Zn-Mn bimetallic oxide derived from waste batteries to activate peroxymonosulfate for bisphenol A removal under visible light irradiation

In this study, Zn-Mn bimetallic oxides (ZMBO) were synthesized from spent alkaline zinc-manganese batteries to effectively activate peroxymonosulfate (PMS) under visible light irradiation. PMS activation can be triggered by Mn-composition, which could be augmented thanks to the visible light response of Zn-composition. Meanwhile, the introduction of PMS could effectively hinder the rapid recombination of photogenerated electron-hole pairs. By adding 1.00 mM of PMS and 0.50 g/L of Zn-Mn bimetallic oxides (ZMBO), the Vis/ZMBO/PMS system could remove 90.0% of bisphenol A in 120 min under the neutral pH condition. Quenching experiments and electron paramagnetic resonance technique were used to identify the reactive species, and the singlet oxygen as well as photogenerated holes were identified as the major reactive species which exhibited high selectivity towards electron-rich contaminants. X-ray photoelectron spectroscopy (XPS) confirmed that the cycles between manganese in Mn(II), Mn(III) and Mn(IV) promoted PMS activation. The ZMBO photocatalyst exhibited excellent reusability. The existence of common anions (Cl–, NO–3 and SO2–4) presented the slight inhibition for BPA degradation while little BPA was removed with the addition of 5.00 mM H2PO–4. This study provides an alternative for the feasible utilization of waste battery, and the Vis/ZMBO/PMS system shows great potential in the elimination of pollutant with electron-donating capability from water.