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近几十年来,河流水体受到的污染越来越严重[1],逐渐威胁到我们的生活,而底泥作为河流水体中污染物最大的“汇”与最大的“源”,其危害巨大。美国的大湖地区、德国的汉堡港、莱茵河流域以及荷兰的阿姆斯特丹港口等地区的底泥中含有大量的污染物,对环境造成严重污染[2],并且该污染为二次污染,不仅威胁水体中的植物和动物,甚至会危害人类健康[2-4]。随着国家对水体污染的治理越来越重视,河流水体环境得到改善,但底泥中大量的污染物仍是一个巨大的隐患[5]。现阶段有越来越多针对河流底泥污染物治理的措施与方法,如传统底泥污染治理方法中的物理方法、化学方法及生物生态方法等,这些方法有一定的适用性,但成本较高。考虑到目前能源危机不断凸显,更加节能、有效、适用的治理方法成为底泥污染治理的研究热点。
沉积型微生物燃料电池(SMFC)是将阳极置于厌氧的底泥中,阴极悬在底泥上方的好氧水体中,通过阳极表面微生物的代谢作用,使得底泥中的有机物发生厌氧降解,产生电子和质子,电子通过外接导线传递给阴极附近水体中的氧化性物质。同时,产生的质子通过底泥和上覆水体传递到阴极,阴极附近的氧化性污染物得到电子后会与质子反应,从而有效去除底泥及上覆水体中污染物。由于阴阳极之间形成了闭合回路,因此SMFC还可以产生电能用于其他方面,节约成本[6-8]。
SMFC作为近十几年发展的技术,特殊的结构使其在河流湖泊底泥原位修复上有较大的潜力。Han et al用SMFC实现了上覆水体中硝酸盐和Cr(Ⅵ)的同步去除[9]用SMFC实现了上覆水体中硝酸盐和Cr(Ⅵ)的同步去除。目前的研究还集中在利用SMFC去除各类重金属,关于优化SMFC参数去除Cr(Ⅵ)的研究内容较少。基于此,本文通过探讨盐酸预处理后的SMFC在不同阴极材料、不同外接电阻下对Cr(Ⅵ)去除的影响,以期望得到底泥中Cr(Ⅵ)的去除机制。
沉积型微生物燃料电池对污染底泥中重金属Cr(Ⅵ)去除的研究
Research of heavy metal Cr(Ⅵ) removal in contaminated sediment by sediment microbial fuel cells
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摘要: 文章探究了沉积型微生物燃料电池(sediment microbial fuel cells, SMFC)对阳极底泥中Cr(Ⅵ)的去除效果。通过设置对照试验,比较不同阴极材料、不同外接电阻对Cr(Ⅵ)去除的影响,探究底泥中Cr(Ⅵ)的去除机制。结果表明:底泥中Cr的去除主要发生在阴极上,其主要机制为 Cr(Ⅵ)从阳极迁移到阴极,并在阴极上作为电子受体被还原成Cr(Ⅲ);当阴极为碳刷,外电阻为1 000 Ω时,底泥中Cr的去除率最高,为27.4%。当阴极为碳毡,外电阻为100 Ω时,底泥中Cr的去除率只有10.5%,但其都大于自然状态下底泥中Cr的去除率; SMFC在阴极去除Cr(Ⅵ)的同时可在阳极去除底泥中的有机质。因此用SMFC来去除Cr等重金属的方法值得进一步研究。
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关键词:
- 沉积型微生物燃料电池 /
- 重金属去除 /
- 铬 (Ⅵ)
Abstract: This article mainly investigates the removal effect of sediment microbial fuel cells (SMFC) on Cr(Ⅵ) in the anode sediment. According to the comparison experiment, the effects of different cathode materials and different external resistances on the removal of Cr(Ⅵ) and the mechanism of Cr(Ⅵ) removal in sediments are analyzed. The results show that the removal of Cr in the sediment mainly occurs on the cathode, and the main mechanism is that Cr(Ⅵ) migrates from the anode to the cathode. Cr(Ⅵ) is reduced to Cr(Ⅲ) as an electron acceptor on the cathode. The removal rate of Cr is the highest with the carbon brush cathode and a 1 000 Ω external resistance, and the rate is 27.4%. When the cathode is carbon felt and the external resistance is 100 Ω, the removal rate is only 10.5%. However, they are greater than the removal rate of Cr under natural conditions. SMFC can also remove the organic matters in the anode sediment. Therefore, the method of using SMFC to remove heavy metals such as Cr is worthy of a further study.-
Key words:
- sediment microbial fuel cell /
- removal of heavy metal /
- Cr(Ⅵ)
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表 1 对照试验各参数
组别 阳极材料 阴极材料 外接电阻 1 碳毡 碳毡 开路 2 碳毡 碳刷 开路 3 碳毡 碳毡 1 000 Ω 4 碳毡 碳刷 1 000 Ω 5 碳毡 碳毡 100 Ω 6 碳毡 碳刷 100 Ω -
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