Activation of peroxymonosulfate (PMS) by rGO supported Co3O4 catalyst for iohexol degradation

Sulphate radical (SO 4 · - ) -based advanced oxidation process (SR-AOP) is a promising sewage treatment technology. Reduced graphene oxide (rGO) supported Co 3 O 4 composites were synthesized by a hydrothermal method for the degradation of iohexol (IOH) in the rGO/Co 3 O 4 /peroxymonosulfate (PMS) system. Experimental results show that rGO/Co 3 O 4 possessed much better PMS activated ability than pure GO or Co 3 O 4 , which is ascribed to the summation of rGO and Co 3 O 4 . The efficiency of rGO/Co 3 O 4 composite, single GO and Co 3 O 4 nanocrystals for the degradation of IOH were 98.7%, 15.8% and 79.8% at 15 min, and their corresponding reaction rate constants ( k app ) were 0.21 min −1 , 0.0077 min −1 and 0.080 min −1 , respectively. The results of active species capture experiment and electron paramagnetic resonance (EPR) experiment, showed that singlet oxygen is the main active species, which is non-radical degradation. rGO is conducive to the electron conduction of Co 3 O 4 , thus improving the efficiency of PMS activation. The system is simple and efficient, which is an effective technology to remove IOH.