Efficient Activation of Persulfate by TiO2/g-C3N4 Composite for Degradation of Acetaminophen Under Visible Light

The massive use of acetaminophen (APAP) poses a potential crisis for humans and the environment. In this paper, the degradation of APAP in aqueous solution was carried out using photocatalytic synergistic persulfate oxidation. To enhance the photocatalytic activity of g-C3N4 and thus activate the persulfate (K2S2O8, PS) more effectively, the heterojunction photocatalyst TiO2/g-C3N4 (TCN) was prepared by a hydrothermal method. The TCNPS catalytic system showed a high efficiency for APAP degradation. When the amount of TCN and PS added was 0.6 g/L, the degradation rate of APAP at 10 mg/L was 78.3% after 60 min of illumination. Moreover, the TCN-PS catalytic system was effective in removing organic pollutants in acidic, neutral, and weakly alkaline environments. The radical quenching experiment results indicate that both sulfate radicals (SO4-center dot) and hydroxyl radicals (similar to OH) are involved in the degradation reaction. After five cycles, the TCNPS catalytic system still has stable catalytic activity.