Fe-Ti bimetals catalyst derived from biowaste for highly efficient persulfate activation: Performance and mechanisms

Abstract

Sludge based catalysts (SBCs) has been considered as a promising and viable approach to sludge reclamation. Herein, we fabricated bimetallic Fe-Ti doped SBCs via a facile synthesis with sludge containing polyacrylamide (PAM) as N-precursor. The adsorption capacity and degradation efficiency of as-synthesized SBCs were assessed using tetracycline (TC) as a target pollutant, in which PAM in sludge played a dual role by promoting porosity, active sites, and structural defects beneficial for persulfate (PS) activation. Fe-Ti doping induced the activation of PS by a fast redox cycle of Fe3+/Fe2+ associated with the coexistence of Ti4+/Ti3+, which enabled an efficient electron transfer between the catalyst and PS. The synergistic effect of PAM-derived N doping and Fe-Ti bimetals resulted in prevention of iron leaching and enhanced catalyst stability over a wide pH range. The surface SO4•− was the primary oxidant in the TC degradation process based on free-radical quenching experiments, and degradation pathways of TC were proposed given the intermediate evidence from UPLC-HRMS analysis. This study promotes the reclamation of PAM-containing sludge providing an eco-friendly and efficient process to activate PS for wastewater treatments.