真菌电化学修复除草剂污染土壤:降解动力学探索

Fungal Electrochemical Remediation of Herbicide-contaminated Soil:Preliminary Study on Degradation Kinetics

【目的】微生物燃料电池(microbial fuel cell,MFC)在去除污染物的同时产出电能,是一种颇有前景的生态修复手段。构建真菌强化MFC装置,比较电动力(EK)、真菌、MFC修复除草剂污染土壤效果及优缺点,探索MFC在有机污染物修复中的应用潜力。【方法】设计了一种添加真菌进行生物强化的MFC,并用EK、真菌、MFC三种方法修复两种除草剂污染的灭菌土壤。经筛选和驯化的疣孢漆斑菌和踝节菌菌株用于后两种方法,研究真菌强化对MFC去除除草剂的影响。测量土壤pH、电导率、除草剂去除率,MFC产电性能,用气相色谱-质谱鉴定两种除草剂的降解产物。【结果】EK修复中,添加模拟电解液、碳纤维条、加电10 V的处理组7 d后氯氟吡啶酯(F)和高效氟吡甲禾灵(H)去除率分别为71%和38%。真菌、MFC处理F的最大去除率达到100%。对比踝节菌,疣孢漆斑菌对两种除草剂的降解性能更好,疣孢漆斑菌、踝节菌单菌构建的MFC对H的去除率分别为62.5%和24.1%。F降解产物为氟氯吡啶酸,H降解产物为乙酸大茴香酯,推测了降解路径和降解动力学。三种方法降解F以及EK降解H均符合动力学一级反应,而真菌和MFC降解H符合二级反应。【结论】对比EK、真菌修复,MFC修复效果更好,该方法可以较快地修复土壤又无需额外供电,是一种经济有效的自持式修复策略。

【Objective】Microbial fuel cell(MFC),which produces electricity while removing pollutants,is a promising means of ecological restoration.We aim to construct a fungal-augmented MFC device,compare the effects,advantages and disadvantages of electrokinetic(EK),fungal and MFC remediation against herbicides in the polluted soil,and explored the application potential of MFC in the remediation of organic pollutants.【Method】A novel MFC with fungal bioaugmentation was designed.The contaminated soil by two herbicides was remediated by three methods of EK,fungi and MFC remediations,and the screened and domesticated Talaromyces dalianensis and Myrothecium verrucaria strains were implemented in the latter two approaches.The effect of fungal augmentation on the removal of herbicides was studied.Soil pH,electrical conductivity,herbicide removal,and MFC electrical performance were quantified,and degradation products of two herbicides were identified by gas chromatography-mass spectrometry.【Result】In EK remediation,when simulated electrolyte,carbon fiber and 10 V were applied for 7 d,the removal rate of florpyrauxifen-benzyl(F)and haloxyfop-P(H)was 71%and 38%,respectively.Compared with H,F was more easily degraded,and fungal and MFC treatments completely removed it.Compared with T.dalianensis,M.verrucaria strain had better degradation capacity to both herbicides.MFC based on two fungi had the removal rate of 62.5%and 24.1%respectively toward H.The degradation product of F and H was halauxifen and 4-methoxybenzyl acetate,respectively,and the degradation pathways and kinetics were speculated.The degradation of F by three methods and the degradation of H by EK followed the first-order kinetic reaction,while the degradation of H by fungi and MFC followed the second-order reaction.【Conclusion】Compared with EK and fungal remediations,MFC remediation had a better effect,which can remediate the soil without the need for additional power supply,making it a cost-effective self-sustaining remediation strategy.