Discovery of vanadium titano-magnetite as a persulfate activator for 2,4-dinitrotoluene degradation: Availability and mechanism

Abstract

Persulfate was activated with vanadium titano-magnetite to degrade dinitrotoluene (2,4-DNT) for the first time, according to an investigation. The vanadium titano-magnetite/persulfate system was found to have a high degradation efficiency for 2,4-DNT in new findings. The experiments were conducted to determine the influence of pH and inorganic anions (Cl−, NO3−, and HCO3−) on the breakdown of persulfate. OH is the dominant radical for the degradation of 2,4-DNT. The repeatability test for the material showed that vanadium titano-magnetite still had high activity after repeated utilization, and the efficiency for 2,4-DNT degradation was reduced by 15.6 % in four consecutive experiments, which confirmed the sustainability and recyclability of the catalyst. The elucidation of persulfate activation reveals that Fe(II) provides electrons through an oxidation reaction. This encourages the formation of SO4− from S2O82− and the subsequent generation of OH to break down contaminants. Furthermore, an oxidation reaction may occur with V(III)/V(IV)/V(V), which promotes the reduction of Fe(III) to Fe(II). The vanadium titano-magnetite system's rapid electron transfer leads to the cyclic interconversion of Fe(II)/Fe(III) and facilitates the degradation of 2,4-DNT, and its degradation products go a step further classified as 2,4-dinitrobenzyl alcohol, 2,4-dinitrobenzaldehyde, and p-nitrobenzoic acid. These findings may offer a fresh perspective on the interaction between natural vanadium-containing minerals and persulfate, and provide a cost-effective persulfate activator for reducing contaminants.