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An evaluation of the major factors influencing the removal of copper ions using the egg shell ( Dromaius novaehollandiae ): chitosan ( Agaricus bisporus ) composite

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ABSTRACT

Rapid industrialisation, technological development, urbanization and increase in population in the recent past coupled with unplanned and unscientific disposal methods led to increased heavy metal levels in water. Realizing the need for development of eco-friendly and cost effective methods, the present investigation was done for the adsorptive removal of copper from aqueous solutions with Dromaius novaehollandiae eggshell and chitosan composite. By one variable at a time method, the optimum contact time was found to be 60 min with an adsorbent dosage of 8 g/L at pH 6, initial adsorbate concentration of 20 mg/L and temperature 30 °C. The equilibrium data followed Langmuir and Freundlich isotherm models and pseudo second-order kinetics. The equilibrium adsorption capacity determined from Langmuir isotherm was 48.3 mg/g. From the Van’t Hoff equation, thermodynamic parameters such as enthalpy (ΔH°), entropy (ΔS°) and Gibb’s free energy (ΔG°) were calculated and inferred that the process was spontaneous, irreversible and endothermic. To know the cumulative effects of operating parameters, a three level full factorial design of Response Surface Methodology (RSM) was applied and the suggested optimum conditions were 7.90 g/L of adsorbent dosage, 20.2651 mg/L of initial adsorbate concentration and 5.9 pH. Maximum percentage of copper adsorption attained was 95.25 % (19.05 mg/L) and the residual concentration of the metal after sorption corresponded to 0.95 mg/L, which is below the permissible limits (1.3 mg/L) of copper in drinking water. The adsorbent was characterized before and after adsorption by SEM–EDS, FTIR and XRD. The FTIR analysis showed the involvement of carboxyl, hydroxyl and amino groups while XRD analysis revealed the predominantly amorphous nature of the composite post-adsorption and the peaks at 2θ angles characteristic for copper and copper oxide. The mechanisms involved in the adsorption of copper onto the adsorbent are chemisorption, complexation and ion exchange.

No MeSH data available.


a Pseudo-first order kinetics for adsorption of copper using DNES–CH composite. b Pseudo-second order kinetics for adsorption of copper using DNES–CH composite. c Intra-particle diffusion kinetics for adsorption of copper using DNES–CH composite
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Fig2: a Pseudo-first order kinetics for adsorption of copper using DNES–CH composite. b Pseudo-second order kinetics for adsorption of copper using DNES–CH composite. c Intra-particle diffusion kinetics for adsorption of copper using DNES–CH composite

Mentions: The pseudo-first order, pseudo-second order and intra-particle diffusion kinetic plots are given in Fig. 2a–c respectively. In the pseudo-first order, the K1 and qe values were 0.0582 (min−1) and 1.2103 (mg/g) respectively with a correlation coefficient (R2) of 0.9586. In the pseudo-second order, the K2 and qe values were 0.1104 (min−1) and 3.2362 (mg/g) respectively with a correlation coefficient (R2) of 0.9989. The intra-particle diffusion, a plot of solute sorbed against square root of contact time, should normally yield a straight line passing through the origin but the line in the present case, did not pass through the origin and the values of Kint and C were 0.1341 (mg/g min½) and 2.0427 (mg/g) respectively with a correlation coefficient (R2) of 0.8942. From the experiments, qe obtained was 3.1308 mg/g which is suggestive that the adsorption of copper by DNES–CH composite could be by chemisorption, appropriately explained by the pseudo-second order model.Fig. 2


An evaluation of the major factors influencing the removal of copper ions using the egg shell ( Dromaius novaehollandiae ): chitosan ( Agaricus bisporus ) composite
a Pseudo-first order kinetics for adsorption of copper using DNES–CH composite. b Pseudo-second order kinetics for adsorption of copper using DNES–CH composite. c Intra-particle diffusion kinetics for adsorption of copper using DNES–CH composite
© Copyright Policy - OpenAccess
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4764609&req=5

Fig2: a Pseudo-first order kinetics for adsorption of copper using DNES–CH composite. b Pseudo-second order kinetics for adsorption of copper using DNES–CH composite. c Intra-particle diffusion kinetics for adsorption of copper using DNES–CH composite
Mentions: The pseudo-first order, pseudo-second order and intra-particle diffusion kinetic plots are given in Fig. 2a–c respectively. In the pseudo-first order, the K1 and qe values were 0.0582 (min−1) and 1.2103 (mg/g) respectively with a correlation coefficient (R2) of 0.9586. In the pseudo-second order, the K2 and qe values were 0.1104 (min−1) and 3.2362 (mg/g) respectively with a correlation coefficient (R2) of 0.9989. The intra-particle diffusion, a plot of solute sorbed against square root of contact time, should normally yield a straight line passing through the origin but the line in the present case, did not pass through the origin and the values of Kint and C were 0.1341 (mg/g min½) and 2.0427 (mg/g) respectively with a correlation coefficient (R2) of 0.8942. From the experiments, qe obtained was 3.1308 mg/g which is suggestive that the adsorption of copper by DNES–CH composite could be by chemisorption, appropriately explained by the pseudo-second order model.Fig. 2

View Article: PubMed Central - PubMed

ABSTRACT

Rapid industrialisation, technological development, urbanization and increase in population in the recent past coupled with unplanned and unscientific disposal methods led to increased heavy metal levels in water. Realizing the need for development of eco-friendly and cost effective methods, the present investigation was done for the adsorptive removal of copper from aqueous solutions with Dromaius novaehollandiae eggshell and chitosan composite. By one variable at a time method, the optimum contact time was found to be 60 min with an adsorbent dosage of 8 g/L at pH 6, initial adsorbate concentration of 20 mg/L and temperature 30 °C. The equilibrium data followed Langmuir and Freundlich isotherm models and pseudo second-order kinetics. The equilibrium adsorption capacity determined from Langmuir isotherm was 48.3 mg/g. From the Van’t Hoff equation, thermodynamic parameters such as enthalpy (ΔH°), entropy (ΔS°) and Gibb’s free energy (ΔG°) were calculated and inferred that the process was spontaneous, irreversible and endothermic. To know the cumulative effects of operating parameters, a three level full factorial design of Response Surface Methodology (RSM) was applied and the suggested optimum conditions were 7.90 g/L of adsorbent dosage, 20.2651 mg/L of initial adsorbate concentration and 5.9 pH. Maximum percentage of copper adsorption attained was 95.25 % (19.05 mg/L) and the residual concentration of the metal after sorption corresponded to 0.95 mg/L, which is below the permissible limits (1.3 mg/L) of copper in drinking water. The adsorbent was characterized before and after adsorption by SEM–EDS, FTIR and XRD. The FTIR analysis showed the involvement of carboxyl, hydroxyl and amino groups while XRD analysis revealed the predominantly amorphous nature of the composite post-adsorption and the peaks at 2θ angles characteristic for copper and copper oxide. The mechanisms involved in the adsorption of copper onto the adsorbent are chemisorption, complexation and ion exchange.

No MeSH data available.