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ABSTRACT
In the modern era, copper toxicity has become progressively more common due to widespread applications of copper in metallurgy, plumbing, transportation, and electrical wiring industries which demands the development of economic methods for removal of copper(II) ions from various industrial/domestic effluents before their disposal. In this study, nitrilotriacetic acid-modified Dendrocalamus strictus charcoal powder (NTA-MDCP) was prepared and applied as an adsorbent for the removal of copper(II) ions from aqueous solutions. Batch mode adsorption experiments were performed to achieve the optimum adsorption parameters such as pH = 6, contact time = 2 h, adsorbent dose = 2 g/L. The adsorption data were analyzed using Langmuir, Freundlich, and Temkin isotherm models. Maximum adsorption capacity of NTA-MDCP for copper(II) ions from Langmuir isotherms was found to be 142.86 mg/g which may be attributed to affinity of NTA present on the surface of adsorbent toward 1:1 and 2:1 complex formation with copper (II) ions in solution. Thermodynamic studies of adsorption of copper (II) ions indicated the spontaneous and endothermic nature of adsorption process which was confirmed by negative ΔG (= −15.309 to −23.995 kJ/mol) and positive ΔH (= +3.719 to +63.119 kJ/mol) values, respectively, while kinetic study revealed that the adsorption process followed pseudo-second order. Before and after adsorption, surface characteristics of NTA-MDCP were examined using scanning electron microscope-energy dispersive X-ray spectroscopy (SEM-EDX), Brunauer-Emmett-Teller (BET), carbon, hydrogen, nitrogen, and sulfur (CHNS) and X-ray diffraction (XRD) and the results obtained confirmed the accumulation of copper(II) ions on the surface of adsorbent. Regeneration of adsorbent was successfully carried out by the desorption process using calcium chloride solution (CaCl2: 5g/L). The present study revealed that NTA-MDCP could serve as a good adsorbent for the removal of copper(II) ions from aqueous solution certainly due to the chelating capacity of NTA.
Acknowledgements
The authors gratefully acknowledge the University Grants Commission for providing the financial support and University with Potential for Excellence (UPE) program. The first author is recipient of UGC-BSR fellowship under RFSMS scheme. We are also thankful to Central Department of Emerging Life Sciences, Guru Nanak Dev University, Amritsar for providing the necessary research facilities.
Conflict of interest
The authors declare that they have no conflict of interest.
Novelty statement
The present study pertains to evaluate the efficiency of NTA-MDCP to adsorb copper metal ions following different conditions of pH, metal ions concentration, adsorbent dose, contact time and temperature. Langmuir isotherms were found to be 142.86 mg/g which may be attributed to the affinity of NTA present on the surface of adsorbent towards 1:1 and 2:1 complex formation with copper (II) ions in solution. Before and after adsorption, surface characteristics of NTA-MDCP were examined using SEM-EDX, BET, CHNS, and XRD. Desorption studies for the regeneration of adsorbent were successfully carried out using calcium chloride (CaCl2: 5000 mg/L). The present study revealed that NTA-MDCP could serve as a good adsorbent for the removal of copper(II) ions from aqueous solution certainly due to the chelating capacity of NTA.