Construction of Magnetic Z-Scheme P-Doped BiOBr/CoFe2O4 Nanocomposite for Expeditious Visible Light Photocatalytic Palm Oil Mill Effluent Degradation via the Assistance of IO4- and S2O82-

P-BiOBr/CoFe2O4 nanocomposite was fabricated through a surfactant-free hydrothermal route and combined with electron acceptors (IO4- and S2O82-) for the first time to examine the palm oil mill effluent (POME) degradation and concurrently evaluated the biogas formation under visible light irradiation. The POME degradation efficiency reached 100% in 120 min over P-BiOBr/CoFe2O4/IO4-, which was much higher than the P-BiOBr/CoFe2O4/S2O82- (80.6%). Interestingly, the evaluation of the biogas production demonstrated that the P-BiOBr/CoFe2O4/IO4- photocatalysis generated greater amount of biogas (CH4 + CO2) compared to other systems. The great photocatalytic enhancement was due to the efficient charge carrier separation thanks to the Z-scheme heterojunction between P-BiOBr and CoFe2O4, and the electron trapping by IO4-. The hydroxyl radicals and photogenerated holes contributed majorly to POME degradation. Ultimately, the P-BiOBr/CoFe2O4 with IO4- and S2O82- assisting under visible light provided an effective and feasible method to degrade POME.