Xuejun Liu
Zhejiang University of Technology
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Featured researches published by Xuejun Liu.
Carbohydrate Research | 2012
Xuejun Liu; Ning Ai; Haiyan Zhang; Meizhen Lu; Dengxiang Ji; Fengwen Yu; Jianbing Ji
Lignocellulose and other carbohydrates are being studied extensively as potential renewable carbon sources for liquid biofuels and other valuable chemicals. In the present study, a simple, sensitive, selective, and reliable HPLC method using a photodiode array (PDA) detector and an evaporative light scattering detector (ELSD) was developed for the simultaneous determination of important sugars (D(+)-cellobiose, glucose, xylose, and arabinose), furfural and 5-hydroxymethylfurfural (5-HMF) in lignocellulose hydrolysate. The analysis was carried out on an Aminex HPX-87H column (250 mm × 4.6 mm, 5 μm particle size). Ultra-pure water with 0.00035 M H(2)SO(4) was used as the mobile phase with a flow rate of 0.6 mL/min. The temperature of the ELSD drift tube was kept at 50 °C, the carrier gas pressure was 350 kPa, and the gain was set at 7. Furfural and 5-HMF were quantified on a PDA detector at 275 nm and 284 nm, respectively. The sugar concentrations were determined by ELSD. This method was validated for accuracy and precision. The regression equation revealed a good linear relationship (r(2) = 0.9986 ± 0.0012) within the test ranges. The method showed good reproducibility for the quantification of six analytes in corncob hydrolysate, with intra- and inter-day variations less than 1.12%. This method is also convenient because it allows the rapid analysis of the primary products of biomass hydrolysis and carbohydrate degradation.
Bioresource Technology | 2014
Haiyan Zhang; Xuejun Liu; Meizhen Lu; Xinyue Hu; Leigang Lu; Xiaoning Tian; Jianbing Ji
In this work, the role of Brønsted acid for furfural production in biomass pyrolysis on supported sulfates catalysts was investigated. The introduction of Brønsted acid was shown to improve the degradation of polysaccharides to intermediates for furfural, which did not work well when only Lewis acids were used in the process. Experimental results showed that CuSO4/HZSM-5 catalyst exhibited the best performance for furfural (28% yield), which was much higher than individual HZSM-5 (5%) and CuSO4 (6%). The optimum reaction conditions called for the mass ratio of CuSO4/HZSM-5 to be 0.4 and the catalyst/biomass mass ratio to be 0.5. The recycled catalyst exhibited low productivity (9%). Analysis of the catalysts by Py-IR revealed that the CuSO4/HZSM-5 owned a stronger Brønsted acid intensity than HZSM-5 or the recycled CuSO4/HZSM-5. Therefore, the existence of Brønsted acid is necessary to achieve a more productive degradation of biomass for furfural.
Journal of Renewable and Sustainable Energy | 2016
Meizhen Lu; Xuejun Liu; Yongqiang Li; Yong Nie; Xianghong Lu; Dongshun Deng; Qinglong Xie; Jianbing Ji
Bi-functional catalysts consisting of platinum on aluminosilicate MCM-41 materials with Si/Al ratios between 10 and 30 were prepared via direct mixed-gel synthesis. The catalysts were tested in the hydrocracking of bio-alkanes, produced from biodiesel hydrodeoxygenation and composed of n-hexadecane and n-octadecane, for the production of bio-jet fuel. The effects of temperature, pressure, weight hourly space velocity (WHSV), and H2/n-paraffin weight ratio on bio-alkanes conversion and product distribution were examined. The conversion was found to be dependent on the acid strength of the catalyst supports which were proportional to the Al content. However, the catalyst selectivity decreased with the increasing Al content. The optimal Si/Al ratio, temperature, pressure, WHSV, and H2/n-paraffin weight ratio were determined to be 20, 330u2009°C, 2u2009MPa, 1u2009h−1, and 0.20, respectively. Under these conditions, the bio-alkanes conversion and kerosene/gasoline ratio in the product reached 65.62% and 1.96, respectively.
Journal of the Brazilian Chemical Society | 2018
Zhi Zheng; Tong Lei; Jun Wang; Yi Wei; Xuejun Liu; Fengwen Yu; Jianbing Ji
In this paper, we report the catalytic cracking of soybean oil for biofuel over γ-Al2O3/CaO composite catalysts. The influence of catalysts, cracking temperature and weight hourly space velocity (WHSV) on the products distribution were investigated. The maximum yield (70.0 wt.%) of biofuel with low acid value (6.7 mg KOH g) and oxygen content (5.6%), as well as high calorific value (44.2 MJ kg) was achieved over 35 wt.% γ-Al2O3/CaO at 480 °C and 3.72 h. The paper focused on the variation of biofuel composition and cracking pathway caused by γ-Al2O3/CaO composite catalysts via gas chromatography-mass spectrometry (GC-MS) and thermogravimetric (TG) analysis. Calcium oxide would react with fatty acid to yield calcium carboxylates at 300-350 °C, which were subsequently decomposed into hydrocarbons (57.9 wt.%) and ketones (22.6 wt.%) at 415-510 °C. As for 35 wt.% γ-Al2O3/CaO, the addition of γ-Al2O3 was beneficial to generate alkenes (38.2 wt.%), arenes (10.6 wt.%) and alcohols (12.3 wt.%) with ketones decreasing (16.5 wt.%) via γ-hydrogen transfer reaction and disproportination.
Industrial Crops and Products | 2012
Xuejun Liu; Meizhen Lu; Ning Ai; Fengwen Yu; Jianbing Ji
Industrial & Engineering Chemistry Research | 2013
Yumin Li; Jianbing Ji; Zhichao Xu; Guangquan Wang; Xiaohua Li; Xuejun Liu
Industrial & Engineering Chemistry Research | 2015
Yumin Li; Yongsheng Lu; Guangquan Wang; Yong Nie; Huijuan Ying; Jianbing Ji; Xuejun Liu
Archive | 2012
Jianbing Ji; Xuejun Liu; Yong Nie
Archive | 2012
Jianbing Ji; Xuejun Liu; Yong Nie
Separation and Purification Technology | 2017
Yumin Li; Yongsheng Lu; Xuejun Liu; Guangquan Wang; Yong Nie; Jianbing Ji