Ike M, Miyazaki T, Yamamoto N, Sei K, Soda S
Division of Sustainable Energy and Environmental Engineering, Osaka University, 2-1 Yamada-oka, Suita, Osaka 565-0871, Japan.
Water Sci Technol. 2008;58(5):1095-100. doi: 10.2166/wst.2008.462.
The presence of arsenic in groundwater has been of great public concern because of its high toxicity. For purification of arsenic-contaminated groundwater, bacterial oxidation of arsenite, As(III), with a chemical adsorption process was examined in this study. After As(III) oxidation to arsenate, As(V), arsenic is easily removable from contaminated groundwater because As(V) is more adsorptive to absorbents than As(III). By acclimation to As(III) of high concentrations, a mixed culture of heterotrophic bacteria with high As(III)-oxidizing activity was obtained from a soil sample that was free from contamination. With initial concentration up to 1,500 mg l(-1) As(III), the mixed culture showed high As(III)-oxidizing activity at pH values of 7-10 and at temperatures of 25-35 degrees C. The mixed culture contained several genera of heterotrophic As(III)-oxidizing and arsenic-tolerant bacteria: Haemophilus, Micrococcus, and Bacillus. Activated alumina was added to the basal salt medium containing 75 mg l(-1) As(III) before and after bacterial oxidation. Arsenic removal by activated alumina was greatly enhanced by bacterial oxidation of As(III) to As(V). The isotherms of As(III) and As(V) onto activated alumina verified that bacterial As(III) oxidation is a helpful pretreatment process for the conventional adsorption process for arsenic removal.
由于砷的高毒性，地下水中砷的存在一直备受公众关注。本研究考察了通过细菌将亚砷酸盐（As(III)）氧化并结合化学吸附过程来净化受砷污染的地下水。在As(III)氧化为砷酸盐（As(V)）之后，砷很容易从受污染的地下水中去除，因为As(V)比As(III)对吸附剂的吸附性更强。通过对高浓度As(III)进行驯化，从一个未受污染的土壤样品中获得了具有高As(III)氧化活性的异养细菌混合培养物。当初始浓度高达1500 mg l(-1) As(III)时，该混合培养物在pH值为7 - 10以及温度为25 - 35摄氏度的条件下表现出高As(III)氧化活性。该混合培养物包含几个属的异养As(III)氧化和耐砷细菌：嗜血杆菌属、微球菌属和芽孢杆菌属。在细菌氧化之前和之后，将活性氧化铝添加到含有75 mg l(-1) As(III)的基础盐培养基中。As(III)被细菌氧化为As(V)极大地增强了活性氧化铝对砷的去除效果。As(III)和As(V)在活性氧化铝上的等温线证实，细菌As(III)氧化是传统砷去除吸附过程的一个有益预处理过程。
