Mechanisms of enhanced hexavalent chromium removal from water by bentonite stabilized zerovalent iron nanoparticles

Using natural bentonite as carrier, bentonite-supported nano zerovalent iron (B-nZVI) was prepared by liquid phase reduction method. The composite was characterized by X-ray diffraction, scanning electron microscopy, X-ray photoelectron spectroscopy, and the effect of Cr(VI) removal by B-nZVI was investigated. The results show that the agglomeration effect of nano zerovalent iron is reduced by bentonite loading, and the composite has the structural characteristics of two materials, which can effectively remove Cr(VI) from water. The removal rate of Cr(VI) increased with the decrease of pH and Cr(VI) initial concentration, and increased with the increase of B-nZVI composite dosage and reaction time. The removal rate of Cr(VI) by B-nZVI composite accorded with pseudo-second-order reaction kinetic model.