铁改性生物炭-凹凸棒石载体固定化菌剂制备及其对氯苯污染土壤修复作用OA北大核心CSTPCD

Chlorobenzene is an important intermediate and an organic solvent used in the organic chemical industry.In the process of production,transportation,and illegal emissions,chlorobenzene migrates into the soil,posing a serious threat to the ecological environment,even directly entering and endangering human health through the food chain.As a significant receiving environment for chlorobenzene,the pollution status and green efficient remediation of soil have always been a hot issue in the environmental field.Microbial remediation has attracted much attention in the field of environmental remediation owing to its advantages of low energy consumption,green production,and lack of secondary pollution.However,microbial remediation is often confronted with key technical problems in the practice of contaminated soil remediation,such as poor survival ability and low degradation efficiency of bacterial strains.Biochar can be used to immobilize microorganisms for efficient degradation;however,its performance is often limited by its specific surface area,functional groups,and other factors.In this study,iron sulfate,attapulgite,and reed straw were mixed at a ratio of 1꞉2꞉10 and then pyrolyzed at a high temperature of 500℃for 2 h without oxygen.Reed biochar was modified to improve its immobilization capacity for degrading microorganisms.Furthermore,the immobilization conditions of Pseudomonas aeruginosa W3 were optimized to prepare an iron-modified biochar-attapulgite carrier-immobilized bacterial agent(BFAT@W3)for the application in the remediation of contaminated soil.The results showed that,after the combined modification with the Fe2(SO4)3 and attapulgite,the specific surface area(210.7 m2·g-1)and pore volume(0.13 cm3·g-1)of BC-Fe-ATP were higher and the functional groups were more abundant.The optimal conditions for the immobilization of microorganisms were as follows:adsorption temperature of 37℃,the adsorption time of 16 h,and carrier dosage of 15 mg·mL-1.Under these conditions,the concentration of live cells immobilized on the carrier was 2.10×109·g-1.In practical soil contaminated by chlorobenzene,the removal rate of chlorobenzene was higher(83.4%),while the proportion of BFAT@W3 was 3꞉100,which was 18.6%higher than that of W3.High-throughput sequencing of 16S rRNA showed that the application of 3꞉100 BFAT@W3 effectively increased the relative abundance of Proteobacteria and Pseudomonas in the soil.Compared with the same proportion of W3,the application of 3꞉100 BFAT@W3 effectively increased the relative abundance of Proteobacteria and Pseudomonas in the soil by 41.3%and 36.7%,respectively,enhancing the competitive advantage in soil microbial communities.In this study,an iron-modified biochar-attapulgite carrier with good performance was used to immobilize efficient degrading bacterial agents,which provided technical support for the bioremediation of chlorobenzene-contaminated soil.