颗粒污泥自固定负载生物纳米钯强化有机物还原脱卤机制及调控方法

Nanopalladium is a good catalyst for hydrogenation reaction, which can reductively dehalogenate a variety of halogenated organic compounds. This applicant proposes a new strategy for nanopalldium formation,immobilization and application for degradation of halogenated organic comounds, in which biogenic nanopalladium (Bio-Pd) will in-situ formed and immobilzed in a natural biocarrier anaerobic granular sludge (AGS) and thus Pd-hosting AGS (Pd-AGS) will be established and used for reductively degradation of halogenated organic compounds. The Pd-AGS would possess bi-function of chemical catalysis and microbial degradation. The hydrogen donor required by the Pd catalyst in AGS can be supplied through synergistic metabolism of different microbial species. In this study, we will investigate the methods, conditions and key factors influencing Bio-Pd formation in the AGS, elucidate the possible relationships among Pd spatial distribution-Pd catalytic activity-microbial degradation ability of AGS and establish a controlling method for Bio-Pd reduction in AGS. Moreover, we will investigate the impacts of Bio-Pd immobilization on microbial metabolic function, activity and microbial community structure of AGS. Finally, the Pd-AGS will be used to reductively degrade some typical halogenated compounds. The degradation mechanisms, path and kinetics will be explored, the changes of Pd-AGS functions and methods for Pd replenish and regeneration after long-term application will be studied. This research has both theoretical value and practical value, which will facilitate the application of biogenic-nanopalladium and AGS technology in the degradation of recalcitrant organic pollutants.

纳米钯是一种优良的加氢反应催化剂，能够催化还原多种卤代有机污染物。本研究创新性地提出利用厌氧颗粒污泥原位合成生物纳米钯（Biogenic Nanopalladium），从而将纳米钯载入到生物载体-颗粒污泥中，构建具有钯化学催化-生物催化复合功能的载钯颗粒污泥，并利用颗粒污泥中微生物的协同代谢为纳米钯催化提供持续氢还原动力，强化其对卤代有机物的还原降解。主要研究内容包括：厌氧颗粒污泥自固定形成生物纳米钯方法、条件与关键因子，颗粒污泥纳米钯空间分布-催化性能-生物活性之间的内在关系，建立颗粒污泥钯定向还原调控方法；探讨生物纳米钯形成对颗粒污泥代谢活性、功能及微生物群落结构影响；研究载钯颗粒污泥对典型卤代污染物还原脱卤机制、途径及动力学，长期应用条件下其功能演变规律及生物纳米钯活性补充与再生方法。该研究对于提升生物纳米钯及厌氧颗粒污泥技术在难降解有机废水中的应用，具有重要的理论价值与实践意义。

本研究创新性地利用厌氧颗粒污泥(AGS)原位合成生物纳米钯（Bio-Pd），构建了具有钯化学催化-生物催化复合功能的载钯生物颗粒(Pd-AGS)，研究了Bio-Pd合成方法、条件与关键因子，建立了定向还原调控方法；探讨了Bio-Pd对颗粒污泥代谢活性、功能及微生物群落结构影响；研究了Pd-AGS对典型卤代污染物的还原脱卤效应、影响因素及机制。该研究对于拓展生物纳米技术及厌氧颗粒污泥技术在难降解有机废水中的应用，具有重要的理论价值与实践意义。主要研究成果如下：.（1）颗粒污泥在Pd(II)浓度为50-200mg/L，Pd/生物量比为1/40、1/20、3/40、1/10条件下，可以合成纳米钯；Bio-Pd存在于EPS及微生物细胞上，与微生物细胞结合量占75.3%-95.3%，分布在细胞质、细胞壁、周质间隙；电子传递中间体蒽醌-2,6-二磺酸可以提高EPS中Pd(II)还原量。.（2）生物纳米钯抑制了AGS产甲烷（33.9-87.7%）及产酸活性（25.8-53.0%），降低了AGS中微生物多样性，对细菌菌群结构影响大于古菌；氢营养型产甲烷菌相比乙酸型产甲烷菌更加敏感；为保持Pd-AGS微生物及化学催化特性，在还原过程中需要控制Pd(II)的浓度<100mg/L及最终载钯量（<4.4 wt% of Pd）。.（3）探讨了Pd-AGS降解卤代物双氯芬酸（DCF）和碘海醇反应条件、影响因素及过程机制，Pd-AGS相比对照AGS提高了DCF和碘海醇降解速率（最大提高了18倍及99倍）；电子供体效率顺序为：氢气>甲酸盐>葡萄糖>乙酸盐；Pd-AGS具有自发酵产氢激活纳米钯的功能；在中性条件下，去离子水、PBS、Na2SO4溶液中，Pd-AGS具有较高的降解DCF活性；氯离子、碘离子和硫离子会降低Pd-AGS活性；用去离子水洗涤可以再生Pd-AGS活性。