Bioremediation of Cr(VI) in contaminated soils.
Bioremediation of Cr(VI) in contaminated soils.
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DOI：
10.1016/j.jhazmat.2005.01.018
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发表时间：
2005-05
影响因子：
13.6
通讯作者：
K. Krishna;L. Philip
中科院分区：
文献类型：
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作者：
K. Krishna;L. Philip
生物反应器-生物吸附系统异地处理六价铬污染土壤是一种新的修复方法。用不同的淋洗液对污染土壤中的六价铬进行淋洗，结果表明，溶液的pH值对解吸有很大的影响。在碱性条件下(pH=9)，浸出过程加快。虽然乙二胺四乙酸解吸势最大，但糖蜜(5g/L)也能洗脱72%的铬(VI)。利用污染土壤中的细菌分离株，在好氧和兼性厌氧条件下进行了铬(VI)还原研究。在好氧条件下，铬(VI)的还原程度略高于兼性厌氧条件。考察了不同给电子体对六价铬还原的影响。在所筛选的5个电子供体中，蛋白胨(10g/L)对铬(VI)的还原作用最大，其次是糖蜜(10g/L)。随着铬(VI)初始浓度的增加，完全还原所需的时间增加。然而，随着初始铬(VI)浓度的增加，比铬(VI)还原增加。硫酸盐和硝酸盐不与六价铬竞争接受电子。研制了一种生物反应器用于铬(VI)的脱毒。在水力停留时间为8h，初始浓度为50 mg/L的生物反应器中，铬(VI)的降解率可达80%以上。以灵芝为吸附剂，研制了一种脱除生物反应器出水中三价铬和过量电子供体的吸附柱。灵芝对铬(III)的吸附比容量为576 mg/g，该生物体系有望成为铬污染土壤异地生物修复的一种新方法。
Ex situ treatment of hexavalent chromium (Cr(VI)) contaminated soil using a bioreactor–biosorption system was evaluated as a novel remediation alternative. Leaching of Cr(VI) from the contaminated soil using various eluents showed that desorption was strongly affected by the solution pH. The leaching process was accelerated at alkaline conditions (pH 9). Though, desorption potential of ethylene diamine tetra acetic acid (EDTA) was the maximum among various eluents tried, molasses (5g/L) could also elute 72% of Cr(VI). Cr(VI) reduction studies were carried out under aerobic and facultative anaerobic conditions using the bacterial isolates from contaminated soil. Cr(VI) reduction was moderately higher in aerobic conditions than in facultative anaerobic conditions. The effect of various electron donors on Cr(VI) reduction was also investigated. Among five electron donors screened, peptone (10g/L) showed maximum Cr(VI) reduction followed by molasses (10g/L). The time required for complete Cr(VI) reduction was increased with increase in the initial Cr(VI) concentration. However, specific Cr(VI) reduction was increased with increase in initial Cr(VI) concentration. Sulfates and nitrates did not compete with Cr(VI) for accepting the electrons. A bioreactor was developed for the detoxification of Cr(VI). Above 80% of Cr(VI) reduction was achieved in the bioreactor with an initial Cr(VI) concentration of 50mg/L at an HRT of 8h. An adsorption column was developed using Ganoderm lucidum (a wood rooting fungus) as the adsorbent for the removal of trivalent chromium (Cr(III)) and excess electron donor from the effluent of the bioreactor. The specific Cr(III) adsorption capacity of G. lucidum in the column was 576mg/g. The new biosystem seems to be a promising alternative for the ex situ bioremediation of Cr(VI) contaminated soils.