Comparison of dissolved organic matter from sewage sludge and sludge compost as electron shuttles for enhancing Fe(III) bioreduction
Comparison of dissolved organic matter from sewage sludge and sludge compost as electron shuttles for enhancing Fe(III) bioreduction
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污水污泥和污泥堆肥中溶解有机物作为电子穿梭增强 Fe(III) 生物还原的比较
DOI：
10.1007/s11368-009-0161-2
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发表时间：
2010-05-01
影响因子：
3.6
通讯作者：
Li, Fang-Bai
中科院分区：
文献类型：
--
作者：
Huang, De-Yin;Zhuang, Li;Li, Fang-Bai
污水污泥和污泥堆肥的利用是许多国家的普遍做法。污泥和污泥堆肥处理后的土壤表现出不同的理化性质，尤其是溶解有机质（DOM）组成对土壤DOM给电子能力（EDC）的影响。本文的目的是比较污水污泥和污泥堆肥中DOM的EDC对提高铁（III）生物还原的作用。希望本研究能为今后对土壤修复的进一步认识提供帮助。材料与方法分别从污水污泥和污泥堆肥中提取污泥DOM和堆肥DOM。采用分馏、CHNO/S分析、傅里叶变换红外光谱和紫外可见光谱以及循环伏安法测定样品的芳香烃化程度和腐殖化程度。为了确定它们的EDC在堆肥过程中是否被改变，样品被腐殖质还原菌，希瓦氏菌D14T还原，然后测定它们的EDC值。以FeCl3/Fe（柠檬酸盐）为电子受体，测定了样品的初始EDC值和电位EDC值。菌株D14T对不溶性Fe（III）氧化物的还原是由DOM介导的。结果与讨论污泥和堆肥DOM均含有氧化还原活性官能团，可以将电子传递到不溶性Fe（III）氧化物上，加速Fe（III）的生物还原。当FeCl3作为氧化剂时，它们的电位EDC分别达到0.25和0.50 meq/(mg C)。此外，它们的电子转移能力可以循环利用。结论在污泥堆肥过程中DOM腐殖质化程度增加，导致堆肥DOM的EDC大于污泥DOM。此外，在厌氧条件下，DOM介导的Fe（III）生物还原速率可以加快，这对土壤生物地球化学具有重要意义，因为它可以加快某些有毒金属和顽固性有机污染物的转化或降解速度。
PurposeLand utilization of sewage sludge and sludge compost is a common practice in many countries. Soils amended with sewage sludge and sludge compost display different physicochemical properties, especially in terms of dissolved organic matter (DOM) composition that affects the electron-donating capacity (EDC) of DOM in soils. The aim of this paper was to compare the EDC of DOM derived from sewage sludge and sludge compost for enhancing Fe(III) bioreduction. It is expected that this research could be helpful for further understanding of soil remediation in the future.Materials and methodsSludge and compost DOM were extracted from sewage sludge and sludge compost, respectively. Fractionation, CHNO/S analysis, Fourier-transform infrared and ultraviolet-visible spectroscopy, and cyclic voltammetry were then used to determine the degree of aromaticity and humification in the samples. To determine if their EDC was altered during composting, samples were reduced by the humic-reducing bacterium, Shewanella cinica D14T, after which their EDC values were determined. The initial and potential EDC values of the samples were measured using FeCl3/Fe(citrate) as an electron acceptor. The insoluble Fe(III) oxide reduction by strain D14T was mediated by DOM.Results and discussionBoth sludge and compost DOM contained redox-active functional groups that could shuttle electrons to insoluble Fe(III) oxide and accelerate Fe(III) bioreduction. When FeCl3 was used as an oxidizing agent, their potential EDC reached 0.25 and 0.50 meq/(mg C), respectively. In addition, their electron transfer ability could be recycled.ConclusionsThe degree of humification of DOM increased during sludge composting, which resulted in the EDC of compost DOM being greater than that of sludge DOM. Furthermore, the rate of Fe(III) bioreduction mediated by DOM could be accelerated under anaerobic conditions, which has important implications for soil biogeochemistry because it may accelerate the rate of some kinds of toxic metals and recalcitrant organic pollutants transformation or degradation.