Z-Scheme TiO2/g-C3N4 Activation of Peroxymonosulfate to Remove Organic Pollutants: Properties and Mechanism

TiO2/g-C3N4 hybrids (TCNs) were constructed by an ammonium salt-assisted hydrothermal-high temperature calcination method and used to activate peroxymonosulfate (PMS) to degrade multiple simulated pollutants. The Z-scheme heterojunction between TiO2 and g-C3N4 can effectively promote the separation of electron-hole pairs and improve the photocatalytic activation effect of TCN. The degradation efficiency of RhB in the TCN1/PMS system was 92.3 %, which was only 59.8% and 63.2% in g-C3N4 /PMS the g-C3N4/PMS system and TiO2/PMS system, respectively, after 60 min of reaction under sunlight. The TCN1-4 sample prepared by adding (NH4)(2)SO4 into the precursor of TCN1 has a higher specific surface area (116.44 m(2)/g), which provides a better photocatalytic activation effect on PMS: the degradation efficiency of RhB in the TCN1-4/PMS system can reach 93.9% after 30 min, which was similar to that of the TCN1/PMS system after 60 min (92.3 %), and the reaction efficiency was doubled. Radical quenching experiments showed that free radicals ((OH)-O-center dot, SO4 center dot- , O-center dot(2)-), nonradicals (O-1(2)) and h(+) existed in the TCN1-4/PMS reaction system.