Fe@Fe2O3 core-shell nanowires compounding humic acid enhanced catalysis removal 2,4,6-trichlorophenol: Performance and mechanism

• Humic acid enriches functional groups and surface oxygen vacancies of Fe@Fe 2 O 3 . • Fe@Fe 2 O 3 compounding humic acid had a wider pH range for degrading TCP. • Activity stability and cyclicality of Fe@Fe 2 O 3 is improved by compounding humic acid. • Humic acid promoted Fe@Fe 2 O 3 to release iron ions and accelerated Fe 3+ reduction. In this study, compounding Fe@Fe 2 O 3 with humic acid (HA) enhanced peroxymonosulfate (PMS) activation to degrade 2,4,6-trichlorophenol (TCP). The characterization and catalytic performance of the materials revealed that Fe@Fe 2 O 3 -HA had more functional groups, more surface oxygen vacancies, higher stability, and higher cyclicality. HA promoted the continuous release of iron ions as well as the process of PMS activation by accelerating Fe 3+ reduction. The results of electron paramagnetic resonance (EPR) and quenching experiments indicated that more reactive oxygen species (ROS) were generated in the Fe@Fe 2 O 3 -HA/Fe 2+ /PMS system, and SO 4 − was the dominant ROS for TCP degradation. The degradation efficiency of TCP in the Fe@Fe 2 O 3 /Fe 2+ /PMS system was increased from 59% to 83% within 10 min after HA was compounded. The degradation efficiency of TCP in the Fe@Fe 2 O 3 -HA/Fe 2+ /PMS system was greatest at 60 min under alkaline conditions. Thus, our results demonstrated that Fe@Fe 2 O 3 -HA, a highly active catalyst exhibited excellent reactivity in the potential application of Fe 2+ /PMS for groundwater protection.