Co-reporter:Jiapeng Li;Qihui He;Renfu Xu
Chinese Journal of Chemistry 2015 Volume 33( Issue 11) pp:1259-1268
Publication Date(Web):
DOI:10.1002/cjoc.201500498
Abstract
In this paper silica nanoparticles with covalently grafted polymer chains were incorporated into bisphenol A dicyanate ester (BADCy) to prepare composites which resulted in improvements in the mechanical and thermal properties. Fourier-transform infrared (FT-IR) spectroscopy transmission electron microscopy (TEM) and thermogravimetric analysis (TGA) were employed to examine the surface functionalization of silica nanoparticles. The effects of functionalized SiO2 (F-SiO2) on the curing reactivity mechanical and thermal properties of BADCy resin were investigated systematically. The curing reaction of the system was facilitated with the addition of F-SiO2. Meanwhile compared with the neat resin the incorporation of appropriate content of modified F-SiO2 can enhance the mechanical properties including impact flexural strengths and fracture toughness KIC of BADCy resin. In addition the thermal stability of BADCy/F-SiO2 nanocomposites is also superior to that of pure BADCy resin.
Co-reporter:Qihui He, Dong Xie, Renfu Xu, Tongwei Wang, Baixing Hu
Fuel 2015 Volume 159() pp:40-44
Publication Date(Web):1 November 2015
DOI:10.1016/j.fuel.2015.06.071
The effects of blending sewage sludge on the properties of coal–sludge slurry (CSS), such as solid loading, apparent viscosity, rheological behaviour and stability, were systematically investigated. The size and morphology of particles, and grinding efficiency were analyzed. The experimental results showed that adding sewage sludge can improve the grinding efficiency and stability of slurry. CSSs prepared from Yanzhou coal, Jiangxinzhou sewage sludge and Yangzi sewage sludge exhibit pseudo-plastic behaviour with an apparent viscosity decreasing with increasing shear rate. Both CSSs, containing 10 wt% Jiangxinzhou sewage sludge and 15 wt% Yangzi sewage sludge, with about 60 wt% solid loading and 1200 mPa s apparent viscosity, are suitable for theirs handling in preparation, transport, storage, atomization, and combustion processes.
Co-reporter:Chunhai Liu;Qihui He;Zheng Zhang;Yangyang Su;Renfu Xu
Chinese Journal of Chemistry 2014 Volume 32( Issue 5) pp:410-416
Publication Date(Web):
DOI:10.1002/cjoc.201400146
Abstract
Four BrØsted acid ionic liquids (ILS) [MMP][DMP], [MEP][DEP], [HMP][DMP] and [HEP][DEP] were synthesized and used as extractants for desulfurization of aromatic sulfur compounds in model oil. The mutual solubility of four ILs were investigated. The extraction equilibrium of four ILs could be reached in as soon as 5 min and the extraction capability followed the order [MMP][DMP]>[MEP][DEP]>[HEP][DEP]>[HMP][DMP]. The S extraction showed the highest efficiency under the conditions of 30°C, 30 min and 1:1 (V/V) IL:oil. Under the optimal condition, 70.9% of thiophene (TS), 76.9% of benzothiophene (BT) and 87.5% of dibenzothiophene (DBT) in n-octane could be efficiently removed by [MMP][DMP]. The multiple extraction and regeneration performance of [MMP][DMP] for TS was also investigated and the results were satisfying. These results suggest that [MMP][DMP] has the best extraction capability and can serve as a promising solvent for extractive desulfurization of fuel oils.
Co-reporter:Bo Liu, Qihui He, Zihao Jiang, Renfu Xu, Baixing Hu
Fuel 2013 Volume 105() pp:293-300
Publication Date(Web):March 2013
DOI:10.1016/j.fuel.2012.06.046
Coal ash fusion characterization and the ash fusion temperatures (AFTs) are important parameters for coal industry. Previous research has proved that the AFTs are correlated with the chemical composition of coal ash samples. In this paper, a five-component SiO2–Al2O3–CaO–Fe2O3–K2O system is set. The AFTs of 34 synthetic ashes were measured in a carbon atmosphere, and the trends of the AFTs analyzed. Different from other studies, X-ray diffraction (XRD) and scanning electron microscope (SEM) were combined to explore the relationships between the measured AFTs and the mineral composition, morphology and microstructure of ash samples. Furthermore, the effect of the element valence state is also taken into account and X-ray photoelectron spectrometer (XPS) is used to analyze it firstly. The results show that the AFTs decrease with the increasing Fe2O3 content and silica-to-alumina (S/A) ratio. However, for the effect of CaO content, the AFTs reach a minimum value and then increase once again. Furthermore, the AFTs show no significant change as the K2O content varies. At last, all the conclusions found from the synthetic samples are also applicable for the seventeen bituminous coal ashes collected locally and abroad.Highlights► This study is based on a five-component SiO2–Al2O3–CaO–Fe2O3–K2O system. ► This study uses a combination of XRD and SEM techniques. ► The effects of CaO, Fe2O3, K2O and silica-to-alumina ratio on AFTs are studied. ► Conclusions found from synthetic ashes are applicable to real coal ashes.
Co-reporter:Yiwen Hu, Qihui He, Zheng Zhang, Naidong Ding and Baixing Hu
Chemical Communications 2011 vol. 47(Issue 44) pp:12194-12196
Publication Date(Web):30 Sep 2011
DOI:10.1039/C1CC14153H
With stoichiometric H2O2 as oxidant, dibenzothiophene (DBT) is oxidized to its corresponding sulfone with high efficiency, catalyzed by a sub-valence heteronuclear peroxotungstate, [C18H37N(CH3)3]4[H2SeIV3W6O34], under mild biphase conditions and the catalyst shows remarkable selectivity of catalytic oxidation towards DBT, cinnamyl alcohol and quinoline.
Co-reporter:Jiawei Fu, Qihui He, Rui Wang, Bo Liu, Baixing Hu
Colloids and Surfaces A: Physicochemical and Engineering Aspects 2011 Volume 375(1–3) pp:136-140
Publication Date(Web):5 February 2011
DOI:10.1016/j.colsurfa.2010.11.078
Mesoporous sieves MCM-41 modified by trimethylchlorosilane and methyltrimethoxysilane were prepared by postsynthesis grafting (PSG) process and further characterized by thermogravimetric (TG) analysis, FTIR spectroscopy, and nitrogen sorption experiments. Adsorption experiments of phenol and hydroquinone in solutions were carried out. The surface properties of silica were found to be the key factors for the phenol compound adsorption in low concentration solutions. Results showed that the modification of alkyl groups did enhance the loading amount of phenol by employing both the van der Waals force and hydrogen bonds, but it also reduced the adsorption amount of hydroquinone by covering oxygen atoms and hydroxyl groups on the surface when hydrogen bond was a dominant factor due to the specific structure of hydroquinone.Graphical abstractResearch highlights▶ MCM-41 is modified by desired organic groups with different coverages. ▶ Surface properties play the dominant role at low concentration. ▶ Both surface modification and adsorbate structure exert influence to adsorption. ▶ Concentration of solution is the key factor at high concentration.
Co-reporter:Jing Liu;Naidong Ding;Renfu Xu;Qihui He;Jian Shen
Polymer Engineering & Science 2011 Volume 51( Issue 7) pp:1404-1408
Publication Date(Web):
DOI:10.1002/pen.21952
Abstract
Hydroxyl-terminated polybutadiene (HTPB) rubber was used as a modifier for bisphenol A dicyanate ester (BADCy) to improve its toughness. The effect of catalyst on the curing behavior of the resin and the curing techniques were developed by differential scanning calorimetry. The dynamic mechanical analysis, thermogravimetry analysis, and tensile test were used to study the thermal behavior, mechanical properties, and dynamic mechanical performance of the modified BADCy resins. Results show that addition of HTPB resulted in improved toughness while maintaining relatively good thermal stability. Additional, phase separation phenomenon was confirmed by the analysis of scanning electron microscope. For the toughening of the resin, the main toughening mechanism is shear yielding and crack branching. POLYM. ENG. SCI., 2011. © 2011 Society of Plastics Engineers
Co-reporter:Jiawei Fu, Qihui He, Bo Liu, Jingjing Zhang, Baixing Hu
Colloids and Surfaces A: Physicochemical and Engineering Aspects 2010 Volume 369(1–3) pp:113-120
Publication Date(Web):20 October 2010
DOI:10.1016/j.colsurfa.2010.08.011
A series of polymers including polyvinyl alcohol (PVA), polyethylene glycol (PEG), and polystyrene (PS) were successfully adsorbed on mesoporous silica with tubular structure by adding silica particles directly into polymer solution during stirring. Presence of polymers on silica was confirmed by thermogravimetric analysis, FTIR spectroscopy and transmission electron microscopic images. Nitrogen sorption measurements were employed to investigate the variation in surface and pore properties after polymer adsorption. BET specific surface area, pore size distribution (PSD), and surface fractal analysis were calculated in traditional BET (Brunauer, Emmett and Teller) method, BJH (Barret, Joyner and Hanlenda), and the thermodynamic method, respectively from the isotherms. We proposed a model for conformation of polymer adsorbed based on such variations, which was further confirmed by transmission electron microscopic results. We found that PVA and PEG with high polarity (due to high content of oxygen atoms both in the chain or hydroxyl groups), could spread their chains into the tubes of molecular sieves except the adsorption outside of the tubes via hydrogen bond, while PS with relatively low polarity could only adsorb randomly on the surface.
Co-reporter:Yiwen Hu, Qihui He, Zheng Zhang, Naidong Ding and Baixing Hu
Chemical Communications 2011 - vol. 47(Issue 44) pp:NaN12196-12196
Publication Date(Web):2011/09/30
DOI:10.1039/C1CC14153H
With stoichiometric H2O2 as oxidant, dibenzothiophene (DBT) is oxidized to its corresponding sulfone with high efficiency, catalyzed by a sub-valence heteronuclear peroxotungstate, [C18H37N(CH3)3]4[H2SeIV3W6O34], under mild biphase conditions and the catalyst shows remarkable selectivity of catalytic oxidation towards DBT, cinnamyl alcohol and quinoline.
