Highly-efficient degradation of triclosan attributed to peroxymonosulfate activation by heterogeneous catalyst g-C3N4/MnFe2O4

The g-C3N4/MnFe2O4 as recyclable catalyst was synthesized via auto-combustion sol-gel method. Peroxymonosulfate (PMS) activation by the catalyst for triclosan (TCS) degradation was investigated considering the activation performance, reaction parameters and activation mechanism. The catalyst prepared with 1:1 of g-C3N4 and MnFe2O4 molar ratio performed the best catalytic activity in the TCS degradation and with lest metal leaching. The concentration of Cl- showed a dual effect on the TCS degradation, while HCO3- and SO42- performed inhibitory effect. Sulfate radicals, hydroxyl radicals, superoxide and non-radical single oxygen contributed to the degradation of TCS. Compared with MnFe2O4/PMS system, few heavy metals were leached from g-C3N4/MnFe2O4(1:1)-PMS after each reuse (Fig. S6b), suggesting that g-C3N4 was conducive to the stability of g-C3N4/MnFe2O4(1:1) catalyst. Dichlorination, hydroxylation, cyclization and other bond breaking reaction were inferred as the TCS degradation pathways. These results demonstrated that g-C3N4/MnFe2O4(1:1) was a highly effective and stable catalyst for PMS activation to treat toxic organic pollutants in water.