ZHANG Kaixuan1,3, ZHANG Chipeng1,2*, WU pan1,2, HUANG Chenchen1, CHEN Shuang1,3, LUO Jianglan1, LIU Fengzhu1
(1.College of resources and Environmental Engineering, Guizhou University, Guiyang 550025,China;
2.Key Laboratory of Karst Georesources and Environment, Ministry of Education, Guiyang 550025,China;
3.Guizhou Karst Environmental Ecosystems Observation and Research Station, Ministry of Education, Guiyang 550025,China; )
Abstract：In order to study the effect of iron-reducing microorganisms on soil colloids regulating the geochemical behavior of arsenic (As), iron-reducing bacteria Geobacter metallireducens were selected to act on 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 action of iron-reducing bacteria, which was helpful to form a strong reducing environment; when the soil colloid was sterile, the increase in the production and release of Fe(II) in the soil had a negative effect on As(V) The adsorption capacity of soil colloids gradually weakened; the maximum adsorption capacity of As(V) by soil colloids was 6.14 mg/kg lower than that of the sterile group when iron-reducing bacteria were present, but with the increase of anaerobic treatment time, the adsorption of As(V) capacity is increasing. 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.
Key words：Iron-reducing bacteria; soil colloid; iron; arsenic; migration and transformation
EARTH AND ENVIRONMENT Vol.51, No.1, Tot No.351, 2023, Page 108
