摘要
Cr(Ⅵ)和硝酸盐是地下水中常见的复合污染物,且有可能通过迁移扩散至低渗透区而导致其修复问题被忽视.利用Shewanella oneidensis MR-1作为功能微生物,分别研究了摇瓶和非均质模拟装置中两种污染物的协同异化还原过程.结果表明:摇瓶实验中,Cr (Ⅵ)的去除主要依赖于初始菌浓度,而受硝酸盐浓度、电子供体乳酸盐浓度的影响较小.反之,硝酸盐的还原则明显受到Cr (Ⅵ)的抑制,当Cr(Ⅵ)浓度在0到0.02mmol/L时,其一级动力学还原速率从0.635h^(-1)降至0.164h^(-1).同时,乳酸盐氧化也明显受到Cr(Ⅵ)的抑制,表明Shewanella oneidensis MR-1的代谢过程可能受到了Cr(Ⅵ)的毒性干扰.在非均相装置实验中,Cr(Ⅵ)进水浓度小于等于5mg/L(约0.1mmol/L)时,15d基本可以完全去除,对应硝酸盐去除60%左右;当Cr(Ⅵ)浓度增至10mg/L (约0.2mmol/L)时,Cr(Ⅵ)和硝酸盐的去除率分别降至40%和50%左右.装置内截留的Cr(Ⅵ)还原产物以Cr(OH)_3为主,硝酸盐的还原产物以氨为主.
Cr(VI)and nitrate were common contaminants in groundwater,which can be transported into low permeability zones thus the remediation issues was ignored.Shewanella oneidensis MR-1 was used to reduce both Cr(VI)and nitrate in batch and heterogeneous column experiments.Results from batch experiments showed that Cr(VI)reduction was mainly depended on initial biomass concentration,but was hardly affected by concentrations of nitrate and lactate.On the contrary,nitrate reduction was significantly inhibited by Cr(VI).The first-order reduction rate constant of nitrate reduction decreased from 0.635h^(-1) to 0.164h^(-1) when Cr(VI)concentration increased from 0 to 0.02mmol/L.At the same time,lactate oxidation rate was also inhibited by high Cr(VI)concentration,which was possible due to the metabolism of Shewanella oneidensis MR-1 was affect by Cr(VI)toxicity.In the column experiment,when the influent Cr(VI)concentration was≤5mg/L(about 0.1mmol/L),it could be completely removed in 15 days,and about 60%of nitrate was reduced correspondingly.When Cr(VI)concentration increased to 10mg/L(about 0.2mmol/L),about 40%Cr(VI)and 50%nitrate were reduced,respectively.The reduction products trapped within the column for Cr(VI)and nitrate were Cr(OH)3 and ammonia,respectively.
作者
贡玉凤
GONG Yu-feng(State Environmental Protection Engineering Center for Urban Soil Contamination Control and Remediation,Shanghai Academy of Environmental Sciences,Shanghai 200233,China;College of Environmental Science and Engineering,State Key Laboratory of Pollution Control and Resources Reuse,Tongji University,Shanghai 200092,China)
出处
《中国环境科学》
EI
CAS
CSCD
北大核心
2024年第5期2473-2482,共10页
China Environmental Science
基金
国家自然科学基金项目(41671488,42207469)。
