Heterogeneous activation of peroxymonosulfate by hierarchical CuBi 2 O 4 to generate reactive oxygen species for refractory organic compounds degradation: morphology and surface chemistry derived reaction and its mechanism

Abstract

Activation of peroxymonosulfate (PMS) by a novel hierarchical CuBi₂O₄ generated reactive oxygen radical for degradation refractory organic compounds in aqueous solution, which would be controlled by the morphology and surface chemistry of solid catalyst. It's found that the activation ability of CuBi₂O₄ toward PMS was highly dependent on the morphology and surface hydroxyl group, as using rhodamine B (RhB) as the model compound. The spherical CuBi₂O₄, which possessed higher density of surface hydroxyl group, exhibited better catalytic activity in RhB degradation than scattered cluster CuBi₂O₄, and as-prepared CuBi₂O₄ could efficiently activated PMS to degrade RhB within a wide pH range as an absolute heterogeneous process. The emerging organic chemicals, including bisphenol A, 1H-benzotriazole, and carbamazepine, could also be effectively removed in this novel CuBi₂O₄/PMS. Furthermore, activation mechanism of PMS by as-prepared CuBi₂O₄ was proposed, the existence of surface hydroxyl group bonded with Cu(II), and inward electron transfer cycling reaction between Cu(II)/Cu(I) facilitated the effective activation of PMS to generate SO₄^·− and ·OH. In addition, the intermediates of RhB formed in this process were identified by silylation derivatation-GC-MS and LC-high-resolution MS/MS, and degradation pathway was proposed.