CHEMICAL SCIENCE

A new strategy for regulating the reaction pathway of zinc-iron dioxide Fenton catalysts by visible illumination


A new strategy for regulating the reaction path of zinc-iron dioxide Fenton catalysts by visible light exposure proposed by Dalian Chemical Institute

Recently, Wang Junhu’s team, a researcher in the Energy Research Technology Platform Moorsbauer Spectroscopy Research Group, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, realized the effective regulation of the reaction mechanism of zinc-iron dioxide-like Fenton catalysts through visible light, which provided a new strategy for the transformation of the reaction path of heterogeneous catalysts from free radicals to non-radicals in Fenton-like reactions.

The quenching of free radicals in Fenton-like reactions by various inorganic anions or high concentrations of organics limits their value in industrial applications. Non-radical-dominated systems can effectively overcome these limitations and show high activity against the degradation of pollutants under the interference of widely present aquatic substrates. Therefore, the development of inexpensive, environmentally friendly non-radical-dominated Fenton-like catalysts is one of the research priorities.

In this work, a series of Zn-Fe dioxides were prepared by calcining Zn1-xFex-Fe Prussian blue analogues in an ambient atmosphere. Through the Mössbauer spectrum combined with various other routine characterizations, it was revealed that samples ZFO-1 and 4 were composed of nanocomposite ZnFe2O4 and ZnO, while ZFO-2 and 3 were composed of ZnFe2O4 and Fe2O3. It was found that Zn-Fe dioxides leached only trace amounts of iron under the conditions of visible light and peroxide monosulfate (PMS) coexistence, as well as in high concentrations of natural organic humic acid, various inorganic ions and simulated actual wastewater systems, showing excellent catalytic performance for the oxidative removal of various organic pollutants. Under visible light, Zn-Fe dioxides showed different performance from previous Fenton-like catalysts with free radical mechanisms, and showed good resistance to various ions and humic acids, indicating that visible light played an important role in the occurrence of Fenton-like reactions.

The above comparative experiments, free radical capture experiments and electron paramagnetic resonance spectroscopy results show that light-induced electrons and holes can trigger the efficient activation of PMS, thereby changing the reaction path from a radical-dominated pathway under obscura conditions to a singlet oxygen(1O2)-dominated non-radical pathway on Zn-Fe dioxide. This work provides a new strategy for modulating radical and non-radical pathways in advanced PMS-based oxidation processes using solar energy.

The related research results are titled Modulation of reaction pathway of Prussian blue analogues derived Zn-Fe double oxides towards organic pollutants oxidation, published in Chemical Engineering Journal. The research work is supported by the National Natural Science Foundation of China and the International Partnership Program of the Chinese Academy of Sciences. (Source: Dalian Institute of Chemical Physics, Chinese Academy of Sciences)

Related paper information:https://doi.org/10.1016/j.cej.2022.140103

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