Photocatalytic activity of mont-La (6%)-Cu0.6Cd0.4S catalyst for phenol degradation under near UV visible light irradiation

Abstract

A mont-La (6%)-Cu0.6Cd0.4S nanocomposite was prepared by a simple cation exchange and impregnation method and its application for the phenol removal from wastewater was studied. The photocatalyst was characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (XEDS) and UV–vis diffuse reflectance spectroscopy (UV–vis DRS). Phenol in aqueous solution was used as a model compound for evaluation of near UV–vis (filter cut-off for λ≥366nm) photocatalytic activity. We have studied the following parameters: load of photocatalyst, load of phenol, pH, [O2], and irradiation wavelength. Within 240min, heterogeneous suspensions of 1g·L−1 of mont-La (6%)-Cu0.6Cd0.4S nanocomposite allowed removal of ca. 86% of 20mg·L−1 solution of phenol at pH=5.44, with dissolved oxygen from air, with 77.8% TOC removal. The kinetics of photocatalytic transformation followed the Langmuir–Hinshelwood kinetic model. Pseudo-first-order kinetics adequately fitted the experimental data and the obtained rate constants are reported. With the mont-La (6%)-Cu0.6Cd0.4S catalyst 84% removal of phenol degradation efficiency was achieved after five consecutive photocatalytic cycles. Twelve main photoproducts were observed from phenol photodegradation, using HPLC–MS. The used photocatalyst is promising for green chemistry use in abatement of persistent organic pollutants.