Bio-electrochemical Effect on Hydrogenotrophic Sulfate Reduction Stimulated by Electrical Field in the Presence of H2 Under Atmospheric Pressure
常压供氢体系电场强化硫酸盐还原生物-电化学效应研究

Mierobial sulfate reduction rate is limited with H_2 as electron donor. In order to improve hydrogenotrophic sulfate reduction under normal atmospheric H_2 pressure, a bio-electrochemical system with direct current was designed and performed in this study. Results indicates that sulfate reduction rate (SRR) increases with the augment of current intensity under lower current intensity ( I≤1.50 mA) . When optimum current intensity of 1 .50 mA is applied, the SRR is 1.7 to 2.1 times higher than that of the control reactor. The synergistic effect of electrochemistry and microbiology on sulfate reduction varies at different current intensity. Under the condition of /I≤1.50 mA, the most probable mechanism of SRR increase is that electric or magnetic field stimulates the proliferation of sulfate-reducing bacteria (SRB) and the activity of the enzymes. When / is higher than 1.50 mA, the activity of SRB is inhibited, resulting in lower reduction rate compared with that at lower current. If controlling the cathode potential tower than -0.69 V and H_2 partial pressure 1.01 × 10~5 Pa, electro-catalytic sulfate reduction process takes place with H_2 as reductant in this bio-electrochemical system. However, the overall reduction rate is still lower than that when I= 1.50 mA is applied, and additionally the energy consumption is much higher. Therefore, electric field of low intensity can enhance hydrogenotrophic sulfate reduction in the presence of H_2 under atmospheric pressure.