生物炭活化过硫酸钠的机理及降解土壤中多氯联苯的研究

In situ chemical oxidation (ISCO) based on persulfate for the remediation of contaminated groundwater and soils have received considerable attention in recent years. Developing the highly efficient and environmentally friendly methods to activate persulfate is becoming more and more important in the persulfate-based oxidation, which is beneficial for devising effective and economically feasible remediation strategies. Therefore, the persulfate activation by biochar for PCBs degradation was investigated in the present study, and the following questions will be addressed. Firstly, to elucidate the mechanism of persistent free radicals (PFRs) formation, the effects of pyrolysis temperature, metal content, surface functional group and the source of biochar on PFRs concentration and type in biochar were examined by EPR technique; Secondly, persulfate activation by biochar for the degradation of PCB28, a model contaminant, was studied. EPR technique was used to determine the relationships between free radical conversion (PFRs, sulfate and hydroxyl radicals) and PCB28 degradation, SPS decomposition, to elucidate the mechanism of persulfate activation. Finally, biochar/SPS system was used to degrade PCBs in soils, and the factors for controlling the remediation efficiency were examined in these experiments. The results of this study will provide a new pathway for biochar implication and for persulfate activation, and an effective strategy for the remediation of PCBs contaminated soil.

近年来基于过硫酸钠（SPS）的原位化学氧化技术已被广泛地应用与土壤与地下水的修复，筛选高效、环境友好的活化SPS技术在环境修复中越来越受到重视，并成为新的研究热点。基于此，本项目拟开展生物炭活化SPS降解污染土壤中多氯联苯（PCBs）的研究。利用电子顺磁共振技术（EPR）对生物炭中的持久性自由基（PFRs）进行定性和定量分析，考察生物炭来源、热解温度、金属含量和表面官能团等因素对PFRs种类和浓度的影响，阐明生物炭中PFRs的形成机制；以PCB28为实验对象，分析自由基浓度变化与PCB28降解及SPS分解的关系，结合自由基淬灭反应，从自由基水平上揭示生物炭活化SPS降解PCBs的作用机制；将生物炭/SPS体系应用于PCBs污染土壤的修复，考察影响修复效果的各项因素。以期发展一种新的生物炭的利用技术和过硫酸盐的活化方法，用于PCBs等污染场地的土壤修复。

近年来，基于过硫酸钠（SPS）的原位化学氧化技术已被广泛地应用与土壤与地下水的修复，筛选高效、环境友好的活化SPS技术在环境修复中越来越受到重视，并成为新的研究热点。基于此，本项目以生物炭为研究对象，考察其活化SPS降解土壤中多氯联苯（PCBs）的作用机制研究。利用电子顺磁共振技术（EPR）实现了对生物炭中的持久性自由基（PFRs）定性和定量表征，揭示了PFRs的形成机制；以PCB28为实验对象，分析了自由基浓度变化与PCB28降解及SPS分解的关系，结合自由基淬灭反应，从自由基水平上揭示了生物炭活化SPS降解PCBs的作用机制；将生物炭/SPS体系应用于实际土壤，阐明了SPS在土壤中的分解及自由基的产生过程，并解析了这一过程中的控制因子。以上的研究发展一种新的过硫酸盐的活化方式用于修复有机污染土壤，也为生物炭在环境领域的研究提供了一种新的思路。