Insights into the Electron-Transfer Mechanism of Permanganate Activation by Graphite for Enhanced Oxidation of Sulfamethoxazole

Abstract

Many reagents as electron sacrificers have been recently investigated to induce decomposition of permanganate (KMnO 4 ) to produce highly reactive intermediate Mn species toward oxidation of organic contaminants; however, this strategy meanwhile causes low KMnO 4 utilization efficiency. This study surprisingly found that graphite can mediate direct electron transfer from organics (e.g., sulfamethoxazole (SMX)) to KMnO 4 , resulting in high KMnO 4 utilization efficiency, rather than reductive sites of graphite-induced conversion of KMnO 4 to highly reactive intermediate Mn species. The galvanic oxidation process (GOP) and comparative experiments of different organic contaminants prove that the KMnO 4 /graphite system mainly extracts electrons from organic contaminants via a one-electron pathway instead of a two-electron pathway. More importantly, the KMnO 4 /graphite system has superior reusability, graphite can keep a long-lasting reactivity, and the KMnO 4 utilization efficiency elevates significantly after each cycle of graphite. The transformation of SMX in the KMnO 4 /graphite system mainly includes self-coupling, hydroxylation, oxidation, and hydrolytic reaction. The work will improve insights into the electrontransfer mechanism and unveil the advantages of efficient KMnO 4 utilization in the KMnO 4 -based technologies in environmental remediation.

Evaluation of N-doped carbon for the peroxymonosulfate activation and removal of organic contaminants from livestock wastewater and groundwater

“…According to the theory of the Fukui function on nonradical oxidation processes, the local descriptors of f + and f − were adopted to distinguish the most vulnerable sites with respect to the nucleophilic and electrophilic reactions, respectively. 47…”

Recent advances in metal-free catalysts for the remediation of antibiotics, antibiotic resistant bacteria (ARB), and antibiotic resistant genes (ARGs)

“…Notably, when BC and KMnO 4 were injected into sulfamethoxazole solution, sulfamethoxazole could be rapidly and effectively removed within 30 min (97%). Likewise, Peng et al 288 reported that with the assistance of graphite, the oxidation ability of KMnO 4 -based AOPs would be boosted. In their study, the graphite mediated one-electron transfer from sulfamethoxazole to KMnO 4 led to high KMnO 4 utilization efficiency.…”

“…Notably, when BC and KMnO 4 were injected into sulfamethoxazole solution, sulfamethoxazole could be rapidly and effectively removed within 30 min (97%). Likewise, Peng et al 288 reported that with the assistance of graphite, the oxidation ability of Fig. 13 Second-order rate constants (k) for reactions of various antibiotics and commonly used quenching agents with ROS (i.e., cOH, SO 4 c À , 1 O 2 , and Clc).…”

“…In addition, the highest occupied molecular orbital could also reflect the active sites of antibiotics. Peng et al 288 proposed that the highest occupied molecular orbital of sulfamethoxazole was mainly located on the side with benzene rings, in which it was easier for electrons to escape, and thus they would be easily attacked. Notably, the degradation pathways of antibiotics might be quite distinct in different carbon-induced AOPs.…”

Degradation of Diclofenac in Urine by Electro-Permanganate Process Driven by Microbial Fuel Cells

“…In recent years, advanced oxidation processes (e.g., Fenton technology [11], Fenton-like technology [12], ozone oxidation technology [13], permanganate oxidation technology [14], and photocatalytic technology [15]) have attracted considerable attention from researchers as methods for the degradation of such bio-refractory organic pollutants. In particular, permanganate oxidation technology has been widely utilized for the elimination of organic pollutants due to its advantages as a low-cost, easily transportable, and environmentally friendly methodology [16]. However, the stability of permanganate (PM, E 0 = 1.68 eV) and its low potential relative to radicals [17] to a certain extent limit its reactivity to organic pollutants.…”