Activated carbon fiber mediates efficient activation of peroxymonosulfate systems: Modulation of manganese oxides and cycling of manganese species

Manganese oxides show a strong catalytic activity in the peroxymonosulfate (PMS) advanced oxidation process but have poor chemical stability and a propensity to cause the aggregation of nanoparticles. Here, a novel composite material (abbreviated as MnOx@ACF) was synthesized, characterized, and applied. Activated carbon fiber (ACF) was selected as a carrier, which modulated the composition of manganese oxides. The results showed that MnOx@ACF had a strong adsorption ability and successfully activated PMS to degrade tetracycline hydrochloride (TCH), with a removal efficiency of 89.0% in 30 min. Influencing factors such as pH and coexisting ion species were investigated, and a five-cycle test was conducted. Singlet oxygen (1O2) was predominated in the MnOx@ACF/PMS system. A possible explanatory pathway of TCH was proposed based on the results of the high performance liquid chromatography-mass spectrometry. It was concluded that this study provides a novel insight into the activation of PMS for the degradation of organic matter by carbon-loaded multivalent manganese oxides.