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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 FTIR spectrum of native DNES. b FTIR spectrum of native DNES–CH composite. c FTIR spectrum of copper loaded DNES–CH composite
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Fig8: a FTIR spectrum of native DNES. b FTIR spectrum of native DNES–CH composite. c FTIR spectrum of copper loaded DNES–CH composite

Mentions: The adsorption mechanism was investigated using FTIR analysis of the native DNES, native and the metal loaded DNES-CH composite in the range of 400–4000 cm−1 (Fig. 8a–c). The native DNES FTIR spectra showed sharp peaks at 874, 1418 cm−1 but after forming composite with chitosan, provided a number of functional groups which correspond to the amino and the carboxyl. In DNES-CH composite, ES is porous in nature and provides an efficient and strong support for the CH in forming the scaffold with more number of hydroxyl, carboxyl, amino and alcohol groups available to chelate the copper metal ions. FTIR spectra showed marked differences before and after adsorption of copper. Broadly, the spectrum could be divided into three distinct regions viz. 630–1000, 1180–3000, and 3300–3700 cm−1 wherein there are significant variations in the absorption patterns and the groups assigned for biosorption as given in Table 7.Fig. 8


An evaluation of the major factors influencing the removal of copper ions using the egg shell ( Dromaius novaehollandiae ): chitosan ( Agaricus bisporus ) composite
a FTIR spectrum of native DNES. b FTIR spectrum of native DNES–CH composite. c FTIR spectrum of copper loaded DNES–CH composite
© Copyright Policy - OpenAccess
Related In: Results  -  Collection

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

Fig8: a FTIR spectrum of native DNES. b FTIR spectrum of native DNES–CH composite. c FTIR spectrum of copper loaded DNES–CH composite
Mentions: The adsorption mechanism was investigated using FTIR analysis of the native DNES, native and the metal loaded DNES-CH composite in the range of 400–4000 cm−1 (Fig. 8a–c). The native DNES FTIR spectra showed sharp peaks at 874, 1418 cm−1 but after forming composite with chitosan, provided a number of functional groups which correspond to the amino and the carboxyl. In DNES-CH composite, ES is porous in nature and provides an efficient and strong support for the CH in forming the scaffold with more number of hydroxyl, carboxyl, amino and alcohol groups available to chelate the copper metal ions. FTIR spectra showed marked differences before and after adsorption of copper. Broadly, the spectrum could be divided into three distinct regions viz. 630–1000, 1180–3000, and 3300–3700 cm−1 wherein there are significant variations in the absorption patterns and the groups assigned for biosorption as given in Table 7.Fig. 8

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.