Zhiheng Li
China University of Petroleum
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Featured researches published by Zhiheng Li.
Bioresource Technology | 2018
Qingtai Chen; Dong Liu; Chongchong Wu; Kaisheng Yao; Zhiheng Li; Nan Shi; Fushan Wen; Ian D. Gates
An activity-tunable biocatalyst for Nannochloropsis sp. cell-walls degradation was prepared by co-immobilization of cellulase and lysozyme on the surface of amino-functionalized magnetic nanoparticles (MNPs) employing glutaraldehyde. The competition between cellulase and lysozyme during immobilization was caused by the limited active sites of the MNPs. The maximum recovery of activities (cellulase: 78.9% and lysozyme: 69.6%) were achieved due to synergistic effects during dual-enzyme co-immobilization. The thermal stability in terms of half-life of the co-immobilized enzymes was three times higher than that in free form and had higher catalytic efficiency for hydrolysis of cell walls. Moreover, the co-immobilized enzymes showed greater thermal stability and wider pH tolerance than free enzymes under harsh conditions. Furthermore, the co-immobilized enzymes retained up to 60% of the residual activity after being recycled 6 times. This study provides a feasible approach for the industrialization of enzyme during cell-walls disruption and lipids extraction from Nannochloropsis sp.
Green Chemistry | 2018
Zhiheng Li; Dong Liu; Zhuowu Men; Linhua Song; Yijun Lv; Pingping Wu; Bin Lou; Yadong Zhang; Nan Shi; Qingtai Chen
Tremendous attention has been paid to removal of N-/S-containing compounds from liquid fuel due to the necessity of reducing NOx and SOx emissions. In this work, the compatibility index (CI or PCI) was developed as a new criterion to evaluate the removal efficiency (Re) of quinoline, carbazole and dibenzothiophene (DBT) in deep eutectic solvents (DESs). For alkaline quinoline, acid–base extraction was pronounced, and ChCl/mandelic acid was the optimal extractant to achieve a removal efficiency of 99.2 wt% (CI = 0.37). For near-neutral carbazole and DBT, polarity compatible extraction was the predominant mechanism. The highest Re value of 94.9 wt% for carbazole removal was obtained in the ChCl/mandelic acid extractant (PCI = −0.044). DBT was difficult to remove directly because of its low molecular polarity. After adding H2O2, the desulfurization efficiency was found to increase to 99.1 wt% in the ChCl/p-toluenesulfonic acid extractant (PCI = 0.014). Furthermore, experiments with real diesel confirmed that the highest desulfurization and denitrification efficiency was 67.7 wt% and 63.7 wt%, respectively, in ChCl/p-toluenesulfonic acid. The compatibility index developed in this study has the potential to simplify the filtration operation of extractants and to intensify the removal efficiency of N-/S-containing compounds in the category of “green extraction”.
Archive | 2018
Ran Yu; Dong Liu; Bin Lou; Qingtai Chen; Yadong Zhang; Zhiheng Li
The composition of raw material was optimized by vacuum distillation. The carbonization behavior of two kinds of raw material was followed by polarizing microscope, softening point, carbon yield and solubility. Two kinds of mesophase pitch have been monitored by X-ray diffraction (XRD), Fourier transform infrared spectrometer (FTIR), elemental analysis and 1H nuclear magnetic resonance (1H-NMR). The analysis results suggested that raw material B (15wt% of A was distillated out and the residue named B) could form large domain mesophase pitch earlier. The shortened heat treat time favored the retaining of alkyl group in mesophase pitch and reduced the softening point of masophase pitch.
Archive | 2018
Dong Liu; Bin Lou; Ran Yu; Qingtai Chen; Zhiheng Li; Yadong Zhang
In this study, the selected aromatic-rich fraction derived from hydrocracking tail oil was carbonized and further improvement in the quality of resultant coke was achieved by promoting temperature at the solidification stage. In comparison with conventional process carried out isothermally and isobarically, the coupling analysis between formation and subsequent uni-axial orientation of mesophase textures during the controlled process was systematically discussed on the basis of the mutual relevance among mesophase texture evolution, gas evolution rate and solidification rate of intermediates. The results show that on the premise that formation of bulk mesophase, appropriate rate of gas evolution at a right time of solidification contributes to fine produces fine fibrous mesophase aligned uni-axially and less pores. Moreover, the intermediates with solidification index of 2∼6 are suitable for deformation induced by gas evolution.In this study, the selected aromatic-rich fraction derived from hydrocracking tail oil was carbonized and further improvement in the quality of resultant coke was achieved by promoting temperature at the solidification stage. In comparison with conventional process carried out isothermally and isobarically, the coupling analysis between formation and subsequent uni-axial orientation of mesophase textures during the controlled process was systematically discussed on the basis of the mutual relevance among mesophase texture evolution, gas evolution rate and solidification rate of intermediates. The results show that on the premise that formation of bulk mesophase, appropriate rate of gas evolution at a right time of solidification contributes to fine produces fine fibrous mesophase aligned uni-axially and less pores. Moreover, the intermediates with solidification index of 2∼6 are suitable for deformation induced by gas evolution.
Archive | 2018
Dong Liu; Qingtai Chen; Min Li; Bin Lou; Ran Yu; Zhiheng Li; Yadong Zhang
Chitosan can be applied in because of its excellent antimicrobial activity and abundant bio renewable and biodegradable resource. To better utilize this kind of native polysaccharide, it is still necessary to develop an efficient chitosan solvent system. Tn present study, 6 kinds of novel choline carboxylate ionic liquids (ILs) were developed. The solubility of chitosan in these H2O-ILs with different molar ratio were measured at 25 °C. The effect of the carboxylate anion of the ILs on chitosan solubility was estimated and found that the solubility of chitosan in the H2O-IL increased with the increasing of alkyl chain length in the anion. Moreover, the H2O-IL solution would not able to dissolve chitosan because the proton H was alternated by employing NH2 or OH group. The H2O-[Ch][CH3CH2CH2COO] (Rmol=6:1) solvent system exhibits highly efficient capacity for the dissolution of chitosan, and the solubility of chitosan reached up to 20.8 wt.%. From NMR measurement, these results could be explained by the possible interaction between carboxylate anion and chitosan and the strong hydration of the carboxyl group in the IL, suggesting that anionic structure have a significant impact on the dissolution of chitosan in the H2O-IL solvent system. Altogether, these results would provide an important evaluation indicator for screening the most suitable solvent system of chitosan.Chitosan can be applied in because of its excellent antimicrobial activity and abundant bio renewable and biodegradable resource. To better utilize this kind of native polysaccharide, it is still necessary to develop an efficient chitosan solvent system. Tn present study, 6 kinds of novel choline carboxylate ionic liquids (ILs) were developed. The solubility of chitosan in these H2O-ILs with different molar ratio were measured at 25 °C. The effect of the carboxylate anion of the ILs on chitosan solubility was estimated and found that the solubility of chitosan in the H2O-IL increased with the increasing of alkyl chain length in the anion. Moreover, the H2O-IL solution would not able to dissolve chitosan because the proton H was alternated by employing NH2 or OH group. The H2O-[Ch][CH3CH2CH2COO] (Rmol=6:1) solvent system exhibits highly efficient capacity for the dissolution of chitosan, and the solubility of chitosan reached up to 20.8 wt.%. From NMR measurement, these results could be explained by the po...
Separation and Purification Technology | 2017
Zhiheng Li; Pingping Wu; Xulian Hou; Dong Liu; Jianing Wang; Bin Lou; Xue Kong
Energy Conversion and Management | 2017
Linhua Song; Zhiheng Li; Daoxiang Zhang; Dong Liu; Pingping Wu; Qingyin Li
Energy & Fuels | 2017
Bin Lou; Dong Liu; Yajing Duan; Xulian Hou; Yadong Zhang; Zhiheng Li; Zhaowen Wang; Ming Li
Journal of The Taiwan Institute of Chemical Engineers | 2018
Ming Zhao; Dong Liu; Zhiheng Li; Hui Du; Jianing Wang; Kun Chen; Xue Kong; Jun Li
Fuel | 2018
Dong Liu; Bin Lou; Guangkai Chang; Yadong Zhang; Ran Yu; Zhiheng Li; Chongchong Wu; Min Li; Qingtai Chen