Carbocatalysts for Enhancing Permanganate Oxidation of Sulfisoxazole

Abstract

Permanganate (Mn(VII)) is extensively applied in water purification due to its stability and ease of handling, but it is a mild oxidant for trace organic contaminants (TrOCs). Hence, there is significant interest in strategies for enhancing reaction kinetics, especially in combination with efficient and economical carbocatalysts. This study compared the performance of four carbocatalysts (graphite, graphene oxide (GO), reduced-GO (rGO), and nitrogen-doped rGO (N-rGO)) in accelerating sulfisoxazole (SSX) oxidation by Mn(VII) and found that GO exhibited the greatest catalytic performance. Besides, the Mn-(VII)/GO system shows desirable capacities to remove a broad spectrum of TrOCs. We proposed that the degradation of SSX in Mn(VII)-GO suspensions follows two routes: (i) direct oxidation of SSX by Mn species [both Mn(VII) and in situ formed MnO 2(s) ] and (ii) a carbocatalyst route, where GO acts as an electron mediator, accepting electrons from SSX and transferring them to Mn(VII). We developed a mathematical model to show the contribution of each parallel pathway and found one-electron transfer is primarily responsible for accelerating SSX removal in the Mn(VII)/GO system. Findings in this study showed that GO provides a simple and effective strategy for enhancing the reactivity of Mn(VII) and provided mechanistic insights into the GO-catalyzed redox reaction between SSX and Mn(VII).

Efficient Removal of Antimony(V) from Antimony Mine Wastewater by Micrometer Zero-Valent Iron

“…To enhance the removal efficiency of mZVI-A, it is possible to accelerate its electron transfer process by incorporating external carbon materials. Various carbon materials are available for this purpose, including biochar, − carbon nanotubes, , graphene oxide, , among others.…”

Enhanced removal of As(iii) by manganese-doped defective UiO-66 coupled peroxymonosulfate: multiple reactive oxygen species and system stability

“…Although the triplet peak signal corresponding to the TEMP-1 O 2 adducts was detected, it appeared that 1 PMSO could be targeted to react with high-valent metals to form PMSO 2 leading to PMSO depletion. 71 Therefore PMSO was selected as a probe for high-valent Mn to find out whether high-valent Mn contributes to As(III) oxidation, and the experimental results are shown in Fig. S17.…”

New Insights into the Combination of Permanganate and Hydrogen Peroxide as a Novel Oxidation Process for Enhanced Removal of Organic Contaminants

“…12,13 For instance, Zhang et al focused on the ruthenium-loaded catalysts and found that they could promote the reaction between Mn(VII) and TrOCs by generating higher metallic valent states (e.g., Ru(VI) and Ru(VII)). 14,15 Recent reports demonstrated that carbonaceous catalysts (e.g., carbon nanotubes, 16 graphite, 17 graphite oxide, 18 reduced graphene oxide, 19 and biochar 20,21 ) could enhance the degradation of TrOCs by Mn(VII) via mediating the electron transfer and/or generating reactive manganese species (RMnS) (e.g., Mn(VI) and Mn(V)). Some soluble redox mediators (e.g., 2,2′-azino-bis(3-ethylbenzothiazoline)-6-sulfonate (ABTS) and 9-azabicyclo[3.3.1]nonane N-oxyl (ABNO)) can act as the electron shuttles to catalyze the TrOC degradation by Mn(VII).…”

“…In recent years, various strategies have been proposed to enhance the oxidation of TrOCs by Mn­(VII), where different mechanisms are involved. , For instance, Zhang et al focused on the ruthenium-loaded catalysts and found that they could promote the reaction between Mn­(VII) and TrOCs by generating higher metallic valent states (e.g., Ru­(VI) and Ru­(VII)). , Recent reports demonstrated that carbonaceous catalysts (e.g., carbon nanotubes, graphite, graphite oxide, reduced graphene oxide, and biochar , ) could enhance the degradation of TrOCs by Mn­(VII) via mediating the electron transfer and/or generating reactive manganese species (RMnS) (e.g., Mn­(VI) and Mn­(V)). Some soluble redox mediators (e.g., 2,2′-azino-bis­(3-ethylbenzothiazoline)-6-sulfonate (ABTS) and 9-azabicyclo[3.3.1]­nonane N -oxyl (ABNO)) can act as the electron shuttles to catalyze the TrOC degradation by Mn­(VII). , Our group showed that several ligands (e.g., pyrophosphate, EDTA, and humic acid) could stabilize Mn­(III) species formed in situ upon Mn­(VII) reduction, resulting in a significantly enhanced oxidation of bisphenol A at a relatively low solution pH of 5.0–6.0 .…”