Xingling Zhao

Increased energy production from sucrose by controlled hydrogen-producing fermentation followed by methanogenic fermentation

ABSTRACT To improve the low energy production efficiency of fermentative hydrogen production (FHP) and fermentative methane production (FMP), the two types of fermentation were effectively combined in this study. Using sucrose as feedstock, both successive fermentative production of hydrogen followed by methane (SFPHM) and successive fermentative production of methane followed by hydrogen (SFPMH) were performed to improve the energy production efficiency of the overall anaerobic process. The results showed that the energy conversion efficiency of SFPHM was 79.85% whereas that of SFPMH was only 43.12%. Therefore, SFPHM can significantly improve the energy production efficiency of traditional anaerobic biological treatment.

Optimization and kinetic study of methyl laurate synthesis using ionic liquid [Hnmp]HSO4 as a catalyst

Methyl laurate was synthesized from lauric acid (LA) and methanol via an esterification reaction using ionic liquids (ILs) as catalysts. The efficiencies of three different catalysts, 1-methylimidazole hydrogen sulfate ([Hmim]HSO4), 1-methyl-2-pyrrolidonium hydrogen sulfate ([Hnmp]HSO4) and H2SO4, were compared. The effect of the methanol/LA molar ratio, reaction temperature, reaction time and catalyst dosage on the esterification rate of LA was investigated by single-factor experiments. Based on the single-factor experiments, the esterification of LA and methanol was optimized using response surface methodology. The results showed that the most effective catalyst was the IL [Hnmp]HSO4. The optimal conditions were as follows: [Hnmp]HSO4 dosage of 5.23%, methanol/LA molar ratio of 7.68 : 1, reaction time of 2.27 h and reaction temperature of 70°C. Under these conditions, the LA conversion of the esterification reached 98.58%. A kinetic study indicated that the esterification was a second-order reaction with an activation energy and a frequency factor of 68.45 kJ mol−1 and 1.9189 × 109 min−1, respectively. The catalytic activity of [Hnmp]HSO4 remained high after five cycles.

Effective difference volumes of inoculum for methane production in anaerobic batch digestion by using casein

ABSTRACT Anaerobic digestion is one the most efficient technologies in waste and wastewater management for producing renewable energy and reducing greenhouse gas emission from animal manure. In this experiment procedure was use duplicate samples and controls in different volumes of inoculum (10%, 20%, 30%, and 40%, respectively) were mixed with the same volume 10 g of casein, which the experimental results of the daily methane productions in duplicate samples were also slightly increased during the first day although out the final day of biodegradability process. The specific methane value in sample 40% was a highest methane volume about 86 ml/gVS when compared with the other samples (10%, 20% and 30%, respectively). However, the methane yield among samples was considerably lower than theoretical by comparison. Therefore, the differential volumes of inoculum used for a BMP test were influence the methane production of anaerobic batch digestion process, and these difference inoculum volumes were significantly effective or not were depending on the substrate used. This experimental study was to measure the methane production form different volumes of inoculum, and to evaluate the influence of inoculum by mixing 10g of casein as the substrate in BMP test processes.