摘要
我国由于工农业快速发展、农药化肥大量使用等原因形成大量重度有机污染场地,环境风险极高,迫切需要发展高效、快速的有机污染土壤修复技术.本研究提出流化床介质阻挡放电(DBD)等离子体耦合CeO_(2)/γ-Al_(2)O_(3)催化修复阿特拉津(ATZ)污染土壤的方法.同时,表征分析了催化剂的物化性能,考察了气体流速和活性组分负载量对ATZ降解效果的影响,最后揭示了流化床DBD等离子体耦合催化作用机理.结果表明,15%CeO_(2)/γ-Al_(2)O_(3)催化剂具有最高含量的Ce^(3+)和表面吸附氧(Oads),能够提供丰富的氧空位.等离子体耦合催化系统在充分流化状态下显示出优越的降解性能,尤其在气体流速为1.0 m·s^(-1)和活性组分负载量为15%的实验条件下,流化床DBD等离子体耦合催化系统中ATZ降解效率(85.4%)和能量效率(0.149 mg·kJ^(-1))经过12 min放电处理后均达到最优值,比流化床DBD等离子体系统分别提升了21.4%和22.1%.放电产生的高能电子及其轰击背景气体产生的化学活性物质与ATZ分子发生碰撞反应.耦合催化之后Ce^(4+)和Ce^(3+)之间的氧化还原循环促进氧空位的形成,吸附并分解O_(3)和O_(2)为其它活性氧物质.以上活性物质共同攻击ATZ分子及中间产物的侧链C—N键和C—Cl键等,使其最终矿化为CO_(2)和H_(2)O.基于产物鉴定结果及催化作用机理,提出了6条ATZ降解路径,其中,脱烷基化和脱氯-羟基化为主要路径.最后,毒性评价结果表明流化床DBD等离子体耦合催化系统能够降低ATZ中间产物毒性,实现逐步脱毒.
Due to the rapid development of industry and agriculture,as well as the extensive use of pesticides and fertilizers,a large number of heavily organic contaminated sites have emerged in our country,posing significant harm to the environment.Consequently,there is an urgent need to develop efficient and rapid remediation technologies for organic-contaminated soil.In this study,a fluidized-bed dielectric barrier discharge(DBD)plasma coupled CeO_(2)/γ-Al_(2)O_(3)catalysis was proposed to remediate atrazine(ATZ)-contaminated soil.The physicochemical properties of catalysts were characterized and analyzed,and the effects of gas velocity and active component loading on the degradation of ATZ were investigated.Finally,the mechanism of fluidized-bed DBD plasma coupled catalysis was clarified.The results indicated that the 15%CeO_(2)/γ-Al_(2)O_(3)catalyst had the highest content of Ce^(3+)and surface adsorbed oxygen(Oads),which could provide abundant oxygen vacancies.And the plasma coupled catalysis system exhibited superior degradation performance in the fully fluidization.Especially under the experimental conditions of gas velocity of 1.0 m·s^(-1) and active component loading of 15%,the ATZ degradation efficiency(85.4%)and energy efficiency(0.149 mg·kJ^(-1))in the fluidized-bed DBD plasma coupled catalysis system reached the optimal values after 12 min plasma discharge treatment,which were 21.4%and 22.1%higher than those in the fluidized-bed DBD plasma system,respectively.The high-energy electrons generated by the discharge and the chemical active species produced by the bombardment of the background gas interacted with the ATZ molecules.The coupling catalysis promoted a redox cycle between Ce^(4+)and Ce^(3+),facilitating the formation of oxygen vacancies that adsorbed and decomposed O_(3)and O_(2)into other active oxygen species.These chemical active species collectively attacked the C-N and C-Cl bonds on the side chains of ATZ molecules and intermediates,which gradually decomposed into small molecules,and eventually
作者
瞿莹
郭凤艳
崔宇韬
谭玉玲
朱金伟
李杰
姜楠
QU Ying;GUO Fengyan;CUI Yutao;TAN Yuling;ZHU Jinwei;LI Jie;JIANG Nan(Chinese Research Academy of Environmental Sciences,Beijing 100012;School of Environmental Science and Technology,Dalian University of Technology,Dalian 116024;School of Electronic Information and Electrical Engineering,Dalian University of Technology,Dalian 116024)
出处
《环境科学学报》
CAS
CSCD
北大核心
2024年第1期400-413,共14页
Acta Scientiae Circumstantiae
基金
国家自然科学基金(No.52177130)
中央高校基本科研业务费专项资金(No.DUT20ZD202)
国家重点研发计划(No.2022YFC3703403)。
关键词
流化床等离子体
介质阻挡放电
等离子体催化
土壤修复
毒性评价
fluidized-bed plasma
dielectric barrier discharge
plasma catalysis
soil remediation
toxicity evaluation
