. The point of Zero charge when ∆pHz =0 is found to be 5.0 (Fig. 4(b)). Effect of contact time The effect of contact time was studied for 5 to 180 mints min at 30 0CoC at different concentration. The kinetics of PSC for Pb (II) ion adsorption was shown in Fig.4 which shows a very fast adsorption at first and then slows down. The equilibrium was attained in 180 min. and after this constant period the amount of metal ion adsorbed did not show any significant change with time. The uptake of metal ions on adsorbent shows that most of the reaction sites are exposed for the interaction with the metal ion. The presence of hydroxyl

groups on the adsorbent form a complex between the surface of the adsorbent and metal ion enhancing the faster rate of adsorption.

Effect of concentration The concentration effect for Pb (II) ion adsorption was studied in the concentration range of (20-100 mgL-1 mg L-1). At low metal ion concentration, adsorption capacity observed is low while with increase in concentration the adsorption capacity obtained increases. This effect is due to high driving force for mass transfer (Ayadin et al. 2008). At initial concentration, the metals were adsorbed to specific sites but as the concentration increase, the specific sites become saturated and exchange sites are completely filled.

Effect of pH The adsorption of metal ions is affected by the acidity of the solution. The acid medium affects the competition of H+ ion and metal ion for the active surface of the adsorbent (Gupta et al.2011). The pH effect was studied for the adsorption of Pb (II) onto Pistachia Vera L. at a pH range of 1-6 as shown in Fig. 5(a). As pH increases, the adsorption capacity also increases and maximum capacity of 24 mg g-1 was observed at pH 6. After pH 6, formation of soluble hydroxylated complexes of metal ion take place, so the study was conducted up to pH 6. At low pH value (pH<2.0), protons occupy most of the adsorbent sites and little Pb (II) could be sorbed because of electric repulsion with the protons of carbon.

Adsorbent dosage The study of adsorbent dosage was carried out at initial metal ion concentration of 50 mgL-1 mg L-1 with 0.05, 0.1, 0.2 and 0.4 g of adsorbent doses at pH 6. The results show as the dosage increases, the adsorption capacity decreases because the adsorption sites left remain unsaturated during the reaction (Dubey et al.2007).

Isotherms study The equilibrium adsorption isotherms are one of the most important parameter to understand the mechanism of adsorption. Langmuir, Freundlich, and Temkin isotherm were used to study adsorption process and constant parameters were calculated. The Langmuir, Freundlich and Temkin isotherm were expressed by following equation:

ce qm ce   qe b qm

ce c 1   e qe b.qm qm

(3)

1 log qe  log K f  log Ce n

(4)

qe  B1 ln kt  B1 ln ce

(5)

Where, qm is the monolayer adsorption capacity of adsorbent (mg g-1), b is the Langmuir constant ( L mg-1) which is related to free energy of adsorption. Kf(L g-1) and 1/n are the Freundlich constants and Kt is the equilibrium binding constant(Lmg-1). B1 is related to heat of adsorption. Langmuir, Freundlich and Temkin plots were shown in Fig 5(a,b.c) Fig 6(a,b,c) and the values obtained are given in the Table 3. The value of n and correlation coefficient (R²) predict the adsorption isotherm favorability and feasibility. The value of 1/n<1 shows the favorability and feasibility in intercept and R² are shown in Table 3. It is observed from the Table 3 that the high correlation coefficient (R²) shows the most favorable result for the adsorption of Pb (II) on PSC by Langmuir model.

Kinetics study To study the mass transfer and chemical reactions, pseudo 1st order, pseudo 2nd order and intraparticle diffusion models are used to determine the experimental data. The linearized rate of pseudo 1st order equation is given as (Ahmad et al.2012). log(qe  qt )  log qe 

k1t 2.303

(6)

Where k1 is the pseudo first order rate equation (min-1), qe is the adsorption capacity at equilibrium (mgg-1) (mg g-1) and qt is the adsorption capacity at time t (mgg-1) (mg g-1). k1 and R² of Pb (II) at different concentration are observed from the linear plot of log(qe-qt) vs t as shown in Fig.7(a) and given in Table 4. Pseudo second order kinetics was analyzed by using the linearized form of equation. t 1 t  qe2  qt k2 qe

(7)

Where qt is the adsorption capacity (mg g-1) at given time, qe is the adsorption capacity at equilibrium (mg g-1) and k2 is the pseudo second order rate concentration for adsorption (g mg-1 min-1). The k2, qe and regression coefficient value (R2) under different concentration were calculated from the linear plot of t/qt vs t as shown in Fig.6(b) Fig.7(b) and given in Table 4. The results were compared with the correlation coefficients (R2) value and shown in Table 4. The regression coefficient values for second order rate equation is high as compared to pseudo 1st order kinetics. Qe(exp) values of second order agreed well with qe(cal) value as compared to pseudo 1st order. The k2 value decreases as the Pb(II) ion concentration increases because at low concentration there is less competition for sorption sites. A similar phenomenon was also observed for Pb(II) on other natural adsorbent (Sun et al.2003; Li et al.2008; Chen et al.,2009; Amarsinghe et al.,2007). Therefore, it is concluded that adsorption system follows second order Kinetics. The intra-particle diffusion model (Gupta et al.2009) was considered for the adsorption of Pb (II) ion and it is given as: qt  kid t1/2  C

(8)

Where Kid (mg g-1 min-1/2) is the intraparticle diffusion rate constant As observed from Table 3, intercept value is greater than zero and it increases as concentration on lead ion increases on adsorption of PSC. The result observed shows that boundary layer diffusion is rate controlling step for the adsorption of Pb(II) ion on PSC and it is dominant when metal ion is higher. The C, Kid and R2 value were calculated from the plot of qt vs t1/2 and reported in Table 3.

Study of thermodynamics

The thermodynamic parameters were studied in the temperature range of 303-323K at temperature of 303, 313 and 323 K. The thermodynamic parameters such as enthalpy change

(∆H0 o), entropy change (∆S0 o) and Gibbs free energy change (∆G0 o) were estimated using the following equation (Kumar et al.2014).

kc 

cs ce

(9)

Where kc is the equilibrium constant, CS the solid phase concentration at equilibrium(mg L-1), Ce the equilibrium concentration of solution (mg L-1). G    RT ln kc

log Kc 

(10)

S  H   2.303R 2.303RT

(11)

∆H0 o and ∆S0 o were determined by Van’t Hoff equation: The values of ∆H0 and ∆S0 were obtained from the slope and the intercept of the plot log Kc vs. 1/T as shown in Fig.8 presented in Table 5. The values of ∆G0

o

are negative

confirming the adsorption of Pb (II) ion onto PSC is spontaneous and thermodynamically favorable at high temperature. The ∆G0 value for physiosorption is between -20 and 0 KJ Mol-1 while for chemisorption it is between -80 to -400 KJMol-1. The value of ∆H0 o obtained is in the range of physiosorption. The +ve value ∆H0

o

and ∆S0

o

indicate the

endothermic nature and the randomness at solid/liquid solution interface during the adsorption of Pb (II) respectively.

3.8 Desorption The desorption of Pb (II) ion from the PSC was carried out by using different effluent of 50 mL like HCl (0.1M,0.01M), Acetic acid (0.1M), EDTA (0.1M). It was observed that maximum 82.9% of Pb (II) ion could be desorbed by 0.1 M HCl solution as shown in Fig 9.

Adsorbent comparative Study To evaluate the feasibility and compare the adsorption capacity with other non conventional adsorbents, a comparative study is been shown in Table 5. It is proofed from the table that Pistachio Shell Carbon (PSC) has got the highest monolayer adsorption capacity of 7.19 mg g-1 among all other adsorbents. Conclusion The following conclusion can be stressed in the light of this work 

The uptake of lead at equilibrium by PSC was described by three models viz. (Langmuir, Frendluich and Temkin). The correlation coefficient (R²) shows that Frendluich and Temkin isotherm is best fitted to the data as compared to Langmuir.



The adsorption process follows the pseudo second order kinetics.



The intraparticle diffusion is the rate controlling step in this process.



The negative value of ∆G0 o indicates the feasibility and spontaneity of the adsorption process. The +ve value ∆H0 indicates the endothermic nature of adsorption. The +ve value of ∆S˚ reflects the affinity of PSC towards the Pb(II) ion.



82.9 % of Pb (II) could be desorbed by 0.1M HCl solution.

Acknowledgment Thanks are due to Maulana Azad National Fellowship (UGC) for providing financial assistance to Mrs. Shaziya H. Siddiqui in carrying out this work.

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Figure Captions: Figure 1 SEM micrograph of Pb(II) on PSC(a) before adsorption (b) after adsorption. Figure 2 FTIR Spectra for the adsorption of Pb(II) ion on PSC(a) before adsorption (b) after adsorption. Figure 3 Adsorption capacities of different metal ions on PSC Figure 4 Effect of contact time for the adsorption of Pb(II) on PSC Figure 5 (a) Effect of pH (b) point of zero charge for the adsorption of Pb(II) ion on PSC Figure 6 Isotherm modelling for the adsorption of Pb(II) ion on PSC (a) Langmuir (b) Freundlich (C ) Temkin Model Figure 7 Kinetic parameters for the adsorption of Pb(II) on PSC (a) Pseudo 1st order (b) Pseudo 2nd order

Figure 8 Thermodynamic parameters for the adsorption of Pb (II) ion on PSC Figure 9 Desorption of Pb(II) ion by various elluent on PSC

(a)

(b) Fig. 1

Fig. 2

30

25

24 20.5 qe

qe(mg/g)

20

16

15

12.5

10

5

0

Pb(II)

Cu(II) Cd(II) Metal ions Fig.3

Ni(II)

70 60 50 50 ppm

qe(mg/g)

40

100 ppm

30

150 ppm

20 10 0 0

50

100

time(min)

Fig. 4

150

200

30 25 20 15 10 5 0 0

2

4

6

8

pH 1.5

12

1

10

0.5

8

0

6 0

10

20

-0.5

4

-1

2 pHz

pHf

0

(a)

(b) Fig. 5 0.7 0.6 0.5

ce/qe

-1.5

0.4

30 oc

0.3

40 oc

0.2

50 oc

0.1 0 0

2

Ce 4

(a)

6

8

1.8 1.6 1.4 1.2 1 0.8 0.6

30 oc

0.4

40 oc

0.2

50 oc

0 0

0.2

0.4

0.6

0.8

1

log Ce

(b) 50 45 40 35 30

30 oc

25 20

40 oc

qe 15

50 oc

10 5 0 0

0.5

1

(c) Fig.6

1.5

2

1.6

50 ppm

1.4

100 ppm

1.2

150 ppm

1

log(qe-qt)

0.8 0.6 0.4 0.2 0 -0.2 0 -0.4

20

40

time(min)

(a) 10 50 ppm

8 6

t/qt 4 2 0 0

50

100

-2

150

200

time(min)

Fig.7 0.00335 0.0033 0.00325 0.0032 0.00315

log Kc 0.0031 0.00305 0.003 0.00295 1.5

1.55

1.6

1/T

Fig. 8

1.65

90 80 70 60 50 40

% des 30 20 10 0 0.1MHCl

0.01 M HCl 0.1 M EDTA 0.1MACo

Eluent

Fig.9 Table1: Elemental Analysis for the adsorption of Pb(II) ion on PSC S.no Element % composition before % composition after adsorption adsorption 1 Carbon 45.53 83.07 2 Hydrogen 5.56 1.84 3 Nitrogen 1.74 0

Table 2: Adsorbent active sites s.no Active sites 1 Acidic 2 Lactonic+carboxylic 3 Phenolic 4 Carboxylic 5 Basic

Concentration(mgL-1) 0.2 0.12 0.094 0.026 0.08

Table 3: Isotherm study for the adsorption of Pb(II) ion on PSC s.no Parameters 30 oC 40 oC 1 Langmuir Isotherm Qm 7.19 6.99 b -22.6 -0.44 -26.08 -0.53 R2 0.994 0.993

2

3

Freundlich Isotherm n Kf R2

50 oC

6.41 -26.59 -0.647 0.995

0.44 373.2 0.974

0.62 108.1 0.968

0.74 58.47 0.986

-41.66

-20.52

-13.42

Temkin Isotherm B1

Kt R2

6.55 0.9788

8.07 0.974

9.04 0.9796

Table 4: Kinetic study for the adsorption of Pb(II) ion on PSC s.no Parameters 50 mg L-1 100 mg L-1 1 Pseudo 1st order

2

3

150 mg L-1

Qe(cal) Qe(exp) k1 R2

12.07 19 0.094 0.854

15.45 49 0.103 0.869

31.47 65 0.184 0.999

Pseudo 2nd order Qe(cal) Qe(exp) k2 R2

20 20 4.59*103 0.999

50 49 -17.8*104 0.999

66.6 65 44.3*102 1

Intraparticle Diffusion C Kid R2

14.08 0.033 0.681

44.12 0.03 0.640

62.58 0.015 0.945

Table 5: Thermodynamic study for the adsorption of Pb(II) ion on PSC Temp (K) ∆Go(KJ/Mol K) ∆Ho(KJ/Mol) ∆So(KJ/ Mol) R2 5.47 0.047 0.936 303 -9.01 313 -9.52 323 -10.1

Table 6: Monolayer adsorption Capacity of Pb(II) ion on Various adsorbent

Adsorbent

Qmax(mg g-1)

Reference

Banana Peel

2.18

(Anwar et al.2010)

Acecia Nilolica

2.51

(Sadia et al. 2014)

Areca Waste

3.57

(Li et al. 2010)

Commercial

Activated 5.90

(Dubey and Shivani 2012)

Carbon Sawdust

6.54

(Yasemin and Zeiki . 2007)

Pistachio Shell Carbon

7.19

[Present Study]

Highlights 

PSC shows 12mgg-1 adsorption capacity towards Pb2+ ion at pH 6.



Best fitted by Langmuir isotherm and characterized by SEM, Elemental Analysis and FTIR



PSC was desorbed upto 82.9% by 0.1 M HCl.