Nano-TiO_2 Enhanced Photofermentative Hydrogen Produced from the Dark Fermentation Liquid of Waste Activated Sludge

摘要

After anaerobic dark fermentation of waste activated sludge (WAS) for hydrogen production, there are a large number of organic compounds including protein, potysaccharide, and volatile ratty adds left in the dark fermentation liquid, which can be further bioconverted to hydrogen by photofermentarJon techniquea. In this study, the enhancement of photofermentative hydrogen produced from WAS dark fermentation liquid by using nano-TiO_2 is reported. First, high concentration of NH~4+-N in the dark fermentation liquid was observed to inhibit the photofermentative hydrogen production, and its removal was essential. Then the effect of nano-TiO2 on photofermentative hydrogen generation was investigated, and the addition of 100 mg/L nano-TiO_2 increased hydrogen by 46.1%. Finally, the mechanisms for nano-TiO_2 improving hydrogen production were investigated. It was found that nano-TiO_2 improved the decomposition of protein and polysaccharide to small- molecule organic compounds and promoted the growth of photosynthetic bacteria and the activity of nitrogenase but decreased the H_2-uptake hydrogenase activity.