Adsorption of Cr(VI) using α-Fe2O3 coated hydroxy magnesium silicate (HMS): isotherm, thermodynamic and kinetic study.

α-Fe₂O₃ coated hydroxy magnesium silicate (HMS) was prepared by the coprecipitation method and was used for the sorption of Cr(VI) from the aquatic environment. FT-IR, XRD, and SEM characterised the investigated composite. The influence of pH, shaking time, Cr(VI) concentration,and the temperature was investigated. The results obtained are fitted well with the pseudo-second-order kinetic model. Besides, Freundlich isotherm is adequate than the Langmuir isotherm. The adsorption was observed to be exothermic, spontaneous, and accompanied by increasing the system's randomness. The adsorption of chromium attained equilibrium after 60.0 min. The maximum adsorption capacities of α-Fe₂O₃/HMS composite for Cr(VI) were 10.75 mg/g obtained at a pH of 2. [ABSTRACT FROM AUTHOR]