Advanced oxidation processes (AOPs) are widely used to remove persistent organic contaminants from water, including residues from pharmaceuticals, personal care products, and pesticides. However, many conventional AOPs depend on sulfate radicals and hydroxyl radicals, which often require large oxidant inputs and may generate toxic intermediates before pollutants are fully mineralized. Non-radical pathways are therefore gaining attention because they may enable efficient pollutant removal with lower chemical demand and fewer unwanted byproducts. Still, designing catalysts that can selectively drive these pathways remains difficult. Given these challenges, further research is needed to develop oxygen-vacancy-engineered catalysts that can precisely regulate pollutant transformation pathways.

The study was conducted by researchers from Nanchang Hangkong University, Nankai University, and Beihang University, and was accepted for publication (DOI: 10.1016/j.ese.2026.100710) on May 27, 2026, in Environmental Science and Ecotechnology. The article reports that V_O-enriched manganese ferrite spinel (MnFe₂O₄) supported on carbon cloth can activate peroxymonosulfate (PMS) and steer phenol removal through a surface-confined direct oxidative transfer process (DOTP) rather than a conventional radical-dominated route.

The researchers prepared MnFe₂O₄/carbon cloth catalysts with tunable V_O concentrations by heat treatment under nitrogen. Structural tests confirmed that higher annealing temperatures increased defect density and altered the catalyst lattice. In phenol and PMS systems, the catalysts removed phenol completely within 55 minutes, while total organic carbon (TOC) removal increased with V_O content. Chemical oxygen demand (COD) analysis showed that a major fraction of organic carbon was transferred from solution to the catalyst surface, rather than simply degraded in the water phase. Surface analyses detected C–O and C–O–C bonds, supporting the formation of polymeric products such as polyphenylene ether. The team further validated the V_O-dependent structure–activity relationship in other oxide systems, including Mn₃O₄ and α-FeOOH. Mechanistic experiments and density functional theory (DFT) calculations showed that V_O sites promote electron delocalization, shift the d-band center upward, strengthen PMS and phenol chemisorption, and suppress radical generation. Together, these effects favor a two-electron transfer route and controlled polymerization.

The authors said the key advance is pathway control. By creating V_O, they said, the catalyst surface becomes a confined reaction platform where the oxidant and pollutant are brought together, electron transfer is directed, and polymer formation is favored over uncontrolled radical oxidation. They said this finding expands the role of defect engineering from simply improving catalytic activity to determining the chemical fate of pollutants during treatment. This provides a clearer design principle for building selective, stable, and lower-carbon catalytic systems for water purification.

The findings may support future treatment technologies that use less oxidant, reduce harmful intermediate formation, and remain stable under realistic water conditions. In a continuous-flow reactor, the optimized catalyst maintained 97.5% phenol removal and 73.2% TOC elimination over 240 hours, with limited metal leaching. It also performed well in tap water, river water, and secondary effluent, and removed other organic pollutants, including aniline, sulfamethoxazole (SMX), tetracycline (TC), bisphenol A (BPA), and rhodamine B (RhB). By linking V_O density to selective pollutant polymerization, the study offers a practical route toward more sustainable catalytic water purification.

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References

DOI

10.1016/j.ese.2026.100710

Original Source URL

https://doi.org/10.1016/j.ese.2026.100710

Funding information

This work was supported by the National Natural Science Foundation of China (Grant No. 52560010) and the Major Discipline Academic and Technical Leaders Training Program of Jiangxi Province, China (Grant No. 20232BCJ22015).

About Environmental Science and Ecotechnology

Environmental Science and Ecotechnology (ISSN 2666-4984) is an international, peer-reviewed, and open-access journal published by Elsevier. The journal publishes significant views and research across the full spectrum of ecology and environmental sciences, such as climate change, sustainability, biodiversity conservation, environment & health, green catalysis/processing for pollution control, and AI-driven environmental engineering. The latest impact factor of ESE is 14.3, according to the Journal Citation Reports^TM 2024.