Time filter

Source Type

Qin Y.,Chemical Engineering Research Center | Qin Y.,Tianjin University of Technology | Li B.,Chemical Engineering Research Center | Li B.,Tianjin University of Technology | Wang S.,Chemical Engineering Research Center
Industrial and Engineering Chemistry Research | Year: 2012

Plastic heat exchangers have attracted more and more attention because of their superior resistance to chemicals and fouling.However, the thermal conductivity of plastic materials is much lower than that of metal, which limits the wider application of plastic heat exchangers. In this study, polypropylene-based hollow fibers as a heat-conducting medium for heat exchangers was developed by melt-mixing polypropylene with graphite particles and maleated polypropylene (PP-g-MA). Results show that the addition of graphite fairly improved the crystalline, thermal stability and conductivity of the polypropylene resin and further improved the heat transfer efficiency of polypropylene-based hollow fiber heat exchangers. The overall heat transfer coefficient of 15.0 wt % graphite modified polypropylene hollow fiber heat exchangers reached 1228.7 W/(m2 3 K), which is 5 times higher than that of pure PP-based hollow fiber heat exchangers, and the overall conductance per unit volume reached 1.1 × 10 6 W/(m 3 · K). Further, the heat transfer efficiency increases fairly with the increase of the fluid flow rate, especially with the flow rate of the tubeside. The optimized operation mode is that the hot water flows on the tube-side and the cold water flows on the shell-side. © 2011 American Chemical Society.

Yu Q.,Northwest University, China | Yu Q.,Chemical Engineering Research Center | Yu Q.,The Clean Tech Center | Ma X.,Northwest University, China | And 5 more authors.
Fluid Phase Equilibria | Year: 2012

The solubilities of suberic acid in methanol, ethanol, 1-propanol, 2-propanol, propanone, water, ethyl acetate and tetrahydrofuran were determined at temperatures between 283. K and 340. K. The experimental data can be well correlated by Apelblat model. The dissolution enthalpy and entropy of suberic acid were predicted from the solubility data using van't Hoff equation. © 2012.

Han L.-F.,East China University of Science and Technology | Han L.-F.,Chemical Engineering Research Center | Xu Z.-L.,East China University of Science and Technology | Xu Z.-L.,Chemical Engineering Research Center | And 3 more authors.
Journal of Membrane Science | Year: 2011

Al2O3, Al2O3-SiO2 and Al2O3-kaolin hollow fiber precursors were prepared by a wet-spinning method using polyethersulfone (PES), Al2O3, SiO2 and kaolin. The hollow fiber membranes were obtained after a preheating and sintering combining process. These inorganic hollow fiber membranes had been characterized by SEM, XRD, porosity, density, mechanical property, permeation property and the mean/maximum pore size as well as pore size distribution, to investigate the effects of SiO2 and kaolin on α-Al2O3 hollow fiber membranes. The morphology of precursors depended on the particle contents and PES concentrations in the dispersion, and the final structure of sintered membranes were controlled by the precursors. XRD results showed that Al2O3 remained as α-Al2O3 before and after being sintered while SiO2 changed from tridymite to cristobalite from ambient temperature to 1450°C, and at higher temperature it would react with Al2O3 to produce the stoichiometric 3:2 mullite (3Al2O3·2SiO2, or Al6Si2O13) by solid state reaction. The effect of SiO2 and kaolin on the membrane properties depended on both the ratio of Al2O3:SiO2/kaolin and the sintering temperature. Moreover, when sintering temperature was 1600°C, Al2O3-kaolin-5 (Al2O3:kaolin=1:1) achieved a mean pore size of about 0.5μm. © 2011 Elsevier B.V.

Sun C.,Chemical Engineering Research Center | Xie L.,Chemical Engineering Research Center | Li X.,Chemical Engineering Research Center | Sun L.,Tianjin MOTIMO Membrane Technology Co. | Dai H.,Tianjin MOTIMO Membrane Technology Co.
Desalination | Year: 2015

Performance of different pretreatment systems with ultrafiltration (UF) prior to reverse osmosis (RO) for desalting seawater was assessed in this paper. The pilot trial was operated on seawater from Bohai Bay in Tianjin using polyvinylidene fluoride (PVDF) hollow fiber UF membrane. During these experiments, membrane specific flux (SF) was calculated to evaluate the performance of UF. Results of the research showed that in a chemical enhanced backwash (CEB) period, the combination of UF with FeCl3 flocculation pretreatment was helpful in controlling the decrease of SF during the operation. Besides, the result also showed that FeCl3 flocculation/dual-stage sand filtration/UF performed effectively in terms of the stable of SF in a CEB period than FeCl3 flocculation/UF alone. In addition, water analysis was regularly performed to quantify pollutants in the effluents of different hybrid processes. According to the experiment, UF can provide product water with consistently low turbidity (0.07-0.12NTU) and low silt density index (SDI15 less than 2) levels regardless of seawater quality. Sand filtration showed good performance for turbidity removal (less than 0.5NTU in effluent), but limited effect on SDI removal (not below 4). Total organic carbon (TOC) removal up to 28% was obtained in FeCl3 flocculation/dual-stage sand filtration/UF hybrid system. © 2015 Elsevier B.V.

Li Q.,East China University of Science and Technology | Li Q.,Chemical Engineering Research Center | Xu Z.-L.,East China University of Science and Technology | Xu Z.-L.,Chemical Engineering Research Center | Liu M.,Chemical Engineering Research Center
Polymers for Advanced Technologies | Year: 2011

Using the mixture of triethyl phosphate (TEP) and N,N-dimethylacetamide (DMAc) as solvent, PVDF microporous membranes with highly hydrophobic surface were prepared by a modified NIPS method with a dual coagulation process. The effects of the exposure time on these membranes before being immersed into the coagulation bath and the composition in the coagulation bath on precipitation rate, membrane morphology, membrane hydrophobicity, membrane mechanical property, and membrane performance were studied. The morphologies and hydrophobicities of PVDF microporous membranes were investigated by scanning electron microscopy (SEM) and contact angle (CA) measurement. The precipitation processes were observed by light transmittance measurement. The pore size distribution was determined by liquid permeation technique. PVDF microporous membrane obtained by passing evaporation period of 60min before being immersed into the water bath showed a high water CA of 122.1°. Using ethanol (EtOH) as coagulation bath, the water CAs of the top surface and bottom surface of the membrane increased to 125.9 and 132.6°, respectively. To further improve PVDF membrane hydrophobicity, a dual coagulation process was used and the mixed solvent (TEP-DMAc) was added into the first coagulation bath for 30sec. Increase in the TEP-DMAc content led to the change in the morphology type of the membrane, that is, from an asymmetric structure with a dense top surface to a symmetric structure with a skinless top surface, and the pore size distribution widened greatly. By increasing the mass ratio of TEP to DMAc, the denseness of the membrane surface decreased significantly. Adding 60wt% of TEP-DMAc to the first coagulation bath and the mass ratio of TEP to DMAc was 60:40, the CA reached to a maximum as high as 136.6°, and PVDF microporous membrane showed a high porosity of 80% and an excellent mechanical property of 3.14MPa tensile strength and 61.79% elongation ratio. © 2009 John Wiley & Sons, Ltd.

Li Q.,East China University of Science and Technology | Li Q.,Chemical Engineering Research Center | Xu Z.-L.,East China University of Science and Technology | Xu Z.-L.,Chemical Engineering Research Center | Yu L.-Y.,Chemical Engineering Research Center
Journal of Applied Polymer Science | Year: 2010

Polyvinylidene fluoride (PVDF) microporous flat membranes were cast with different kinds of PVDFs and four mixed solvents [trimethyl phosphate (TMP) - N,N - dimethylacetamide (DMAc), triethyl phosphate (TEP) - DMAc, tricresyl phosphate (TCP) - DMAc, and tri - n - butyl phosphate (TBP) - DMAC]. The effects of different commercial PVDFs (Solef® 1015, FR 904, Kynar 761, Kynar 741, Kynar 2801) on membrane morphologies and membrane performances of PVDF/TEP - DMAc/PEG200 system were investigated. The membrane morphologies were examined by scanning electron microscopy (SEM). The membrane performances in terms of pure water flux, rejection, porosity, and mean pore radius were measured. The membrane had the high flux of 143.0 ± 0.9 L m - 2 h - 1 when the content of TMP in the TMP - DMAc mixed solvent reached 60 wt %, which was 2.89 times that of the membrane cast with DMAc as single solvent and was 3.36 times that of the membrane cast with TMP as single solvent. Using mixed solvent with different solvent solubility parameters, different morphologies of PVDF microporous membranes were obtained. TMP - DMAc mixed solvent and TEP - DMAc mixed solvent indicated the stronger solvent power to PVDF due to the lower solubility parameter difference of 1.45 MPa1/2 and the prepared membranes showed the faster precipitation rate and the higher flux. The less macrovoids of the membrane prepared with TEP (60 wt %) - DMAc (40 wt %) as mixed solvent contributed to the higher elongation ratio of 96.61% ± 0.41%. Therefore, using TEP(60 wt %) - DMAc (40 wt %) as mixed solvent, the casting solution had the better solvent power to PVDF,andthemembranepossessedtheexcellentmechanical property. The microporous membranes prepared from casting solutions with different commercial PVDFs exhibited similar morphology, but the water flux increased with the increment of polymer solution viscosity. © 2009 Wiley Periodicals, Inc.

Cong H.,Chemical Engineering Research Center
Sheng wu yi xue gong cheng xue za zhi = Journal of biomedical engineering = Shengwu yixue gongchengxue zazhi | Year: 2010

A hydrophobic low-density lipoprotein cholesterol (LDL-C) adsorbent was synthesized with lauric acid and chitosan. The condition for adsorption was obtained by investigating the influence of adsorbent amount and adsorption time. The results of adsorption in vitro showed that the average adsorption rates for total cholesterol (TC), LDL-C, high-density lipoprotein cholesterol (HDL-C) and total protein (TP) were 47.7%, 84.7%, 18.1% and 5.9% respectively. The adsorbent possesses good selectivity in removing LDL-C.

Cong H.,Chemical Engineering Research Center
Sheng wu yi xue gong cheng xue za zhi = Journal of biomedical engineering = Shengwu yixue gongchengxue zazhi | Year: 2010

The selective removal of low density lipoprotein (LDL) and fibrinogen (Fib) by degraded carrageenan was studied by the present authors. Degraded carrageenan was prepared by acid with carrageenan as the main material. The effects of acid conditions on the molecular weight were investigated, and the proper reaction conditions were ascertained. The results of infrared spectrometry indicated that the degraded carrageenan is a heparin-like polysaccharide. Then the selective removal of LDL/Fibrinogen by degraded carrageenan was studied. When molecular weight was about 10,000, pH was 5.10 and the concentration of degraded carrageenan was 800 mg/L, the average reduction percentages were 60.0% for total cholesterol(TC), 79.4% for LDL and very low-density lipoprotein (VLDL), and 93.8% for fibrinogen. There were no significant changes with relation to the level of high-density lipoprotein (HDL) and total protein (TP). So, degraded carrageenan was shown to be of good selectivity on plasma LDL/Fibrinogen apheresis.

Hu Z.,Chemical Engineering Research Center | Zhang X.,Chemical Engineering Research Center | Zhang D.,Chemical Engineering Research Center | Wang J.-X.,Chemical Engineering Research Center
Water, Air, and Soil Pollution | Year: 2012

A directly amine-functionalized mesoporous silica (AMS) was prepared via an anionic surfactant-mediated synthesis method and used as adsorbents for deep removal of Cu 2+ ions from aqueous solution at room temperature. The synthesized AMS had been characterized by X-ray diffraction, nitrogen physisorption measurement, and thermogravimetric analysis. The amine groups prefer to position to the surface of AMS material due to the S -N +~I - mechanism. Copper adsorption process had been studied from both kinetic and equilibrium points of view for AMS material. Experiments proved that the aqueous Cu 2+ adsorption rates were fast and adsorption capacity was about 53.3 mg/g. © Springer Science+Business Media B.V. 2011.

Feng F.,East China University of Science and Technology | Feng F.,Chemical Engineering Research Center | Xu Z.,East China University of Science and Technology | Xu Z.,Chemical Engineering Research Center | And 3 more authors.
Journal of Environmental Sciences | Year: 2010

The performance of combined Fenton oxidation and membrane bioreactor (MBR) process for the advanced treatment of an effluent from an integrated dyeing wastewater treatment plant was evaluated. The experimental results revealed that under the optimum Fenton oxidation conditions (initial pH 5, H2O2 dosage 17 mmol/L, and Fe2+ 1.7 mmol/L) the average total organic carbon (TOC) and color removal ratios were 39.3% and 69.5% after 35 min of reaction, respectively. Results from Zahn-Wallens Test also represented that Fenton process was effective to enhance the biodegradability of the test wastewater. As for the further purification of MBR process, TOC removal capacity was examined at different hydraulic retention times (HRT) of 10, 18 and 25 hr. Under the optimum HRT of 18 hr, the average TOC concentration and color of the final MBR effluent were 16.8 mg/L and 2 dilution time, respectively. The sludge yield coefficient was 0.13 g MLSS/g TOC and TOC degradation rate was 0.078 kg TOC/(m3·day). The final effluent of MBR can meet the reuse criteria of urban recycling water - water quality standard for miscellaneous water consumption GBT18920-2002. © 2010 The Research Centre for Eco-Environmental Sciences, Chinese Academy of Sciences.

Loading Chemical Engineering Research Center collaborators
Loading Chemical Engineering Research Center collaborators