Efficient degradation of carbamazepine by sulfate doped LDO/CN in the photo-assisted peroxymonosulfate system

Abstract

Improving the utilization rate of active sites through rational design of material structure is considered to be an effective way to enhance the activation efficiency and degradation performance of peroxymonosulfate (PMS). Co-sulfate anions-induced layered double oxide/carbon nitride (Co-SLDO/CN) was prepared by sulfate anion induction for the rapid degradation of carbamazepine in the photo assisted persulfate system. Graphitic carbon nitride (CN) provided nucleation sites for Co-SLDH to inhibit its aggregation. Sulfate anions induced the material to transform into three-dimensional flower balls, promoting the formation of oxygen defects, which is beneficial for charge separation and thus promotes more electrons to participate in the catalytic reaction. The synergistic effect of visible light/PMS system and oxygen vacancies (Vo) enabled 100 % degradation efficiency of 10 mg/L carbamazepine (CBZ) to be achieved within 10 min. Among them, the electron transfer of Co (III)/Co (II) promoted the decomposition of PMS to generate SO4-•, visible light activated Co-SLDO/CN to produce eCB- and hVB+, and the O2 in the micro area around the oxygen vacancy captured electrons to generate O2•− and 1O2. Seventeen intermediates, such as 10, 11-dihydroxy-carbamazepine, and possible CBZ degradation pathways were proposed, and the overall toxicity was found reduced through experiments, which was consistent with eco-SAR software prediction. After four cycles, the degradation rate of CBZ remained at 100 %, and the system showed good efficiency while degrading various PPCPs, indicating practical application potential.