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Table of Content
28 March 2016, Volume 24 Issue 3
    Measurement of thermal conductivity, viscosity and density of ionic liquid [EMIM][DEP]-based nanofluids
    Hua Xie, Zongchang Zhao, Jianhua Zhao, Hongtao Gao
    2016, 24(3):  331-338.  doi:10.1016/j.cjche.2015.11.024
    Abstract ( 2020 )   PDF (2153KB) ( 127 )  
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    This article studied experimentally the effect ofmulti-wall carbon nanotubes(MWCNTs) on the thermo physical properties of ionic liquid-based nanofluids.The nanofluids were composed of ionic liquid, 1-ethyl-3-methylimidazolium diethylphosphate [EMIM][DEP], or its aqueous solution [EMIM][DEP](1)+H2O(2) and MWCNTs without any surfactants.The thermal conductivity, viscosity and density of the nanofluids were measured experimentally.The effects of the mass fraction of MWCNTs, temperature and the mole fraction of water on the thermo physical properties of nanofluids were studied.Results show that the thermal conductivity of nanofluids increaseswithin the range of 1.3%-9.7% compared to their base liquids, and have a well linear dependence on temperature.The viscosity and density of the nanofluids exhibit a remarkable increase compared with those of the base liquids.Finally, the correlation of the effective thermal conductivity and viscosity of the nanofluids was made using the models in the literatures.
    Novel cobalt-free tantalum-doped perovskite BaFe1-yTayO3-δ with high oxygen permeation
    Qing Liao, Yanjie Wang, Yan Chen, Haihui Wang
    2016, 24(3):  339-344.  doi:10.1016/j.cjche.2015.11.003
    Abstract ( 2200 )   PDF (2094KB) ( 53 )  
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    Cobalt-free perovskite-type oxides BaFe1-yTayO3-δ(0≤y≤0.2) were synthesized via a simple solid state reaction. The cubic perovskite structure can be obtained when y is over 0.1.BaFe0.9Ta0.1O3-δ(BFT0.1) membrane shows the highest oxygen permeation flux, which can reach 1.6 ml·min-1·cm-2 at 950℃ under the gradient of air/He.The O2-TPD results reveal that BaFe0.9Ta0.1O3-δ material shows an excellent reversibility and phase structure stability in air.The oxygen permeation flux is limited by the bulk diffusion when the membrane thickness is over 0.8 mm, and it is limited by both the bulk diffusion and the surface exchange when the membrane thickness is below 0.5 mm.Stable oxygen permeation fluxes are obtained during 180 h operation.
    The effect of cation-π interactions in electrolyte/organic nanofiltration systems
    Gang Yang, YuMa, Weihong Xing
    2016, 24(3):  345-352.  doi:10.1016/j.cjche.2015.11.004
    Abstract ( 1883 )   PDF (716KB) ( 79 )  
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    The rejection properties of a nanofiltration organic membrane were investigated using KCl solutions, NaCl solutions, NaCl/benzyl alcohol hybrid solutions and KCl/benzyl alcohol hybrid solutions.The presence of benzyl alcohol(3.7mol·m-3) caused a decrease in electrolyte rejection within the range of 0 to 6%.Themechanismof the decreasewas discussed.The cation-π bondwas assumed to formin the hybrid solution and to further induce the partial dehydration of the cation.The steric and charge density inhibition of the salt activity was strengthened, and the salt rejection was thus decreased.A simulation was performed to evaluate the radius of the cation.
    Novel method for separation and screening of lubricant-degrading microorganisms and bacterial biodegradation
    Yan Jiang, Hui Qi, Xianming Zhang
    2016, 24(3):  353-359.  doi:10.1016/j.cjche.2015.11.001
    Abstract ( 2012 )   PDF (822KB) ( 60 )  
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    With the rapid increase of lubricant consumption, oil contamination becomes more serious.Biotreatment is an important method to remove oil contamination with some advantages.In this study, acclimatized oilcontaminated soil and used lubricating oil were sampled to isolate lubricant-degrading strains by several methods.51 isolates were obtained and 24-well plates were employed to assess bacterial potential in highthroughput screening.The method was noted for the prominence of oil-water two-phase system with saving chemicals, shortening cycles and lessening workloads.In order to decrease inaccuracy, subculture and resting cells were inoculated into mineral salt medium with 200μl oil in well plates for the cultivation at 37℃ for 5 and 7 days, and the biodegradation potential was characterized by the changes of oil film and cell density. With appropriate evaluation by shaking flask tests, 5 isolates were retained for their potentials with the maximum biodegradation from 1500 to 2200 mg·L-1 and identified as Acidovorax citrulli, Pseudomonas balearica, Acinetobacter johnsonii(two isolates with different biodegradation potentials) and Acidovorax avenae using 16S rRNA sequencing analysis.Also, lipase activity was determined using indicator titration and p-nitrophenyl palmitate(p-NPP) methods.The results indicated that only p-NPP was successful to test lipase activity with the range of 1.93-6.29 U·ml-1.Although these five strains could degrade 1000 mg·L-1 lubricating oil in 158-168 h, there existed distinct difference in enzyme activity, which demonstrates that lipase activity could not be used as the criterion to evaluate microbial biodegradation potential for petroleum hydrocarbons.
    Measurements and thermodynamic modeling of liquid-liquid equilibria in ternary system 2-methoxy-2-methylpropane+p-cresol+water
    Liejin Luo, Dong Liu, Libo Li, Yun Chen
    2016, 24(3):  360-364.  doi:10.1016/j.cjche.2015.10.011
    Abstract ( 1676 )   PDF (440KB) ( 94 )  
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    Liquid-liquid equilibrium(LLE) data for the ternary system 2-methoxy-2-methylpropane(methyl tert-butyl ether)+p-cresol+water was measured at atmospheric pressure and temperatures of 298.15 K and 313.15 K. From the distribution coefficients and selectivity, it was found that 2-methoxy-2-methylpropane is an efficient solvent to extract p-cresol from wastewater.The consistency of the experimental tie-line data was verified with the Hand and Bachman equations.These data were also correlated with the non-random two liquid(NRTL) and universal quasi-chemical correlation activity coefficient(UNIQUAC) models to yield binary interaction parameters for p-cresol extraction process evaluation.Both models agreed with experiments very well, yet the NRTL model showed even smaller average deviation than the UNIQUAC model.
    Effect of methylimidazolium-based ionic liquids on vapor-liquid equilibrium behavior of tert-butyl alcohol+water azeotropic mixture at 101.3 kPa
    Zhigang Zhang, Qiang Zhang, Tao Zhang, Qinqin Zhang, Wenxiu Li
    2016, 24(3):  365-372.  doi:10.1016/j.cjche.2015.10.012
    Abstract ( 2313 )   PDF (853KB) ( 113 )  
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    Three ionic liquids(ILs), 1-ethyl-3-methylimidazoliumbromine([EMIM] Br), 1-butyl-3-methylimidazoliumbromine([BMIM] Br), and 1-hexyl-3-methylimidazoliumbromine([HMIM] Br), were used as the solvent for separation of {tert-butyl alcohol(TBA)+water} azeotrope.Vapor-liquid equilibrium(VLE) data for {TBA+water+IL} ternary systems were measured at 101.3 kPa.The results indicate that all the three ILs produce an obvious effect on the VLE behavior of{TBA+water}system and eliminate the azeotropy in the whole concentration range. [EMIM] Br is the best solvent for the separation of {TBA+water} system by extractive distillation among the three ILs.The experimental VLE data for the ternary systems are correlated with the NRTL model equation with good correlations.Explanations are given with activity coefficients of water and TBA, and the experimental VLE-temperature data for {TBA or water+IL} binary systems.
    Solubilities of CO2 in some glycol ethers under high pressure by experimental determination and correlation
    WeiWang, Zhi Yun, Zhigang Tang, Xia Gui
    2016, 24(3):  373-378.  doi:10.1016/j.cjche.2015.08.007
    Abstract ( 2238 )   PDF (667KB) ( 133 )  
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    The binary vapor-liquid equilibrium data of CO2 in diethylene glycol(monomethyl, monoethyl, monobutyl, dimethyl, diethyl, dibutyl) ether were determined from 288.15 to 318.15 K at pressure up to 6 MPa based on the constant-volumemethod.Itwas found by contrast that the ether group in solvents can promote the CO2 absorption, but the hydroxyl group will inhibit the CO2 absorption.Furthermore, the solubilities of CO2 showed an upward trendwith the increasing molecular lengths of absorbents.The experimental data were also correlatedwith a modified Patel-Teja equation of state(PT EOS) combined with the traditional van derWaals one-fluid mixing rules and the results showed a satisfactory agreement between the model and the experimental data.
    Biotechnology and Bioengineering
    Inocula selection in microbial fuel cells based on anodic biofilm abundance of Geobacter sulfurreducens
    Guotao Sun, Diogo de Sacadura Rodrigues, Anders Thygesen, Geoffrey Daniel, Dinesh Fernando, Anne S. Meyer
    2016, 24(3):  379-387.  doi:10.1016/j.cjche.2015.11.002
    Abstract ( 1575 )   PDF (3138KB) ( 66 )  
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    Microbial fuel cells(MFCs) rely on microbial conversion of organic substrates to electricity.The optimal performance depends on the establishment of amicrobial community rich in electrogenic bacteria.Usually thismicrobial community is established from inoculation of the MFC anode chamber with naturally occurring mixed inocula.In this study, the electrochemical performance of MFCs and microbial community evolution were evaluated for three inocula including domestic wastewater(DW), lake sediment(LS) and biogas sludge(BS) with varying substrate loading(Lsub) and external resistance(Rext) on theMFC.The electrogenic bacterium Geobacter sulfurreducens was identified in all inocula and its abundance duringMFC operation was positively linked to the MFC performance.The LS inoculated MFCs showed highest abundance(18%±1%) of G.sulfurreducens, maximum current density [Imax=(690±30) mA·m-2] and coulombic efficiency(CE=29%±1%) with acetate as the substrate.Imax and CE increased to(1780±30) mA·m-2 and 58%±1%, respectively, after decreasing the Rext from 1000Ω to 200Ω, which also correlated to a higher abundance of G.sulfurreducens(21%±0.7%) on the MFC anodic biofilm.The data obtained contribute to understanding the microbial community response to Lsub and Rext for optimizing electricity generation in MFCs.
    Biodiesel synthesis via metal oxides and metal chlorides catalysis from marine alga Melanothamnus afaqhusainii
    Abdul Majeed Khan, Noureen Fatima
    2016, 24(3):  388-393.  doi:10.1016/j.cjche.2015.12.015
    Abstract ( 1756 )   PDF (1703KB) ( 59 )  
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    This research article demonstrates the most comprehensive comparative catalytic study of differentmetal oxides and metal chlorides towards the methanolysis of triglycerides of marine red macroalga Melanothamnus afaqhusainii.CaO was found to be the most reactive metal oxide that yielded 80% biodiesel while ZnCl2 was the most reactive metal chloride that produced 60% biodiesel bymechanical stirring for 6 h at 100-110℃.The overall reactivity order of the catalysts was found to be CaO >MgO >PbO2 >ZnCl2 >TiCl4 >PbO >HgCl2 >ZnO >AlCl3 >SnCl2 >TiO2 whereas, CaCl2, MgCl2, Al2O3, HgO, PbCl2, MnO2, MnCl2, Fe2O3 and FeCl3 were found to be non-reactive for transesterification of triglycerides.In addition, a detailed study of the screening of mobile phases and spraying reagents was conductedwhich showed that petroleumether:chloroform:toluene(7:2:1) is the bestmobile phase, whereas iodine crystals/silica gel is the best visualizing agent for the thin layer chromatography(TLC) examination of biodiesel.Biodiesel productionwas confirmed by comparative TLC examination.It was further supported by the determination of fuel properties of biodiesel, whichwere found to be similar to the standard limits of American Society for Testing and Materials(ASTM).
    Performance evaluation of a modified step-feed anaerobic/anoxic/oxic process for organic and nutrient removal
    A. R. Majdi Nasab, S. M. Soleymani, M. Nosrati, S. M. Mousavi
    2016, 24(3):  394-403.  doi:10.1016/j.cjche.2015.10.010
    Abstract ( 2023 )   PDF (2776KB) ( 86 )  
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    A pilot scale modified step-feed process was improved to increase nutrient(N and P) and organic removal operations frommunicipal wastewater.It combined the step-feed process and amethod named "University of Cape Town(UCT)".The effect of nutrient ratios and inflow distribution ratios were studied.The highest uptake efficiency of 95% for chemical oxygen demand(COD) has been achieved at the inflow distribution ratio of 40/35/25.However, maximum removal efficiency obtained for total nitrogen(TN) and phosphorus at 93% and 78%, respectively.The average mixed liquor suspended solids(MLSS) was 5500 mg·L-1.In addition, convenient values for dissolved oxygen(DO) concentration, and pH were obtained throughout different stages.The proposed system was identified to be an appropriate enhanced biological nutrient removal process for wastewater treatment plants owing to relatively high nutrient removal, sturdy sludge settle ability and COD removal.
    Wheat straw pretreatment with KOH for enhancing biomethane production and fertilizer value in anaerobic digestion
    Muhammad Jaffar, Yunzhi Pang, Hairong Yuan, Dexun Zou, Yanping Liu, Baoning Zhu, Rashid Mustafa Korai, Xiujin Li
    2016, 24(3):  404-409.  doi:10.1016/j.cjche.2015.11.005
    Abstract ( 2327 )   PDF (1404KB) ( 139 )  
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    Wheat strawbiodegradability during anaerobic digestionwas improved by treatment with potassiumhydroxide(KOH) to decrease digestion time and enhance biomethane production and fertility value.KOH concentrations of 1%(K1), 3%(K2), 6%(K3) and 9%(K4) were tested for wheat straw pretreatment at ambient temperaturewith a C:N ratio of 25:1.86% of total solids(TS), 89% of volatile solids(VS) and 22% of lignocellulose, cellulose and hemicellulose(LCH)(22%) were decomposed effectively with the wheat straw pretreated by 6% KOH.Enhanced biogas production and cumulative biomethane yield of 258 ml·(g VS)-1 were obtained increased by 45% and 41% respectively, compared with untreated wheat straw.Pretreated wheat straw digestion also yielded a digestate with higher fertilizer values potassium(138%), calcium(22%) and magnesium(16%).These results show that TS, VS and LCH can be effectively removed from wheat straw pretreated with KOH, improving biodegradability biomethane production and fertilizer value.
    Preparation of dendritic bismuth filmelectrodes and their application for detection of trace Pb(Ⅱ) and Cd(Ⅱ)
    Huizhu Zhou, Huanhuan Hou, Lei Dai, Yuehua Li, Jing Zhu, LingWang
    2016, 24(3):  410-414.  doi:10.1016/j.cjche.2015.08.012
    Abstract ( 1763 )   PDF (1436KB) ( 64 )  
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    In this paper, dendritic Bi film electrodes with porous structure had successfully been prepared on glassy carbon electrode using a constant current electrolysis method based on hydrogen bubble dynamic templates.The electrode prepared using a large applied current density showed an increased internal electroactive area and a significantly improved electrochemical performance.The analytical utility of the prepared dendritic Bi film electrodes for the determination of Pb(Ⅱ) and Cd(Ⅱ) in the range of 5-50μg·L-1 were presented in combination with squarewave stripping voltammetry inmodel solution.Comparedwith non-porous Bi film electrode, the dendritic Bi film electrode exhibited higher sensitivity and lower detection limit.The prepared Bi film electrode with dendritic structure was also successfully applied to real water sample analysis.
    The structure, tensile properties and water resistance of hydrolyzed feather keratin-based bioplastics
    Yao Dou, Buning Zhang, Ming He, Guoqiang Yin, Yingde Cui
    2016, 24(3):  415-420.  doi:10.1016/j.cjche.2015.11.007
    Abstract ( 2316 )   PDF (1091KB) ( 197 )  
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    Feather, as a by-product of the poultry industry, has long been treated as a solid waste, which causes environmental and economic problems.In this work, the hydrolyzed feather keratin(HFK) was extracted fromthe chicken feather using a cost-effectivemethod of alkali-extraction and acid-precipitation by applying urea and sodium sulfide.The aim was development and characterization of the eco-friendly films based on the HFK with variable glycerol contents by a thermoplastic process.The thermal analysis showed that high temperature and high pressure improved the compatibility between the glycerol and the HFK molecules.Also it was shown that the addition of water is necessary in the hot-pressing process of films.The FT-IR analysis indicated that the formation of the new hydrogen bonds between HFK and glycerol.By increasing the glycerol content, the film tensile strength(σb) decreases from10.5 MPa to 5.7 MPa and the solubility increases from15.3% to 20.9%, while the elongation at break(εb) achieves themaximumvalue of 63.8% for the film with 35% glycerol.The swellingwas just below 16.9% at 25℃ for 24 h, suggesting a good stability of the films in water.The water vapor permeability(WVP) varied between 3.02×10-10 g·m-2·s-1·Pa-1 and 4.11×10-10 g·m-2·s-1·Pa-1 for the films with 20% and 40% glycerol, respectively.The HFK film was uniform, translucent and tough, which could be used in packaging and agricultural field.
    Controlled release and enhanced antibacterial activity of salicylic acid by hydrogen bonding with chitosan
    Zujin Yang, Yanxiong Fang, Hongbing Ji
    2016, 24(3):  421-426.  doi:10.1016/j.cjche.2015.08.008
    Abstract ( 1998 )   PDF (1387KB) ( 66 )  
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    Microcapsules of salicylic acid(SA) with chitosan were prepared by spray drying method.Various analytical methods were used to characterize the nature of microcapsules.Fourier-transform infrared spectroscopy(FTIR) confirmed the presence of intermolecular interactions between chitosan and SA.Particle size analysis showed that the average size of microcapsules ranged from 2 to 20μm.Scanning electron microscopy(SEM) studies indicated that the microspheres were spherical and had a relatively smooth surface.Microbiological assay of antibacterial activity for SA and its microcapsules was measured using different bacterial strains.It was found that the antibacterial activity of SA was improved after the formation of microcapsules.The in vitro release profile showed that the microcapsules could control SA release from 1 h to 4 h.Kinetic studies revealed that the release pattern follows Korsmeyer-Peppas mechanism.Enhanced antibacterial activity of the SA microcapsules was attributed to the synergistic effects of intermolecular hydrogen-bonding interactions N-H…O and O-H…O_C between SA and chitosan.It was also confirmed by quantum chemical calculation.
    Influence of synthesis parameters on the properties of LiFePO4/C cathode material
    Zhengwei Xiao, Yingjie Zhang, Guorong Hu
    2016, 24(3):  427-432.  doi:10.1016/j.cjche.2015.03.013
    Abstract ( 2330 )   PDF (4749KB) ( 111 )  
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    The influence of sintering temperature, carbon content and dispersive agent in ball-milling was investigated on the properties of LiFePO4/C prepared using Fe2O3, NH4H2PO4, Li2CO3 and glucose via solid state reaction.X-ray powder diffraction, scanning electron microscopy and charge-discharge testwere applied to the characterization of the LiFePO4/C samples synthesized under different conditions.Sintering temperature affects the crystallite/particle size and degree of crystallinity of LiFePO4, formationof Fe2P and maintenance of carbon in LiFePO4/C.Carbonmaintenance is favored by lowsintering temperature, and 700℃ is optimumfor synthesis of LiFePO4/C with superior electrochemical performance.A higher carbon content in the range of 4.48%-11.03% results in a better rate capability for LiFePO4/C.The dispersive agent used in ball-milling impacts the existent state of carbon in the final product which subsequently determines its charge-discharge behavior.The sample prepared at 700℃ by using acetone as the dispersive agent in ball-milling exhibits an excellent rate capability and capacity retention without any fade at 0.1C, 1C and 2C, with corresponding average discharge capacities of 153.8, 128.3 and 121.0 mA·h·g-1, respectively, in the first 50 cycles.