Quantitative analysis on the mechanism of Cd2+ removal by MgCl2-modified biochar in aqueous solutions

In this study, a pristine biochar (BC) and MgCl2-modified (MBC) were prepared using Pennisetum sp. straw for removing Cd2+ from aqueous solutions. Scanning electron microscope (SEM) imaging combined with energy dispersive X-ray spectroscopy (EDX), photoelectron (XPS), Fourier transform infrared (FTIR), as well the surface area porosity analyses used to reveal physico-chemical characteristics of modified adsorbents. Results suggested that MgCl2 impregnation during synthesis had enhanced specific pore volume biochar. Batch adsorption experiments indicated data MBC fitted Langmuir isothermal pseudo-second order kinetic models, indicating chemical was undergoing in system. The maximum capacity on 763.12 mg/g, which 11.15 times higher than BC. removal by mainly attributed mechanisms an order: Cd(OH)2 precipitation (73.43%) > ion exchange (22.67%) Cd2+-? interaction (3.88%), negligible contributions functional group complexation, electrostatic attraction physical adsorption. could thus be promising adsorbent