Synthesis, characterization and adsorptive performances of functionalized clay minerals and red mud for aqueous arsenic removal

Water pollution due to elevated arsenic (As) levels is a very serious health issue worldwide. Employing adsorbent substances to remove As from an aqueous environment presents a viable solution to this pressing concern. The As adsorption behavior onto modified clay (kaolinite, bentonite) and red mud in aqueous media was investigated in this study. Specific surface area (SSA), X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), and transmission electron microscopy (TEM) studies confirmed successful modification of kaolinite, bentonite, and red mud through Fe-impregnate and dimethyl sulfoxide (DMSO)intercalation. The incorporation of iron and DMSO improved the ability to remove As. The kinetic study showed that the adsorption equilibrium for both clay minerals and red mud products was reached within approximately 120 min, and the data fitted well to the simple Elovich, power function, and pseudo-second-order equation. Of all the products, Fe-Bentonite exhibited the highest As adsorption capacity, with a value of 581.2 mu g g-1 (initial As concentration = 50 mu g mL-1). Revealed in this study is that Fe-Bentonite, DMSO-Bentonite, and Fe-Red mud were the best-screened products for removing As from the aqueous system.