A novel three-dimensional spherical CuBi2O4 nanocolumn arrays with persulfate and peroxymonosulfate activation functionalities for 1H- benzotriazole removal

A novel CuBi2O4 consisting of self-assembled spherical nanocolumn arrays (CuB-H) was synthesized via a facile hydrothermal method. It was further modified by controlling the Cu:Bi ratio during synthesis to become an efficient bi-functional catalyst (CuB-2.5) activate persulfate (PS) and peroxymonosulfate (PMS) for 1H-benzotriazole (BTZ) removal. Characterization of CuB-2.5 using XRD, 10 FESEM, FTIR, BET and XPS revealed that it was morphologically similar to CuB-H and the molecular formula, as determined from the XRD results, was Cu1.2Bi1.6O3.6 with 2.4% w/w of CuO. The CuB-2.5 catalyst exhibited superior performance for BTZ removal via PS and PMS activations over the Cu (aq), CuO, CuBi2O4 (CuB-M, microsphere) and CuB-H. The performance of CuB-2.5 was investigated at different initial PS/PMS dosages, initial catalyst loadings and initial BTZ concentrations. Interestingly, it 15 was found that the interand intra-molecular hydrogen bonding plays a prominent role in the BTZ removal mechanism in both the PS and PMS systems. Meanwhile, PMS is relatively easier to be activated leading to a faster BTZ removal rate over the PS system. The intermediate products of BTZ degradation produced from the PS and PMS systems were similar indicating the similar degradation pathway. The catalyst could still retain its morphology and can be reused multiple times. 20