氧含量和Fe(Ⅲ)对生物炭降解对硝基苯酚的影响机制  

Effect mechanism of oxygen content and Fe(Ⅲ)on biochar degradation on P-nitrophenol

作　　者：苟全 李靖 陈芳媛 李杉 赵泽颖 段文焱 GOU Quan;LI Jing;CHEN Fangyuan;LI Shan;ZHAO Zeying;DUAN Wenyan(Faculty of Environmental Science and Engineering,Yunnan Provincial Key Lab of Carbon Sequestration and Pollution Control in Soil,Kunming University of Science and Technology,Kunming,650500,China)

机构地区：[1]昆明理工大学环境科学与工程学院,云南省土壤固碳与污染控制重点实验室,昆明650500

出　　处：《环境化学》2024年第7期2444-2453,共10页Environmental Chemistry

基　　金：国家自然科学基金(41807377,41961134002);昆明理工大学高层次人才平台建设项目(KKK201722018);云南省重大科技项目(CB22197S011A)资助.

摘　　要：生物炭因其丰富的比表面积和独特的理化性质在污染物治理方面具有广泛的应用潜力,但其降解污染物过程受环境因素影响的机制尚不清楚.本文以松木木屑为原料制备松木生物炭(BC500),探讨了氧气和Fe(Ⅲ)离子对BC500降解有毒有机农药对硝基苯酚(PNP)的影响.结果表明,在酸性有氧条件下,BC500对PNP的降解量是无氧条件的1.35倍,这表明除了自身直接降解作用外,生物炭还能通过氧气介导生成活性氧自由基间接降解PNP.此外,通过XPS、AAS和FTIR等表征显示,在有氧条件下,不同浓度的Fe(Ⅲ)离子(2.8—280 mg·L^(-1))对BC500降解PNP均起抑制作用.这是由于Fe(Ⅲ)离子在环境pH较低时具有较强的氧化能力,通过竞争BC500传递给氧气的电子导致超氧阴离子(·O_(2)^(-))生成途径被屏蔽.而在无氧条件下加入Fe(Ⅲ)则促进了PNP降解,从0.68 mg·g^(-1) BC增加到1.79 mg·g^(-1) BC,因为Fe(Ⅲ)能增强BC500对PNP的吸附,并进一步促进其直接降解作用.结果表明,BC500施用于酸性含铁废水中时,无氧环境更利于PNP的降解,而有氧环境下Fe(Ⅲ)会抑制PNP的降解.本研究为生物炭应用于酸性含铁废水环境中的有机污染物治理提供了理论依据.Biochar has wide application potential in pollutant control due to its rich specific surface area and unique physicochemical properties,but the mechanism of its degradation process affected by environmental factors is unclear.In this paper,pine biochar(BC500)was prepared from pine wood chips,and the effects of oxygen and Fe(Ⅲ)ions on BC500’s degradation of toxic organic pesticides and nitrophenol(PNP)were discussed.The results showed that under acidic aerobic conditions,the degradation of PNP by BC500 was 1.35 times that of anaerobic conditions,which indicated that in addition to its own direct degradation,biochar could also indirectly degrade PNP through oxygen-mediated formation of reactive oxygen radicals.In addition,characterization by XPS,AAS and FTIR showed that under aerobic conditions,Fe(Ⅲ)ions at different concentrations(2.8—280 mg·L^(-1))inhibited the degradation of PNP by BC500.This is due to the strong oxidation capacity of Fe(Ⅲ)ions at low ambient pH,and the electrons transferred to oxygen by competing BC500 cause the superoxide anion(·O_(2)^(-))production pathway to be shielded.The addition of Fe(Ⅲ)under oxygen-free conditions promoted PNP degradation,from 0.68 mg·g^(-1) BC to 1.79 mg·g^(-1) BC,because Fe(Ⅲ)could enhance the adsorption of PNP by BC500 and further promote its direct degradation.The results showed that when BC500 was applied to acidic iron-containing wastewater,the anaerobic environment was more conducive to the degradation of PNP,while Fe(Ⅲ)inhibited the degradation of PNP in the aerobic environment.This study provides a theoretical basis for the application of biochar to the treatment of organic pollutants in acidic iron-containing wastewater environment.

关 键 词：对硝基苯酚 氧化还原降解 木屑生物炭 酸性废水 

分 类 号：X-1[环境科学与工程] O6[理学—化学]