Efficient adsorbent for simultaneous removal of Cu(II), Zn(II) and Cr(VI): Kinetic, thermodynamics and mass transfer mechanism

Abstract

Present study deals with the development of a nano-porous adsorbent using neem bark for the simultaneous removal of Cu(II), Cr(VI) and Zn(II). The developed adsorbent is characterized using SEM, EDS and TGA. The effect of initial metal concentration, contact time, adsorbent dosage, temperature and pH are studied to see the performance of nANB for the metal ions removal. Various isotherm, kinetic and mass transfer models are validated with the experimental data and corresponding parameters are estimated. The maximum adsorption capacity of the developed adsorbent for Cu(II) and Zn(II) adsorption are found to be 21.23 and 11.904 mg g−1, respectively. The optimum parameter values for contact time, adsorbent dosage, temperature and pH are obtained as 48 h, 6 g L−1, 35 °C and 1.2, respectively, from the experimental results of Cu(II) and Zn(II) removal using nANB. The performance of nANB on the industrial effluent is evaluated by performing equilibrium batch experiments for the simultaneous removal of Cu(II), Cr(VI) and Zn(II) from an aqueous solution. The overall adsorption capacity of the nANB for the removal of multiple metal ions at 200 mg L−1 of each is obtained as 38.95 mg g−1 which is more than double for that obtained for individual metal ions.