Yang, X., J. Cai, X. Wang, Y. Li, Z. Wu, W.D. Wu, X.D. Chen, J. Sun, S.-P. Sun, and Z. Wang.
Environmental Science & Technology 54(6):3714-3724(2020)

Sand column tests were conducted to test bimetallic Fe-Mn oxide (BFMO) for peroxysulfate-based in situ chemical oxidation (ISCO) remediation of TCE using simulated (SGW) and actual groundwater (AGW). The sustained activity of BFMO, oxidant utilization efficiency, and postreaction characterization were investigated. Electron spin resonance (ESR) and radical scavenging tests implied that sulfate radicals (SO₄ ^•-) and hydroxyl radicals (HO ^•) played major roles in degrading TCE. In contrast, singlet oxygen contributed less to TCE degradation by BFMO-activated oxone. Fast degradation and almost complete dechlorination of TCE in AGW were obtained, with reaction stoichiometry efficiencies (RSE) of ΔTCE/ΔOxone at 3-5%, much higher than those reported RSE values in H2O2-based ISCO (≤0.28%). HCO₃^- did not show an effect on TCE degradation, and the effects of natural organic matters were negligible at high oxone dosage. Postreaction characterizations displayed that the BFMO was remarkably stable with sustained activity for oxone activation after 115 days of the continuous-flow test, and is a promising catalyst for oxone-based ISCO for TCE-contaminated groundwater remediation.