Applicability of amethyst mining rejects as a novel photo-fenton catalyst for the abatement of an emerging pollutant in water

Abstract

For the first time, the applicability of amethyst mining rejects as a novel photo-Fenton catalyst was evaluated. Catalyst characterization was analyzed by scanning electron microscopy (SEM), X-ray diffraction (XRD), specific surface area (BET), and X-ray fluorescence (FRX). The effects of operating parameters, such as pH (2.0–4.0), catalyst dosage (0.25–1.0 g L−1), and H2O2 concentration (2.5–8.5 mmol L−1) on the degradation efficiency of Ponceau 4R dye were evaluated. The amethyst mining rejects presented a mesoporous structure, an average pore size of 9.73 nm, a specific surface area of 13.43 m2 g−1, and 23%wt of Fe2O3 on its chemical composition. The material showed an excellent catalytic efficiency, reaching 97.02% decolorization at 60 min and 75.40% TOC removal at 300 min, in the following reaction conditions: catalyst dosage: 0.75 g L−1, H2O2 concentration: 4.5 mmol L−1, and pH: 3. The waste also showed high stability and effectiveness after three successive reuse cycles. In addition, the catalyst was highly effective for treating synthetic wastewater composed of various hazardous dyes and salts.