微生物活动对砷污染湖泊沉积物中砷迁移转化的影响

发布时间：2018-03-24 23:30

本文选题：砷　切入点：微生物　出处：《云南大学》2016年硕士论文

【摘要】：絮凝-沉淀技术已成功地运用于一般性水体的砷污染治理中,但是对于由此沉降到沉积物中砷的迁移转化过程,却没有很好的数据来揭示。沉积物中砷是否会再次溶出形成二次污染?如果溶出,会通过什么方式溶出?在什么条件下溶出?这些问题都需要进一步去了解。前人众多的研究表明：沉积物中的微生物是影响沉积物中砷吸附／解吸的一个重要因素。本研究聚焦于经过絮凝沉淀处理的高砷沉积物中本土微生物对于砷的迁移转化的影响。研究通过室内模拟实验,分别考察了在好养／厌氧,添加碳源／不添加碳源等条件下微生物活动对于砷溶出的影响,并通过分析在此过程中溶解氧(DO)、pH、总有机碳(TOC)、铁(Fe)、锰(Mn)的变化,探讨微生物对砷迁移转化的影响机制。研究得出以下结论：(1)无论是好氧还是厌氧环境下,微生物活动都比非生物活动对砷溶出具有更明显的影响,表明微生物活动是主导铁盐所吸附的砷再溶出的关键因素。(2)在增加碳源并保持厌氧和接近中性的实验条件下,三价砷含量呈现出先升高后降低的趋势。而在好氧环境中,由于氧气与砷形成的砷氧双键影响砷酸根解离和促使pH升高,增强了砷酸根的溶出。(3)往水中添加可溶性有机碳的实验表明,有机碳既能促进非生物作用导致的砷溶出,也能促进微生物活动从而促进砷溶出。(4)在微生物活动影响下,伴随着砷的变化,铁、锰呈现周期性溶出,表明微生物活动不仅直接影响砷的形态转化,还通过铁、锰的微生物异化作用来影响砷的溶出。(5)微生物活动导致的砷溶出比非生物作用导致的砷溶出强度大且持续时间更长,但是非生物作用较微生物活动的作用更迅速。
[Abstract]:Flocculation-precipitation technology has been successfully applied to the treatment of arsenic pollution in general water bodies. But there is no good data to show whether the arsenic in the sediments dissolves again to form secondary pollution. If it dissolves, how will it be dissolved? Under what conditions? Many previous studies have shown that microbes in sediments are an important factor affecting the adsorption / desorption of arsenic in sediments. This study focuses on the high arsenic content treated by flocculation and precipitation. Effects of native microbes in sediments on arsenic transport and transformation. The effects of microbial activities on arsenic dissolution under the condition of aerobic / anaerobic, carbon source / no carbon source were investigated, and the changes of dissolved oxygen (DOA) pH, total organic carbon (TOC), total organic carbon (TOC), iron (Fe) and manganese (mn) were analyzed. The effect of microorganism on arsenic migration and transformation was discussed. The following conclusions are drawn: 1) in aerobic or anaerobic environment, microbial activity has more obvious effect on arsenic dissolution than abiotic activity. The results show that microbial activity is the key factor for arsenic adsorption and dissolution by iron salts.) under the experimental conditions of increasing carbon source and keeping anaerobic and neuter, trivalent arsenic content increases first and then decreases. However, in aerobic environment, the content of trivalent arsenic increases at first and then decreases in aerobic environment. The experiment of adding soluble organic carbon into water by arsenic double bond formed by oxygen and arsenic affected the dissociation of arsenate radical and promoted the increase of pH value, which indicated that organic carbon could promote the arsenic dissolution caused by abiotic action. It can also promote microbial activity and thus promote arsenic dissolution. (4) under the influence of microbial activities, iron and manganese dissolves periodically with the changes of arsenic, indicating that microbial activities not only directly affect the transformation of arsenic forms, but also through iron, The microbial dissimilation of manganese affects arsenic dissolution. 5) the arsenic dissolution caused by microbial activity is stronger and lasts longer than that caused by abiotic action, but the abiotic action is more rapid than that of microbial activity.
【学位授予单位】：云南大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：X524

【相似文献】