Visible light-driven LaFeO3-biochar composites for removal of sulfamethoxazole by enhanced electron transfer coupled with peroxymonosulfate

Abstract

In this study, we prepared a novel biochar and LaFeO3-bonded nanosphere composite (LFBC) using a co-precipitation-pyrolysis method for the degradation of sulfamethoxazole (SMX). Under visible light conditions, LFBC-activated peroxymonosulfate (PMS) completely removed SMX within 25 min with rate constants 23 and 59 times higher than those of LaFeO3 and biochar, respectively. Both free radical and non-free radical pathways participated in the SMX degradation process, with the non-free radical pathway playing a primary role. It is noteworthy that the interaction between LaFeO3 and Biochar facilitated electron transfer and active sites, promoted the redox cycle of Fe3+/Fe2+, and greatly enhanced the catalytic performance of the composites. Degradation pathway and toxicity evaluation of pollutant removal processes in LFBC/PMS/vis systems based on intermediate identification and Fukui function calculations. This work proved the excellent synergistic performance of LFBC in light utilization and PMS activation, providing a potential utilization for efficient treatment of antibiotic wastewater and antibiotic-resistant bacteria.