Adsorptive Removal of Cu(II) Ions from Aqueous Media onto 4-Ethyl Thiosemicarbazide Intercalated Organophilic Calcined Hydrotalcite

This paper describes the adsorption properties of Cu(II) ions from aqueous media by 4-ethyl thiosemicarbazide (ETSC) intercalated organophilic calcined hydrotalcite (OHTC). Elemental analysis, X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), and thermogravimetric-differential thermogravimetric (TG/DTG) studies have helped in characterizing the adsorbent. The effects of various factors like adsorbent dose, pH, initial concentration, and contact time were studied. The pH study indicated that Cu(II) has a good adsorption potential at pH 5.5. The adsorption of metal ion remained constant after 4 h. The pseudo-second-order model was the best fit to describe the adsorption kinetics. The FTIR spectroscopy revealed that both amino and thiocarbonyl groups in ETSC-OHTC are responsible for Cu(II) removal. The Freundlich model described the adsorption results very well, and the K-F value was found to be 21.38 at 303 K. Electroplating industry wastewater was used to test the adsorption efficiency toward Cu(II) removal. The recovery (similar to 95.0 %) of Cu(II) ion from the loaded adsorbent was possible with 0.01 mol.kg(-1) HCl solutions. Many successive adsorption/desorption cycles were achieved without any noticeable change in the adsorption capacity.