Key factors affecting microbial anode potential in a microbial electrolysis cell for H2 production

摘要

In order to optimize operations of microbial electrolysis cell (MEC) for hydrogen production,microbial anode potential (MAP) was analyzed as a function of factors in biofilm anode system,including pH,substrate and applied voltage.In the study MAP reflected the information when any factor became limiting for hydrogen production,such as pH＜6.0 or acetate less than 50 mg·L~(-1).Hydrogen generation started around anode potential of-250 mV ～ -300 mV.Higher hydrogen rate were obtained when MAP went down to -400 mV or lower.Biofilm anode could work normally between pH 6.5～7.0,with lowest MAP between 6.8～7.0. Applied voltage did not affect MAP much during hydrogen production.Potential analysis also showed that planktonic bacteria in suspended solution contributed to enhance electron transfer by reducing internal resistance and lowering minimum voltage needed for hydrogen production to some extent .