磷酸盐和碳酸盐对秸秆类生物质光发酵产氢的影响

摘要

为研究磷酸盐和碳酸盐对光发酵产氢过程的影响,该文主要以酶解预处理后的玉米秸秆为产氢基质,对不同浓度的磷酸盐(K2HPO4)和碳酸盐(NaHCO3)下的氢气产量、pH值、ORP值和产氢动力学结果进行分析.结果表明,当K2HPO4的浓度为10 mmol/L时,氢气产量为(40.65±0.35)mL/g,比对照组显著提高了28.48%,对光发酵产氢的促进效果最好;终pH值为6.37±0.02,显著高于对照组的6.06±0.03,能够有效缓冲反应体系的pH值.不同K2HPO4浓度下的产氢动力学特性结果表明,适当的K2HPO4浓度提高了最大产氢潜能和最大产氢速率,缩短了产氢延迟时间,当K2HPO4的浓度为10 mmol/L时,最大产氢潜能最大,和最大产氢速率较大,产氢延迟时间较短,分别是40.81 mL/g、1.87 mL/(h·g)和2.85 h.当NaHCO3浓度为5 mmol/L时,氢气产量为(37.46±1.40)mL/g,比对照组显著提高了18.39%,对光发酵产氢的促进效果最好;终pH值为6.26±0.04,显著高于对照组的6.06±0.03,能够有效缓冲反应体系的pH值.不同NaHCO 3浓度下的产氢动力学结果表明,适当的NaHCO 3浓度能够提高最大产氢潜能和最大产氢速率,但却会延迟光合细菌的产氢,当NaHCO3浓度为5 mmol/L时,最大产氢潜能和最大产氢速率最大,产氢延迟时间相对较短,分别是37.26 mL/g、1.92 mL/(h·g)和5.11 h.该研究可为秸秆类生物质光发酵生物制氢工艺提供参考.%For the study of phosphate and carbonate on the effect of photo-fermentation hydrogen production process, and based on the enzymatic hydrolysis of corn stalk pretreated for hydrogen producing substrate, in this paper, hydrogen production, pH value, ORP value and hydrogen production kinetics were analyzed under different concentrations of phosphate (K2HPO4) and carbonate (NaHCO3). The concentration of K2HPO4was respectively 5, 10, 15, 20, 40 and 60 mmol/L, the concentration of NaHCO3was respectively 5, 10, 15, 20, 25 and 30 mmol/L, and the untreated group was the control group. The results showed that phosphorus in K2HPO4was involved in biological growth, metabolism and energy transfer during microbial growth. Phosphorus is an important element in the process of biological growth and metabolism, while the phosphate also has a certain pH buffering capacity. The appropriate concentration of K2HPO4 can promote activities of photosynthetic bacteria to produce hydrogen, but also effectively buffer the pH value of the reaction system. When the concentration of K2HPO4 was 10mmol/L, the hydrogen yield was (40.65±0.35) mL/g, it increased significantly by 28.48% compared with control group, and the effect of promoting photo-fermentative hydrogen production was best. The final pH was 6.37±0.02, significantly higher than that of the control group of 6.06±0.03, indicating phosphate can effectively buffer the pH value of the reaction system. The results of kinetic characteristics of hydrogen production under different concentration of K2HPO4 showed that the suitable concentration of K2HPO4 increased the maximum hydrogen production potential and maximum hydrogen production rate, shortened the delay time of hydrogen production, when the concentration of K2HPO4 was10mmol/L, the maximum hydrogen production potential and the maximum hydrogen production rate were the highest, and the hydrogen production delay time was shorter, which was respectively 40.81 mL/g, 1.87 mL/(h·g) and 2.85 h. The appropriate concentration of NaHCO3 can promote photosynthetic bacteria to produce hydrogen, but also effectively buffer the pH value of the reaction system. When the concentration of NaHCO3 was 5 mmol/L, the hydrogen yield was (37.46±1.40) mL/g. It increased significantly by 18.39% compared with control group, and the effect of promoting photo-fermentative hydrogen production was best, and the final pH value was 6.26±0.04, which was significantly higher than that of the control group of 6.06±0.03. The results of kinetic characteristics of hydrogen production under different concentration NaHCO3 showed that the suitable concentration of NaHCO3 can improve the maximum hydrogen production potential and the maximum hydrogen production rate, but would delay hydrogen production, when the concentration of NaHCO3 was 5mmol/L. With this concentration, the maximum hydrogen production potential and the maximum hydrogen production rate were the highest, the hydrogen production delay time was relatively short, which was respectively 37.26 mL/g, 1.92 mL/(h·g) and 5.11 h. The study can provide a scientific reference for the further improvement of the technology of hydrogen production from straw biomass.