多环芳烃-重金属复合污染土壤威胁着生态安全和人体健康，因而寻求经济、有效和绿色的修复技术具有重要的理论和现实意义。针对微生物强化修复中注入菌在土壤中的活性较低和复合污染土壤修复机制仍不明确等问题，本项目拟以土壤中芘和镉为目标污染物，制备核-壳结构的硅凝胶固定化菌剂，使芘降解菌在核内保持较高活性且可利用芘生长繁殖，同时硅壳吸附芘和稳定镉，达到高效去除芘和有效稳定镉的双重目的。以“固定化菌剂-芘/镉-土壤”体系为研究主线，在明确菌剂特征和性能的基础上，深入研究芘/镉和载体对菌株活力的影响，理清“固定化菌剂-芘/镉”之间的相互作用规律和微观界面特征；探讨菌株和芘/镉在土壤颗粒与固定化基质间的分配和迁移转化规律，综合分析并揭示硅凝胶固定化菌剂去除土壤中芘和稳定镉的同步作用机制，为开发绿色有效的生物活性材料用于实地复合污染土壤的修复提供新思路和科学依据。

Ecological security and human health have been threatened by PAH-metal co-contamination in soil. Therefore, to seek an economic, effective and green bioremediation technology has a good theoretical and practical significance. Based on the low activity of inoculant bacteria in soil during bioaugmentation and still unclear mechanism on remediation of co-contamination soil, in this project, pyrene and Cd in soil will be studied and pyrene-degrading bacteria will be immobilized in the core-shell ORMOSIL gel for efficient removal of PAHs and simultaneous stabilization of heavy metal in co-contaminated soil. The silica shell will adsorb pyrene and Cd, meanwhile, bacteria growth and proliferation by using pyrene will occur in the core. Interactions among the immobilized bacteria, pyrene/Cd and soil are the leading clue. Details are listed as follows: (1) investigating the characteristics, vitality and performances of this immobilized bacteria; and on this basis, (2) systematically studying interactions and interface microstructural characteristics of the immobilized matrix, bacteria and pyrene/Cd, then verifying influences of the matrix and pyrene/Cd on bacteria; (3) exploring the distribution and transfer features of pyrene/Cd and bacteria between soil particles and the immobilization matrix, then further revealing the synchronization mechanism of PAHs degradation and heavy metal stabilization in co-contaminated soil by immobilized bacteria in core-shell silica gel, based on the comprehensive analysis. The finding of this project will provide a new thought and scientific support to exploit green and effective bioactive materials for bioremediation of co-contamination site.