Enhanced activation of peroxymonosulfate by CNT-TiO2 under UV-light assistance for efficient degradation of organic pollutants

In this work, a UV-light assisted peroxymonosulfate (PMS) activation system was constructed with the composite catalyst of multi-walled carbon nanotubes (CNT) — titanium dioxide (TiO 2 ). Under the UV light irradiation, the photoinduced electrons generated from TiO 2 could be continuously transferred to CNT for the activation of PMS to improve the catalytic performance of organic pollutant degradation. Meanwhile, the separation of photoinduced electron-hole pairs could enhance the photocatalysis efficiency. The electron spin resonance spectroscopy (EPR) and quenching experiments confirmed the generation of sulfate radical (SO 4 • − ), hydroxyl radical (•OH) and singlet oxygen ( 1 O 2 ) in the UV/PMS/20%CNT-TiO 2 system. Almost 100% phenol degradation was observed within 20 min UV-light irradiation. The kinetic reaction rate constant of the UV/PMS/20%CNT-TiO 2 system (0.18 min −1 ) was 23.7 times higher than that of the PMS/Co 3 O 4 system (0.0076 min −1 ). This higher catalytic performance was ascribed to the introduction of photoinduced electrons, which could enhance the activation of PMS by the transfer of electrons in the UV/PMS/CNT-TiO 2 system.