【作者】 任宏宇；

【导师】 任南琪；

【作者基本信息】 哈尔滨工业大学 ， 环境科学与工程， 2011， 硕士

【摘要】 针对连续流光发酵制氢过程中底物利用效率、生物持有量和光能转化率低的技术难点,本文首次采用活性炭纤维（activated carbon fiber, ACF）固定化光发酵细菌,并应用于产氢研究。阐明了ACF的处理方法、浓度﹑长度、比表面积等同光发酵产氢之间的内在规律和联系,确定了最佳产氢条件。并探索将改性ACF作为载体应用于光发酵厌氧流化床制氢反应器进行连续流试验研究,建立有效的光发酵产氢调控策略,以期为生物制氢的规模化生产提供理论和技术指导。活性炭纤维有着良好的生物相容性和固定化产氢性能,比产氢率随着活性炭纤维比表面积的增加而增加,过大的长度和浓度都会对产氢有抑制作用。其产氢最佳参数为:比表面积1500 m²/g,长度1 mm,浓度0.8 g/L。间歇试验最大比产氢率为3.05 molH₂/mol乙酸,比传统载体（陶粒和活性炭）高12.4⁴7.3 %,结果证实了活性炭纤维是一种有效的光发酵细菌固定化载体。HNO3改性活性炭纤维的固定化产氢性能要明显优于KOH或H₂O₂改性活性炭纤维,HNO3改性的最佳处理浓度浓度为6 mol/L,处理时间为1 h,间歇试验最大产氢速率达35.94 ml/L/h,最大比产氢率高达3.30 molH₂/mol乙酸,比产氢率同对照试验相比提高了约36 %。活性炭纤维表面含氧官能团含量对产氢有重要影响。HNO3改性可显著的改变活性炭纤维表面C、N、O三种元素比例,使含氧官能团含量明显上升。研究表明,改性后活性炭纤维表面主要有C-OH、C=O和C-OOH三种官能团,其中C=O含量对细菌固定化起着决定性作用。在光发酵厌氧流化床制氢反应器的连续流运行中,HRT、初始pH、碳源、氮源和光照强度对产氢影响显著,过高的HRT、碳源、氮源和光照强度对产氢均有抑制作用。其中,初始pH对反应器产氢的影响最为显著,在初始pH=6.0时产氢延迟期延长至3天,且比产氢率和产氢速率大幅降低。光发酵厌氧流化床制氢反应器的最佳运行条件为:HRT 48 h,碳源浓度50 mmol/L,氮源浓度10 mmol/L,初始pH 7.0,光照强度4000 lux。其最高比产氢率为2.26 molH₂/mol乙酸,最高产氢速率为25.8 mlH₂/L/h。更多还原

【Abstract】 The low biomass, utilization rate of substrate and light conversion efficiency were the main barriers in continuous photo-hydrogen production. Hence, in this paper, a novel bio-carrier, activated carbon fiber, was firstly applied to immobilize the photo-fermentation bacteria for photo-hydrogen production and to overcome the above problems. The optimum amount, length, specific surface area and modified method of ACF were ascertained, and then the modified ACF was used in the photo-hydrogen producing anaerobic fluidized bed reactor. The optimal operation and control strategy of the reactor were established, which could provide the theory and the technical guidance for the development of bio-hydrogen production.The results showed that ACF was an excellent immobilized carrier for photo-fermentation bacteria with good biocompatibility and high immobilization ability. The hydrogen production increased with increasing the specific surface area, but the hydrogen production was inhibited when the amount and length of ACF were too high. When the specific surface area, length and amount of ACF was 1500 m²/g, 1 mm and 0.8 g/L in the batch tests, the maximum hydrogen yield of 3.05 molH₂/mol acetate was obtained, which was about 12.4⁴7.3 % higher than that of the traditional carriers（clay and activated carbon）. These demonstrated that ACF was an ideal carrier for the bacterial immobilization.The hydrogen production of HNO3 modified ACF was much better than those KOH and H₂O₂ modified ACF. The optimal concentration of HNO3 modification was 6 mol/L when the reaction time was 1 h. The maximum hydrogen production rate was 35.94 ml/L/h and the maximum hydrogen yield was 3.30 molH₂/mol acetate, which was 36 % higher than the control.The content of surface oxygenic functional groups had strong influence on the photo-hydrogen production. After HNO3 modification, the content of carbon, oxygen and nitrogen were changed visibly and meanwhile surface oxygenic functional groups increased. The main oxygenic functional groups on the ACF surface were C-OH, C=O and C-OOH, and C=O played a decisive role in the bacterial immobilization and hydrogen production.The hydrogen production of anaerobic fluidized bed reactor was restrained when HRT, acetate concentration, glutamate concentration and light intensity were in high level. The initial pH was the most important factor in influencing hydrogen production. When initial pH was 6.0, the hydrogen yield and hydrogen production rate were both decreased greatly and the hydrogen production was observed until 72 h. The optimum conditions of the reactor with the best hydrogen production performance as follows: HRT 48 h, acetate concentration 50 mmol/L, glutamate concentration 10 mmol/L, initial pH 7.0 and light intensity 4000 lux. The maximum hydrogen yield and hydrogen production rate of the reactor were 2.26 molH₂/mol acetate and 25.8 ml/L/h, respectively.更多还原