Impregnation of ZnO onto a Vegetal Activated Carbon from Algerian Olive Waste: A Sustainable Photocatalyst for Degradation of Ethyl Violet Dye

Abstract

This study is aimed at developing a simple and low-cost method to fabricate ZnO-loaded porous activated carbon (AC-ZnO) prepared from the Algerian olive-waste cakes and utilize it as a photocatalyst for the degradation of Ethyl Violet dye. The synthesized AC-ZnO material was characterized using powder X-ray diffraction, BET surface area measurements, Raman microscopy, thermogravimetric analysis, UV-visible diffuse reflectance spectroscopy, and zeta potential measurements. The degradation efficiency was evaluated with Ethyl Violet (EV) dye in aqueous solution under UV irradiation supplied by a Xenon arc lamp through a Pyrex glass filter (cutoff 280 nm), and the degraded products were identified by using electrospray ionization mass spectroscopy. Additional experiments were carried out under N 2 flow and with isopropyl alcohol to examine the role of superoxide and hydroxyl radicals, respectively. The amount of ● OH radical formed on irradiated AC-ZnO was tested with terephthalic acid which can act as a chemical trap for the ● OH radicals. The results from this study indicate that the AC-ZnO is a potential catalyst for the pollutant removal and the ● OH radicals are the key species for the degradation of EV. Further, this study opens up an opportunity to produce cheaper activated carbon support from olive wastes for environmental remediation applications.