| Uranium is a radioactive and soluble element, the toxicity of U（VI） is significantly higher than the other valence. Semiconductor materials can generate reducing electrons on the basis of photo catalytic, with which the high valence cloud reduced to low valence. While, free electronic has a poor stability and micro-organisms can be used as an intermediate electron t ransfer to improve the efficiency of photo-electron.In this paper, surface water samples in a uranium mine western China have been collected and analyzed. The concentration of uranium in surface water is up to 72.2 mg/L. Total culturable bacterias are 6.4×103 cfu/g6.37×104 cfu/g under laboratory and the species of dominant strains are authenticated to be Delftia, Acidovorax, Acinetobacter and Kocuria.With an electrochemical cyclic voltammetry reduction method, the removal of uranium（VI） in uranyl ion aqueous is analyzed. The electrochemical behaviors of U（VI） in 0.1 M Na Cl solution are studied by cyclic voltammetry. The reduction processes of U（VI） to U（IV） can be decomposed into two steps and the electrochemical transfer process between U（IV） and U（VI） is diffusion control. The cyclic voltammetry results presented a constant potential reduction method for removing U（VI） from aqueous solution. U（VI） mainly crystalized into solid phases in the forms of UO2 and（UO2）6O2（OH）8·6H2O.With a FTO conductive glass, which is iscoated with semiconductor materials titanium dioxide, a study focused on the reducement U（VI） with photogenerated electrons has been conducted. Under open circuit potential, increasing exposure to light makes the current of experimental system increase. When suffer a photocatalytic reaction for 4 h, the content of U（VI） is almost reduced 58% and the purple mineral substances will be generated on the semiconductor electrode. Based on the XRD analysis, the black solid is UO2.The study focused on the role of mineral photoelectron mediated microbial on uranium valence transitionis two-chamber electrochemical analysis system. Studies have shown that photocatalytic semiconductor minerals can produce photo-generated electrons, which can effectively restore metabolite Fe（III） of A · ferrooxidans. The analysis results can explain that microorganisms can indirectly use electronic semiconductor. Under light conditions mineral photo-generated electrons make the U（VI） reduction rate be 20%. Logarithmic-after stabilization of the Kocuria tarda effect 20 h, U（VI） reduction efficiency is 26%. Mineral photo-generated electron mediated the Kocuria can make the reduction efficiency be up to 56%. Both the microorganisms and the improvement of photogenerated electrons reduction efficiency have a synergistic effect on the reduction of U（VI）.Photocatalytic semiconductor mineral synergistic microbial is an environmentally, friendly and sustainable way for high heavy metals. The research in this paper has provided a theoretical basis for high state highly toxic metal. |
