A novel strategy for enhancing heterogeneous Fenton degradation of dye wastewater using natural pyrite: Kinetics and mechanism

Hydrogen peroxide activation by pyrite for degradation of recalcitrant contaminants receives increasing attention. The improvement of catalytic efficiency of natural pyrite is still a challenging issue. This work provides a novel strategy of enhancing catalytic efficiency via pre-reaction between pyrite and hydrogen peroxide. Effects of process factors including pre-reaction time, hydrogen peroxide, solution pH and initial dye concentration were examined. Natural pyrite with low purity was characterized by Raman, scanning electron microscopy, X-ray diffraction, and X-ray photoelectron spectroscopy. Reaction kinetic verifies tremendous improvement of the reaction rate through pre-reaction. Enhanced dye degradation is ascribed to hydroxyl radical production promoted by self-regulation of pH, Fe2+ releasing and Fe2+/Fe3+ cycle. The plausible mechanism was proposed based on multiple determinations. Dye degradation in different water matrix was efficiently obtained, as well as multicomponent dyes. Additionally, broad operation pH and good reusing performance make the developed process highly attractive for application. This work provides a solid step-forward of pyrite/hydrogen peroxide Fenton process for treatment of recalcitrant contaminants in wastewater. (C) 2021 Elsevier Ltd. All rights reserved.

Automated summary

This study enhances the catalytic efficiency of pyrite by pre-reaction with hydrogen peroxide to degrade recalcitrant contaminants. By optimizing factors such as pre-reaction time, hydrogen peroxide concentration, solution pH, and dye concentration, efficient degradation of contaminants using natural pyrite was achieved. Enhanced dye degradation was attributed to the production of hydroxyl radicals facilitated by self-regulation of pH, Fe2+ release, and Fe2+/Fe3+ cycle.