摘要
为研究铁还原微生物对土壤胶体调控砷(As)地球化学行为的影响机制,选用铁还原菌Geobacter metallireducens作用于土壤胶体,设计开展了土壤胶体的As吸附实验和不同pH条件下载As胶体的释放实验。结果表明:铁还原菌作用下胶体悬液Eh降至-222 mV,有助于形成强还原环境;当无菌作用时,土壤胶体随Fe(II)产生及释放量的增多对As(V)的吸附能力逐渐减弱;当有铁还原菌作用时,土壤胶体对As的最大吸附量较无菌组低6.14 mg/kg,但随厌氧处理时间的增加,其对As(V)的吸附能力呈增强趋势。在释放试验中,在pH=3条件下,铁还原菌对土壤胶体吸附As(V)的释放影响较弱,铁氧化物还原释放的As(III)仅占14.26%,以酸溶解为主;初始pH=7时总As释放量与悬液pH、Fe(II)含量呈线性关系,As(III)释放量较酸性条件提高6.7倍。该成果可为深入认识土壤微生物对As迁移转化的影响提供理论依据。
In order to study the influence mechanism of iron reducing microorganisms on the geochemical behavior of arsenic(As) regulated by soil colloid, iron-reducing bacteria, Geobacter metallireducens, was selected to react with soil colloids, and the As adsorption experiments of soil colloids and the release experiments of As colloids under different pH conditions were designed and carried out. The results showed that the Eh of the colloidal suspension decreased to-222 mV under the existence of iron-reducing bacteria, which was helpful to form a strong reducing environment;when the soil colloid was sterile, the adsorption capacity of soil colloid to As(V) decreases gradually with the increase of Fe(II) production and release;when iron-reducing bacteria were present, the maximum adsorption capacity of As(V) by soil colloids was 6.14 mg/kg, which was lower than that of the sterile group, however, the adsorption of As(V) capacity increased with the increase of anaerobic treatment time. In the release test, under the condition of pH=3, the effect of iron-reducing bacteria on the release of As(V) adsorbed by soil colloids was weak, and the As(III) released by iron oxide reduction accounted for only 14.26%, which was dominated by acid dissolution;When the initial pH=7, the total As release was simulated with the pH of the suspension and Fe(II) concentration, and the release of As(III) was 6.7 times higher than that in the acidic condition. This result can provide a theoretical basis for in-depth understanding of the influence of soil microorganisms on the migration and transformation of As.
作者
张凯璇
张翅鹏
吴攀
黄臣臣
陈爽
罗江兰
刘凤竹
ZHANG Kaixuan;ZHANG Chipeng;WU pan;HUANG Chenchen;CHEN Shuang;LUO Jianglan;LIU Fengzhu(College of Resources and Environmental Engineering,Guizhou University,Guiyang 550025,China;Key Laboratory of Karst Georesources and Environment,Ministry of Education,Guiyang 550025,China;Guizhou Karst Environmental Ecosystems Observation and Research Station,Ministry of Education,Guiyang 550025,China)
出处
《地球与环境》
CAS
CSCD
北大核心
2023年第1期108-116,共9页
Earth and Environment
基金
国家自然科学基金项目(41403088)
国家自然科学基金委员会-贵州省人民政府喀斯特中心项目(U1612442)。
关键词
铁还原菌
土壤胶体
铁
砷
迁移转化
iron-reducing bacteria
soil colloid
iron
arsenic
migration and transformation
