Advanced oxidation via the synergy of C-defective/ C–O band modified ultrathin porous g-C3N4 and PMS for efficient photothermal degradation of bisphenol pollutants and lignin derivatives

This work uses thermal polymerization of urea nitrate, oxyacetic acid and urea as the raw material to prepare ultra-thin porous carbon nitride with carbon defects and C–O band (OA-UN-CN). Density functional theory (DFT) calculations showed OA-UN-CN had narrower band gap, faster electron transport and a new internal construction electric field. Additionally, the prepared OA-UN-CN significantly enhanced photocatalytic activation of peroxymonosulfate (PMS) due to enhanced light absorption performance and faster electron overflow. As the result, the OA-UN-CN/PMS could entirely degrade bisphenol A (BPA) within 30 min, where the photodegradation rate was 81.8 and 7.9 times higher than that of g-C3N4 and OA-UN-CN, respectively. Beyond, the OA-UN-CN/PMS could likewise degrade other bisphenol pollutants and sodium lignosulfonate efficiently. We suggested possible photocatalytic degradation pathways accordingly and explored the toxicity of its degradation products. This work provides a new idea on the development of advanced photocatalytic oxidation processes for the treatment of bisphenol pollutants and lignin derivatives, via a metal-free photothermal-catalyst.