Adsorptive removal of heavy metals from industrial effluents using cow dung as the biosorbent: Kinetic and isotherm modeling

Abstract

This article investigated an eco-friendly technique for the removal of heavy metals using biosorbent derived from cow dung. Heavy metals bearing wastewater were collected from a common effluent treatment plant located at Sangariya, Jodhpur (Rajasthan, India) to evaluate the removal efficiency of synthesized cow dung–activated carbon. The prepared activated carbon materials have a high surface area in the range of 948–1072 m2/g and also have significant quantities of micropore and mesopore volumes. Furthermore, pore diameters were in the range of 2.24–2.33 nm. Surface morphology was improved after being treated with NaOH. The adsorbent material was found to be an efficient medium for the removal of Cr(VI) and Cd(II). The results revealed that more than 95.6% of Cr(VI) and 66.88% of Cd(II) were achieved at the optimized condition of pH12.0, initial concentration of heavy metals 10 mg/L, 300 min of contact time, and the dose of 0.2 g/L, whereas only 16.3% removal efficiency was observed for Ni(II). Equilibrium data have been analyzed by Langmuir, Freundlich, Temkin, and Redlich and Peterson (R–P) isotherm models with the help of nonlinear regression analysis. Experimental data were best fitted for Freundlich and R–P isotherms. © 2020 Wiley Periodicals LLC