电场条件下的硫酸盐还原效应及pH/ORP响应

Sulfate reduction stimulated by an electric field and its correlation with pH and the ORP

针对氢气作为电子供体的硫酸盐生物还原速率缓慢的问题,采用附加直流电的方式强化。体系最佳电流强度为1.50mA,平均还原速率是微生物单独作用的1.7~2.1倍。当还原速率小于10m g/d时,氧化还原电位(ORP)值分布在0^-500mV,与硫酸盐还原效应之间的响应规律不明显。当还原速率为10~50m g/d时,ORP分布在-350^-450mV的较窄范围,表明ORP<-350mV时,ORP不再是影响还原速率的主要因素。pH为8~9.5、ORP为-350^-450mV为该研究体系硫酸盐还原的优势场。

The hydrogenotrophic sulfate reduction rate is very limited in most conditions. Here, a direct electrical current was used to promote sulfate reduction with H2 as the electron donor. The optimal current intensity of this system was 1.50 mA, with an average sulfate reduction rate（SRR） was 1.7-2.1 times higher than that of the control without electrical current. Increasing the pH to create a moderately alkaline environment for the bacteria significantly improved the sulfate reduction. When the daily average sulfate reduction rate was less than 10 mg/d, the oxygen reduction potentials （ORP） varied randomly from 0 to 500 mV. However, when the daily average SRR was 10- 50 mg/d, ORP distributed densely within the range of - 350 ～ - 450 inV. Thus, when the ORP〈- 350 mV, the ORP was no longer the dominant factor influencing the reduction process. The predominance field of this system for sulfate reduction lied in the domain of pH = 8 - 9.5 and ORP = - 350-450 mV.