生物炭基材料活化过一硫酸盐降解有机污染物的研究进展

Review of Biochar-Based Materials for Catalyzing Peroxymonosulfate Degradation of Organic Pollutants

水体中难降解有机物对人体和生态环境存在潜在威胁,开发高效、环保和低成本的催化体系对修复此类废水具有重要意义.生物炭基材料-过硫酸盐高级氧化体系在污水处理领域有广阔的应用前景,为了进一步明确生物炭基材料活化PMS(过一硫酸盐)降解有机污染物的性能及微观机制,综述了生物炭、(非)金属元素掺杂生物炭和金属氧化物-生物炭复合材料3种典型生物炭基材料活化PMS降解有机污染物的催化活性及界面反应机制.结果表明:生物炭基材料表面催化位点(如含氧官能团、缺陷、持久性自由基、金属原子等)可通过自由基或非自由基方式促进PMS活化,进而促进SO_(4)^(-)·(硫酸根自由基)、·OH(羟基自由基)和O_(2)^(-)·(超氧自由基)等活性物种的产生,最终增加相应体系的催化活性;使用(非)金属元素掺杂或者负载金属(氧化物)能够显著改变生物炭电荷分布和活性位点,进而增加生物炭基材料的催化活性.但目前的研究仍存在一些不足,如多种活性位点在生物炭基材料活化PMS过程中的协同作用机制尚不明确,杂原子共掺杂生物炭或生物炭负载单原子催化剂在PMS体系中的催化活性及机制、自由基非自由基方式的协同作用机制也兹待研究.此外,污染物自身结构特性对生物炭基材料催化活性的影响机制也有待进一步探讨.

The non-biodegradable organic pollutants in the water environment pose a potential threat to human body and ecological environment.Thus,it is very important to develop efficient,environmental and low-cost catalytic systems to remove these contaminants.Biochar-based materials and PMS(peroxymonosulfate)systems,as advanced oxidation technologies,have potential applications in wastewater treatment.In order to clarify the properties and interfacial mechanisms of biochar and PMS to degrade organic pollutants,the catalytic activities and mechanisms of three typical biochar-based materials,including biochar,non-metal doped biochar and metal oxide-biochar are reviewed.The results show that the surface catalytic sites on biochar-based materials(such as oxygen-containing groups,defects,PFRs(persistent free radicals)and metal atoms)can oxidize PMS through radical or non-radical pathways.In this progress,the SO_(4)^(-)·(sulfate radical),·OH(hydroxyl radical)and O_(2)^(-)·(superoxide radical)radicals are produced to promote the catalytic activity of the corresponding systems.Besides,non-metal doped biochar and metal oxide-biochar also have higher catalytic activities than pristine biochar due to the significantly difference in electric charge distributions and active sites.However,there are still some deficiencies in the present studies.For example,the synergistic mechanisms of various active sites in the activation of PMS by biochar-based materials are still unclear,the catalytic activity and mechanism of heteroatomic co-doped biochar or biochar-supported monatomic catalyst in the PMS systems need to be further studied,the synergistic mechanism of free radicals and non-free radical activation is unclear,and the influence of pollutant structure on the catalytic activity of biochar-based materials needs to be further explored.