光催化已被证明是处理抗生素废水的一项优秀技术,但是参与该过程的每种活性物种对抗生素降解的影响尚不清楚。因此,以三聚氰胺和Ti3C2为前驱体,采用机械搅拌和超声辅助的一步煅烧方法,成功合成了S-方案异质结光催化剂Ti3C2/g-C3N4/TiO2。通过多重表征和功函数计算,详细研究了其形成机理。异质结光催化剂不仅使其能够保留具有强氧化和还原能力的活性物种,而且大大促进了光生载流子的分离和转移,在120分钟内对四环素(TC)表现出94.19%的优异降解效率。重要的是,优先攻击站点,降解途径,降解中间体及其在每个单一活性物种(·O2-,h+,·OH)首先通过设计实验进行了积极的探索和评估,福井函数理论计算,HPLC-MS,大肠杆菌毒性实验,ECOSAR计划。结果表明,·O2-对TC的首选攻击位点为高f值的O20,C7,C11,O21和N25原子。·O2-产生的中间体的毒性也低于h和·OH产生的中间体。
Photocatalysis has been proven to be an excellent technology for treating antibiotic wastewater, but the impact of each active species involved in the process on antibiotic degradation is still unclear. Therefore, the S-scheme heterojunction photocatalyst Ti3C2/g-C3N4/TiO2 was successfully synthesized using melamine and Ti3C2 as precursors by a one-step calcination method using mechanical stirring and ultrasound assistance. Its formation mechanism was studied in detail through multiple characterizations and work function calculations. The heterojunction photocatalyst not only enabled it to retain active species with strong oxidation and reduction abilities, but also significantly promoted the separation and transfer of photo-generated carriers, exhibiting an excellent degradation efficiency of 94.19 % for tetracycline (TC) within 120 min. Importantly, the priority attack sites, degradation pathways, degradation intermediates and their ecological toxicity of TC under the action of each single active species (·O2-, h+, ·OH) were first positively explored and evaluated through design experiments, Fukui function theory calculations, HPLC-MS, Escherichia coli toxicity experiments, and ECOSAR program. The results indicated that the preferred attack sites of ·O2- on TC were O20, C7, C11, O21, and N25 atoms with high f+ value. The toxicity of intermediates produced by ·O2- was also lower than those produced by h+ and ·OH.