2014/08/18 by Haizhou Liu, Thomas A. Bruton, Fiona M. Doyle +1 · 431 citations
Chemistry · Engineering · Environmental Science · #Advanced oxidation water treatment #Arsenic contamination and mitigation #Catalysis #Chemistry #Contamination #Decomposition #Environmental chemistry #Environmental remediation #Environmental remediation with nanomaterials #Geology #Groundwater #Groundwater remediation #Inorganic chemistry #Metal #Nuclear chemistry #Organic chemistry #Persulfate #Sodium persulfate #Sulfate
paper · pdf · doi:10.1021/es502056d
published in Environmental Science & Technology 48(17), 10330-10336 (American Chemical Society)
openalex publication_date 2014/08/18 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/01
Persulfate (S2O8(2-)) is being used increasingly for in situ chemical oxidation (ISCO) of organic contaminants in groundwater, despite an incomplete understanding of the mechanism through which it is converted into reactive species. In particular, the decomposition of persulfate by naturally occurring mineral surfaces has not been studied in detail. To gain insight into the reaction rates and mechanism of persulfate decomposition in the subsurface, and to identify possible approaches for improving its efficacy, the decomposition of persulfate was investigated in the presence of pure metal oxides, clays, and representative aquifer solids collected from field sites in the presence and absence of benzene. Under conditions typical of groundwater, Fe(III)- and Mn(IV)-oxides catalytically converted persulfate into sulfate radical (SO4(•-)) and hydroxyl radical (HO(•)) over time scales of several weeks at rates that were 2-20 times faster than those observed in metal-free systems. Amorphous ferrihydrite was the most reactive iron mineral with respect to persulfate decomposition, with reaction rates proportional to solid mass and surface area. As a result of radical chain reactions, the rate of persulfate decomposition increased by as much as 100 times when benzene concentrations exceeded 0.1 mM. Due to its relatively slow rate of decomposition in the subsurface, it can be advantageous to inject persulfate into groundwater, allowing it to migrate to zones of low hydraulic conductivity where clays, metal oxides, and contaminants will accelerate its conversion into reactive oxidants.