逐步碳化水热炭材料非自由基催化氧化去除水中对乙酰氨基酚的作用机制

Nonradical Catalytic Oxidation Mechanism of Pyro-Hydrothermalchar for Acetaminophen Removal in Water

文中合成了一类以松木为原料的逐步碳化水热炭(PHTC)材料,并将其作为活化过氧单硫酸盐(PMS)的催化剂,用于水中对乙酰氨基酚(AP)的去除。材料性能筛选结果表明,经前期水热处理并900℃下热解5 h得到的材料PHTC900-5具备比表面积大(417 m2/g)、石墨化程度和结构缺陷程度高的特点。该材料与PMS组成的体系PHTC900-5/PMS经过60 min,可实现水相AP几乎完全去除,显示出对AP良好的催化降解去除性能,显著优于传统的水热炭(HTC)、生物炭(BC)以及较短热解时长制备的PHTC。有关催化机理的研究发现:PHTC900-5/PMS体系对AP的降解是以单线态氧非自由基途径为主导的催化氧化过程;同时,PHTC900-5/PMS体系适用于较宽的pH值(3~9),几乎不受常见共存无机阴离子的影响,腐植酸(HA)对反应略有抑制作用。研究表明,所制备的PHTC材料通过非自由基催化作用机制,可实现高效去除水中存在的典型药物污染物AP,可为实际水环境中药物类微污染的治理修复提供新的技术支持。

Pyro-hydrothermalchar(PHTC)materials from pinewood biomass was synthesized,and applied as catalysts of peroxymonosulfate(PMS)for the removal of acetaminophen(AP)in water.The screening results of materials performance indicated that PHTC900-5 obtained by preliminary hydrothermal treatment and pyrolysis at 900℃for 5 hours presented large specific surface areas(417 m2/g),high degree of graphitization and structural defects.The PHTC900-5/PMS system could achieve almost complete removal of AP in 60 min,and showed good catalytic degradation removal performance of AP,which suggested that PHTC900-5 was significantly better than traditional hydrothermal char(HTC),biochar(BC),and PHTC obtained with shorter pyrolysis time.The catalytic mechanism suggested that the degradation of AP by PHTC900-5 system was a catalytic oxidation process dominated by singlet oxygen nonradical pathway.In addition,the PHTC900-5/PMS system was suitable for a wide pH value range(3~9),hardly affected by inorganic anions,and slightly inhibited by humic acid(HA).This work demonstrates that PHTC materials prepared have potential removal capacity of AP in water through a nonradical catalysis mechanism,and provides new technical supports for remediation of drug micro-pollution in the actual water environment.