Solid waste derived montmorillonite clay as efficient photocatalytic system for removal of aquatic pollutants

Abstract

Accumulation of solid waste in the environment is a major concern to entire ecosystem and become a challenge to the scientific world. In this work, Bauxite derived solid waste (red mud) was used as a raw material for the synthesis of effective photocatalyst. Red mud was acid activated and pillared with montmorillonite (M−clay) in different molar ratio (RMM) through template assisted impregnation method and utilized for photo catalytic oxidation of phenol and reduction of Cr6+. From the XRD, the presence of hematite (α-Fe2O3) and goethite (α-FeOOH) in activated red mud was confirmed. The increased surface area, the pore size and pore volume of the composites compared to neat red mud and M−clay was shown by BET and BJH. The confirmation of visible light induced semiconducting behavior of the composites was established by UV-visible spectra. The suppression of electron-hole recombination plays a vital role in the photo catalytic applications confirmed by PL spectra. Electro chemical study emphasizes the formation of p-n hetero-junction and channelization of electron and hole through interface. Proper light harvestation, surface active sites, photo generated charge separation and reduced electron-hole recombination of RMM11 enhances photo oxidation efficiency of phenol (95%) and photo reduction of Cr6+ (97%) as compared to all other synthesized material.