Synthesis, characterization of modified nanoadsorbents and its application in removal of Zn2+ ions from battery effluent

Abstract

The present study explored the feasibility of using the organically modified Nanokaoline (NK) and organically modified Nanobentonite (NB) for the effective removal of Zn2+ ions from battery effluent. The prepared NK and NB particles were characterized using FTIR and SEM analysis. The adsorption ability of NK and NB was optimized by varying parameters such as pH, adsorbent dosage, metal ion concentration and contact time. The maximum removal of Zn2+ ion was achieved by NK (93%) at an optimum condition of pH 6, for an initial metal ion concentration of 400 mgL−1, adsorbent dosage of 4 gL−1 with an equilibrium time of 70 min. Langmuir, Freundlich, Temkin, and Dubinin-Raushkevich isotherm models were tested with the experimental data. The maximum monolayer adsorption capacity was found to be 167 mgg−1 (NK) and 143 mgg−1 (NB), respectively. It was found that Freundlich isotherm best fits with the experimental results. The adsorption kinetics and mechanism were studied using pseudo-first order, pseudo-second order, Elovich, and intra-particle diffusion model and was found that the adsorption kinetics better fit with the pseudo-second order model. Various thermodynamic parameters such as ∆G°, ∆H°, ∆S°, have been analyzed and it has been found that the adsorption process was feasible, spontaneous and exothermic in nature. The overall results revealed that compared to NB, NK posed higher adsorption capacity and it could be utilized as an alternative and effective adsorbent for the removal of Zn2+ ions from battery effluent. Keywords: Adsorption, Nanokaoline, Nanobentonite, Zn2+ ions