87 / 2021-06-30 20:30:06

Effect of biochar and nanoscale zero-valent iron on biohydrogen production and electron balance in high load corn stover photo fermentation system

Biochar; Nanoscale zero-valent iron; Biohydrogen; Photo fermentation; High load.

The issue of global warming caused by greenhouse gases emission arouses considerable attention. Hydrogen is an ideal carrier with high calorific value and no pollution combustion. Among various production methods, biohydrogen production by photo fermentation is considered as a promising method with environment friendless and high substrate conversion efficiency. However, when the substrate loading is high, the accumulation of volatile fatty acids will cause acidification of photo-fermentative biohydrogen production system, resulting in the decline of photosynthetic bacteria activity and biohydrogen production performance. Hence, it is necessary to improve the stability and biohydrogen production of fermentation system with high substrate load. Biochar, with high porosity and specific surface area, has been widely used to enhance the buffering effect on anaerobic digestion system due to its eco-compatibility and low cost. Besides, the supplement of nanoscale zero-valent iron has been reported to enhance the activity of hydrogen producing bacteria and enzymes. In this work, the effects of biochar and nanoscale zero-valent iron on biohydrogen production and electron balance in high load corn stover photo fermentation system were studied and compared. The modified Gompertz model was applied, and biohydrogen yield, Redox potential, metabolites and electron balance were determined with corn stover load ranging from 5 g TS to 11 g TS. Results showed that the addition of nanoscale zero-valent iron showed better performance than the addition of biochar.