Wudi Zhang

Efficacy of Ageratina adenophora extract and biogas fermentation residue against the cabbage aphid, Brevicoryne brassicae and an assessment of the risk to the parasitoid Diaeretiella rapae.

The mortality effects of crofton weed (Ageratina adenophora, (Asteraceae)) acetone extract and biogas fermentation residue on the cabbage aphid Brevicoryne brassicae, and the risk posed to its parasitoid Diaeretiella rapae, were studied. Laboratory trials demonstrated the insecticidal activity of both substances, and this was confirmed by field experiments in which reductions of 73 and 71% aphid populations were recorded 3 days after treatment for the acetone extract and the biogas fermentation residue, respectively. The results of a laboratory contact toxicity test on inert substrates for parasitoid adults, and calculation of the Hazard Quotient (HQ) ratio, indicate a low risk for D. rapae, with HQ being consistently below the trigger value of 2.

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.

Study on preparing fatty acid by hydrolyzing rapeseed oil with lipase

Used Tween-80 as emulsifier, industrial lipase as catalyst to hydrolyze rapeseed oil and make mixed fatty acid. We discussed the enzyme concentration, substrate concentration, temperature and time on hydrolysis. Through the experiment, we found that when we used emulsifier which contains 2% oil in the system, we could get the optimal parameter for hydrolysis of waste oil from restaurants as follows: concentration of catalyst 5% (W/W), weight ratio of oil to water 1∶5 (W/W) , temperature at 40°C, and hydrolysis time is 32h. Under these conditions, the acid value of hydrolyzed rapeseed oil reached 175.8 mg KOH/g, and hydrolytic rate arrived at 91.5%.

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.

Research development of biofuels potential in Lao PDR

Many countries support and promote new technologies that make use of other renewable resources particularly in Lao PDR. Research on energy crops for biofuel production is in its initial step in Lao PDR, and has high potential for biofuels production from the byproduct of agricultural production, such as crop oils including Jatropha, palm oil, soybean and others that can be utilization as feedstock for biofuel production in Laos. The promotion of biodiesel and bio-ethanol production in Lao PDR is target driven rather than based on the overall land area suitable for agriculture. Plantations of agricultural crops suitable for biodiesel and bio-ethanol production may displace traditional crops and grazing areas and disrupt farm livelihoods. Lao government hoping a target of the total transportation energy consumption from biofuel will be achieved in the same period. Therefore, to completely achieve of the Lao governments goals and targets, Lao government has play important role to push up increasing of promotion for production and using of renewable energy. This paper is to study focus on status and risk of biofuels development and the feedstock potential for biofuels production in Lao PDR as well.

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.

Study on preparing fatty acid by hydrolyzing Jatropha Curcasl Oil with lipase

Used tween-80 as emulsifier, industrial lipase as catalyst to hydrolyze Jatropha Curcasl Oil and make mixed fatty acid. We discussed the enzyme concentration, substrate concentration, temperature and time on hydrolysis. Through the experiment, we found that when we used emulsifier which contains 2% oil in the system, we could get the optimal parameter for hydrolysis of waste oil from restaurants as follows: concentration of catalyst 4% (W/W), weight ratio of oil to water 1:4 (W/W), temperature at 40°C, and hydrolysis time is 32h. Under these conditions, the AV(acid value) of hydrolyzed rapeseed oil reached 163.2 mg KOH/g, and hydrolytic rate arrived at 89.6%.

Utilization of eupatorium adenophorum Spreng for bioenergy production

Eupatorium adenophorum Spreng can potentially be utilized in several bioenergy pathways. When directly combusted, it brings about soil fertility decline by removing organic matter from the field. When pretreated with microbial inoculum, it can be used as biogas fermentation material, which could increase the biogas production velocity. Eupatorium adenophorum Spreng is a promising potential biogas feedstock, whose rate of gas generation is 180 (m3·t-1TS) and fuel conversion efficiency is 12.37% at 30°C.

Study on material utilization efficiency and energy conversion efficiency of biogas fermentation by Eupatorium adenophorum Spreng

This experiment suggests that biogas-fermentation by pretreated Eupatorium adenophorum Spreng is a preferable approach compared with methane production followed by hydrogen production, only methane production, or only hydrogen production, due to its decreasing overall fermentation time, and increasing material utilization efficiency and energy conversion efficiency.

Experimental Study on Mesophilic Biogas Fermentation with Rice Straw Pretreated by Cellulase

This paper reported rice straw pretreated by cellulase can produce methane by anaerobic batch fermentation at 30°C with 6% of TS in 400 ml reactor. The results showed: Group B (time of cellulase treatment for 48 h) got the highest biogas production for 3188 ml, and group C (time of cellulase treatment for 24 h) got the gas production for 2718 ml. Both group B and group C biogas production increased compared with the control group(group A). With a Total Solids ( TS) gas production rate of 352 ml/gTS and 415 ml/gVS for group B, and 330 ml/gTS and 454 ml/gVS for group C, and 284 ml/gTS and 334 ml/gVS for control group. The energy conversion efficiency respectively were 49.96%, 46.40% and 39.90% for B,C and A group. So, pretreatment method B (48 h pretreatment by cellulase) was best for getting high biogas production and higher energy conversion efficiency.