Supporting of mixed ZnS–NiS semiconductors onto clinoptilolite nano-particles to improve its activity in photodegradation of 2-nitrotoluene

Abstract

Photodegradation of a 2-nitrotoluene (2-NT) aqueous solution was studied using ZnS–NiS supported onto clinoptilolite nano-particles (ZnS–NiS–NCP) and a Hg lamp as the radiation source. A planetary ball-mill was used for preparation of nano-particles of clinoptilolite (NCP). The photocatalyst was prepared via sulfiding of the Zn–Ni exchanged NCP and characterized by Fourier transformation infra red spectroscopy (FT-IR), X-ray diffraction (XRD), UV-Vis diffuse reflectance spectroscopy (DRS) and transmission electron microscopy (TEM). UV-Vis spectrophotometric measurements were performed for the determination of degradation and mineralization of the pollutant. Degradation of the pollutant was also confirmed by chemical oxygen demand (COD) and high performance liquid chromatography (HPLC). The optimal operation parameters were found to be: 0.75 g L⁻¹ of the ZnS_9.7%–NiS_3.0%–NCP catalyst and 55 ppm of 2-NT at pH 11. Unsupported ZnS and NiS showed smaller degradation activities than the supported one. The degradation process obeyed first-order kinetics.