Novel Zinc ferrite composite with starch and carboxy methyl starch from biowaste precursor for the removal of Ni (II) ion from aqueous solutions

Abstract

In the present work, Zinc ferrite composites with Mango starch (MS) and carboxymethyl mango starch (CMMS) were synthesized for the removal of Ni (II) ions from aqueous solutions. Composites prepared were characterized by Fourier Transform Infrared (FTIR) Spectroscopy, X-Ray Diffraction (XRD) analysis, pH of point zero charge (pHzpc), Scanning Electron Microscopy (SEM), and BET. Batch adsorption technique was used to study effect of various parameters such as pH, adsorbent dose, contact time, concentration, and temperature for removal of Ni (II) ions from aqueous solutions. The optimum time, pH, adsorbent dose and temperature required for ZFN@ MS and ZFN@ CMMS in this study was 110 min., 7 & 8, 0.1 g and 308 K, respectively. Out of various adsorption isotherms, Freundlich isotherm model fitted best with adsorption data. Maximum adsorption capacity for removal of Ni (II) were found to be 65.3 and 208.3 mg/g, respectively by using Zinc ferrite@ MS and Zinc ferrite@ CMMS adsorbents. Lagergren Pseudo second order model best fitted with results which indicated that the process of adsorption was chemical in nature. The value of adsorption energy for ZFN@ MS was 50 kJ/mol and for ZFN@ CMMS, it was 31.62 kJ/mol. Thermodynamic study revealed that process was endothermic and non-spontaneous in nature. Regeneration studies were conducted for five cycles where Zinc ferrite@ MS showed 71% regeneration efficiency and Zinc ferrite@ CMMS showed 78% regeneration efficiency for nickel ion removal from aqueous solution.