Cellulose hydrogel coated nanometer zero-valent iron intercalated montmorillonite (CH-MMT-nFe0) for enhanced reductive removal of Cr(VI): Characterization, performance, and mechanisms

Abstract

Cellulose hydrogel coated nanometer zero-valent iron intercalated montmorillonite (CH-MMT-nFe0) was innovatively designed and fabricated, and applied for the removal of Cr(VI). The composite was characterized with scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS). The addition of MMT and CH improved the dispersity, oxidation resistance and stability of nFe0, and the removal rate of Cr(VI) was up to 98%. At the same time, the interlayer limit of montmorillonite reduced the particle size of nFe0 and increased the activity of nFe0. The formation of “micro reactor” between montmorillonite and iron surface promoted the adsorption and degradation of Cr(VI). Hydrogels had good mesoporous network structure and functional groups such as amides and carboxylic acids. They provided.additional active sites and promoted mass transfer. The multiple interaction mechanisms of CH– MMT-nFe0 on Cr(VI), such as adsorption, reduction and co-precipitation were realized. The material was a potential Cr(VI) polluted wastewater remediation material.