Aluminum-based layered metal oxides activating peroxymonosulfate for bisphenol A degradation via surface-bound sulfate radicals and singlet oxygen

In this study, a series of aluminum-based layered metal oxide with various divalent metals (M2+Al-LMOs) were prepared and employed in activation of peroxymonosulfate (PMS) for bisphenol A (BPA) degradation. The BPA removal rates of M2+Al-LMOs were ordered as: CoAl(100%) > MnAl(75.6%) > CuAl(63.2%) > NiAl(9.0%) > MgAl = ZnAl-LMO(0%). CoAl-LMO showed the highest kinetic constant (k = 1.329 µmol-1gcat-1s-1), which was 3.95 times of MnAl-LMO, 5.36 times of CuAl-LMO, 88.6 times of NiAl-LMO and 443 times of MgAl-LMO and ZnAl-LMO, respectively, and also exhibited the highest TOC removal rate (83.3%). The surface-bound sulfate radical (SO4·-) and singlet oxygen (1O2) were elucidated as the dominant reactive oxygen species (ROS) for BPA degradation. The M2+Al-LMOs/PMS system not only displayed wide applicability in different pH and inorganic anions environments, but also had excellent stability and reusability. This work provides a novel family of M2+Al-LMOs to activate PMS for water treatment.