The Study Of The Photocatalytic Degradation Mechanism Of Bisphenol A And Sulpiride By Ultrathin S-doped Graphitic Carbon Nitride Nanosheets

The wide use and distribution of pharmaceuticals and personal care products（PPCPs）and endocrine disrupting compounds（EDCs）had caused potential threats to the water environment and human health.In this study,ultrathin S-doped graphitic carbon nitride nanosheets（US–CN）was successfully synthesized and characterized,and its photodegradation of bisphenol A（BPA）and sulpiride（SP）were evaluated.Subsequently,the possible photocatalytic mechanism of the US-CN/visible light（VL）system was proposed.To further promote the degradation of SP,SP removal efficiency was evaluated under various conditions via the visible-light-assisted peroxydisulfate（PDS）activation method.The degradation pathways and mechanism were also discussed through quenching experiments,density functional theory（DFT）calculations,and intermediate products detection.Finally,the potential toxicity of SP and the degraded intermediate products from its degradation were predicted by Quantitative structure-activity relationship（QSAR）analysis.Our research found that:（1）After sulfur doping and ultrasonic treatment,US-CN possessed an ultra-thin（2.10-4.09 nm）and porous structure compare with graphitic carbon nitride（CN）,which facilitated photocurrent generation.（2）The results of photocatalytic degradation experiments showed that US-CN had a good photocatalytic degradation effect on BPA（removal rate reached 66.39%）,while the removal rate of SP was only22.13%.After combining with PDS,US-CN could effectively photodegrade SP（removal rate reached 90.55%）,and US-CN showed excellent stability in degradation.In addition,the singlet oxygen（¹O₂）generated by the US-CN/PDS/VL system played a significant role in SP degradation.（3）Based on the bonds of electron-rich atoms（9 N,12 N,21 N,22 O,and 23 O atoms）fracturing and the process and mechanism of SO₂ extrusion,the SP degradation pathway was proposed.Subsequently,three potentially toxic intermediates were predicted by QSAR analysis.This paper provided a theoretical basis for the economical and harmless degradation of PPCPs/EDCs in the water environment.