Sichuan University: Fe(III)/Fe(IV) Fenton-like process treats wastewater at neutral pH without iron sludge
Researchers at Sichuan University used Fe(III) hydrolysis to activate peroxymonosulfate, avoiding the acidic pH and iron sludge of conventional Fenton treatment.
A team from the State Key Laboratory of Hydraulics and Mountain River Engineering and the Sino-German Centre for Water and Health Research at Sichuan University (Chengdu, China) described a Fenton-like oxidation process that needs no acidic medium and produces no iron sludge. The authors are Shuo Chen, Yan Zhang, Shuang Meng, Peng Zhou and Bo Lai. The work was published in Nature Communications on 6 November 2026 nature.com
Nature Communicationsnature.comOpen source ↗. According to the authors, the process was developed for neutral conditions and used for the treatment of actual wastewater.
Fe(III) hydrolysis and peroxymonosulfate activation
The authors start from the limits of the conventional Fenton process built on the cyclic Fe(II)/Fe(III) pair. It works only in a strict acidic pH range and yields excessive iron sludge, because Fe(III) is reduced back to Fe(II) slowly.
Instead of forcing that reduction, the team used the intrinsic hydrolysis of Fe(III) to adjust its hydroxyl coordination. In this state Fe(III) activates peroxymonosulfate (PMS) and degrades contaminants. Theoretical and experimental results, the authors report, show that hydroxyl coordination speeds up electron transport from Fe(III) to PMS. This lowers the energy barrier for forming Fe(IV) and the sulfate radical at the same time.
Fe(III)/Fe(IV) cycle and process evaluation
Fe(IV) then oxidizes contaminants and returns to Fe(III). According to the authors, this Fe(III)/Fe(IV) redox couple sustains the reaction and leads to complete PMS decomposition nature.com
Nature Communicationsnature.comOpen source ↗. Because iron cycles between these two states, the process does not depend on Fe(III) reduction to Fe(II).
On this basis the group built a Fe(III)-cycled Fenton-like process that runs under neutral conditions. It was used to treat actual wastewater with no iron sludge output.
The authors also performed a techno-economic analysis and a life cycle assessment. They report that the results confirm better economic viability and environmental sustainability than the conventional Fenton process. The article presents the result as a strategy for water decontamination that is independent of acidic pH and free of iron sludge. The material does not give numerical values for degradation efficiency, reagent dose or cost.
