氧化剂类型对rGO/CNTs催化膜去除水中消炎药成分的影响

Effects of peroxide types on the removal of anti-inflammatory medicines in water with rGO/CNTs catalytic membranes

磺胺吡啶(SSZ)与甲氧苄啶(TMP)是常用的消炎药组合,其排入水体后可能引发生态风险。为实现污染物的高效净化,将还原氧化石墨烯和碳纳米管(rGO/CNTs)复合碳层负载于微滤膜表面,并通过活化多种氧化剂,建立了可实现连续处理的原位催化氧化体系。研究结果表明,过二硫酸盐(PDS)和过一硫酸盐(PMS)分别是rGO/CNTs催化膜去除水中SSZ和TMP的最佳氧化剂,而过氧化氢(H_(2)O_(2))体系的除污效能随运行时间衰减较快。由活性氧组分淬灭实验、碳层表面基团表征和密度泛函理论计算可知,碳层缺陷结构是吸附、活化PDS和PMS分子,诱发表面氧化和单线态氧(^(1)O_(2))等非自由基氧化的关键位点。与羟自由基(·OH)反应占主导的H2O2体系相比,PDS和PMS催化氧化具有明显的目标物选择性,能够更有效地抵抗水体背景物质的干扰和减缓膜污染的形成。上述发现对于进一步优化碳质催化膜的功能设计、推动原位催化氧化新技术发展具有指导意义。

Sulfapyridine(SSZ)and trimethoprim(TMP)were the typical combinations of antiinflammatory medicines,and it would cause ecological risks when discharged into water bodies.The carbon mats composited with reduced graphene oxide and carbon nanotubes(rGO/CNTs)were loaded onto the microfiltration membranes,which were used to activate various peroxides for the removal of pollutants.Thus,an in-situ catalytic oxidation system could be built up in the continuous flow mode.Results showed that peroxodisulfate(PDS)and permonosulfate(PMS)were the best alternative for effectively removing SSZ and TMP with rGO/CNTs catalytic membranes,respectively.Meanwhile,the performances of hydrogen peroxide(H_(2)O_(2))-based systems significantly decreased as increasing continuous operation time.According to the quenching experiments of reactive oxygen species,functional group characterization on the surface of carbon mats and density functional theory calculations,the defects structures in carbon mats were considered as the critical sites for the adsorption and activation of PDS and PMS molecules,resulting in non-radical pathways including surface-confined oxidation and singlet oxygen(^(1)O_(2)).In comparison to H_(2)O_(2)-based systems dominated by hydroxyl radical(·OH)reaction,the PDS and PMS catalytic oxidation processes exhibited more significantly target selectivity,more resistant to background substances in real water matrices and more effectively control membrane fouling.These findings could provide the guides in the further optimizing functional design of carbonaceous catalytic membranes and promoting the development of novel in-situ catalytic oxidation processes.