Understanding oxygen-deficient La2CuO4-δ perovskite activated peroxymonosulfate for bisphenol A degradation: The role of localized electron within oxygen vacancy

An A(2)BO(4)-type oxygen-deficient perovskite (La2CuO4-delta, LCO), which owns a better low-temperature reducibility, more abundant oxygen vacancies (OVs) and surface oxygen species than the benchmark CuO oxide, was first applied in peroxymonosulfate (PMS) activation. At 0.7 g/L of LCO and 2 mM of PMS, more than 96 % of bisphenol A (BPA) was removed within 60 mM over a wide pH range of 3.1 - 9.1. The cycle of surface Cu(II)/Cu (I) redox couple and lattice oxygen (O2-)/O-2 were responsible for PMS activation. Besides, the OVs with localized electrons may directly activate PMS through single electron transfer pathway to generate surface-bound hydroxyl radical (center dot OH) and sulfate radical (SO4 center dot-), as well as less singlet oxygen (O-1(2)) for BPA degradation. The evolution of center dot OH, SO4 center dot and O-1(2) were revealed by EPR tests. Briefly, this study provides the mechanistic understanding of A(2)BO(4)-type perovskite in activation of PMS for water treatment.

Automated summary

An A(2)BO(4)-type oxygen-deficient perovskite (La2CuO4-delta, LCO) shows superior low-temperature reducibility and more abundant oxygen vacancies (OVs) compared to CuO oxide, and was successfully used in peroxymonosulfate (PMS) activation for more than 96% BPA removal within 60 mM over a wide pH range. The activation mechanism involves surface Cu(II)/Cu (I) redox couple, lattice oxygen (O2-)/O-2, and direct activation of PMS by OVs with localized electrons.