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ABSTRACT: Hair samples collected from e-waste recycling workers (n=23 males, n=4 females) were analyzed to assess occupational exposures to polybrominated diphenyl ethers (PBDEs) and polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) at a large e-waste recycling facility in Taizhou, eastern China. Hair samples from a reference population composed of residents of Shanghai (n=11) were analyzed for comparison. The mean concentration of ∑PBDEs (range, 22.8-1020 ng/g dw; mean, 157 ng/g dw) found in hair samples from e-waste recycling workers was approximately 3 times higher than the mean determined for the reference samples. The congener profiles of PBDEs in hair from e-waste recycling workers were dominated by BDE 209, whereas the profiles in the reference-population samples showed comparable levels of BDE 47 and BDE 209. Total PCDD/F concentrations in hair from e-waste workers (range, 126-5820 pg/g dw; mean, 1670 pg/g dw) were approximately 18-fold greater than the concentrations measured in hair from the reference population. Concentrations of PCDFs were greater than concentrations of PCDDs, in all of the hair samples analyzed (samples from e-waste and non-e-waste sites). Tetrachlorodibenzofurans (TCDFs) were the major homologues in hair samples. Overall, e-waste recycling workers had elevated concentrations of both PBDEs and PCDD/Fs, indicating that they are exposed to high levels of multiple persistent organic pollutants.
Journal of hazardous materials 02/2011; 186(2-3):1966-71. · 4.14 Impact Factor
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ABSTRACT: The rational design of polymer−inorganic nanocomposite membranes relies heavily on the precise insight and elaborate control of the interface. Presently, the direct exploration of the hierarchical structure of nanocomposite membranes still remains elusive. In the present study, we propose a facile and generic methodology to quantitatively probe the interfacial structure by complementary positron annihilation lifetime spectroscopy (PALS) and molecular dynamics simulation (MDS) techniques. MDS is used to acquire the molecular level information such as the polymer−inorganic interface interaction energy, chain mobility within the nanocomposite membranes, whereas PALS is used to acquire the free volume characteristics of the nanocomposite membranes. As proof-of-principle, we choose anisotropic inorganic nanotube embedded rubbery polymer membrane as a model, which generates the interface between soft polymer and rigid inorganic. PALS reveals that incorporation of titanate nanotubes (TNTs) narrows the free volume pore radius distribution of the membranes. MDS indicates that the segmental chain mobility in the vicinity of the polymer−inorganic interface is substantially restrained, which creates numerous nanosized voids for molecular transport, and dramatically enhances the fractional free volume (FFV) of the membranes. Quite interestingly, it was found that the rubbery membranes can also exhibit simultaneously increased permeability and membrane selectivity, and this unusual phenomenon was tentatively elucidated by relating the separation properties to the free volume characteristics of the membranes.
11/2010;
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ABSTRACT: The formation and release of polybrominated dibenzo-p-dioxins and dibenzofurans (PBDD/Fs) from the incineration of electronic wastes (e-waste) that contain brominated flame retardants (BFRs) are a concern. However, studies on the determination of PBDD/Fs in environmental samples collected from e-waste recycling facilities are scarce. In this study, 11 2,3,7,8-substituted PBDD/Fs and 10 polybrominated diphenyl ether (PBDE) congeners were determined in electronic shredder waste, workshop-floor dust soil, and leaves (of plants on the grounds of the facility) from a large-scale e-waste recycling facility and in surface soil from a chemical-industrial complex (comprising a coke-oven plant, a coal-fired power plant, and a chlor-alkali plant) as well as agricultural areas in eastern China. Total PBDD/F concentrations in environmental samples were in the range of 113-818 pg/g dry wt (dw) for leaves, 392-18500 pg/g dw for electronic shredder residues, 716-800000 pg/g dw for soil samples, and 89600-pg/g dw for workshop-floor dust from the e-waste recycling facility and in a range from nondetect (ND) to 427 pg/g dw in soil from the chemical-industrial complex. The highest mean concentrations of total PBDD/Fs were found in soil samples and workshop-floor dust from the e-waste recycling facility. The dioxin-like toxic equivalent (measured as TEQ) concentrations of PBDD/Fs were greater than the TEQs of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) reported in our previous study for the same set of samples. The concentrations of PBDFs were several orders of magnitude higher than the concentrations of PBDDs in samples from the e-waste facility or from soil from the chemical-industrial complex. A significant correlation was found between the concentrations of sigmaPBDD/Fs and sigmaPBDEs (r = 0.769, p < 0.01) and between sigmaPBDD/Fs and the previously reported sigmaPCDD/F concentrations (r = 0.805, p < 0.01). The estimated daily human intakes of TEQs contributed by PBDD/Fs via soil/dust ingestion and dermal exposures in e-waste recycling facilities were higher than the intakes of TEQs contributed by PCDD/ Fs, calculated in our previous study.
Environmental Science and Technology 10/2009; 43(19):7350-6. · 5.23 Impact Factor
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ABSTRACT: Polybrominated diphenyl ethers (PBDEs) have recently been shown to be on the increase in the environment and in human milk. The most commonly found PBDE congener in human milk is 2,2',4,4',5-penta BDE (BDE-99). The aim of the present study was to investigate the neurotoxic effects of BDE-99 (2 mg kg(-1)d(-1)) administration, from gestational day 6 to postnatal day (PND) 21, on neurobehavioural development and redox responses in offspring. Neurobehavioural development analysis revealed a delayed appearance of cliff drop and negative geotaxis reflexes in the exposed group. Furthermore, developmental exposure to BDE-99 also affected learning and memory functions during adolescence. On PND 37, the activity of superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) was reduced, while increases in hydrogen peroxide, lipid peroxidation, nitric oxide and electron spin resonance signal intensities were observed in the hippocampus of BDE-99-treated animals. However, the activity of SOD and GSH-Px in the cerebellum and cerebral cortex was not significantly different between treated and control animals. The present study demonstrated that developmental BDE-99 exposure causes oxidative stress in the hippocampus of offspring by altering the activity of different antioxidant enzymes and producing free radicals. We demonstrated adverse effects of developmental exposure to BDE-99 associated with tissue concentrations very close to the current human body burden of this persistent and bioaccumulative compound.
Chemosphere 03/2009; 75(7):963-8. · 3.21 Impact Factor
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ABSTRACT: Chlorinated polycyclic aromatic hydrocarbons (CIPAHs) are a class of halogenated contaminants found in the urban atmosphere; they have toxic potential similar to that of dioxins. Information on the sources of CIPAHs is limited. In this study, concentrations of 20 CIPAHs and 16 parent PAHs were measured in electronic wastes, workshop-floor dust, vegetation, and surface soil collected from the vicinity of an electronic waste (e-waste) recycling facility and in surface soil from a chemical industrial complex (comprising a coke-oven plant, a coal-fired power plant, and a chlor-alkali plant), and agricultural areas in central and eastern China. High concentrations of SigmaCIPAHs were found in floor dust (mean, 103 ng/g dry wt), followed in order of decreasing concentration by leaves (87.5 ng/g drywt), electronic shredder waste (59.1 ng/g dry wt), and soil (26.8 ng/g dry wt) from an e-waste recycling facility in Taizhou. The mean concentration of SigmaCIPAHs in soil from the chemical industrial complex (88 ng/g dry wt) was approximately 3-fold higher than the concentration in soil from e-waste recycling facilities. The soils from e-waste sites and industrial areas contained mean concentrations of SigmaCIPAHs 2 to 3 orders of magnitude higher than the concentrations in agricultural soils (ND-0.76 ng/g), suggesting that e-waste recycling and chlorine-chemical industries are potential emission sources of CIPAHs. The profiles of CIPAHs in soil and dust were similar to a profile that has been reported previously for fly ash from municipal solid waste incinerators (6-CIBaP was the predominant compound), but the profiles in vegetation and electronic shredder waste were different from those found in fly ash. Concentrations of 16 parent PAHs were high (150-49,700 ng/g) in samples collected from the e-waste recycling facility. Significant correlation between SigmaCIPAH and SigmaPAH concentrations suggests that direct chlorination of parent PAHs is the major pathway of formation of CIPAHs during e-waste recycling operations. Dioxin-like toxic equivalency quotients (TEQs) for CIPAHs and PAHs in samples were calculated on the basis of relative potencies reported for CIPAHs and PAHs. The highest mean TEQ concentrations of CIPAHs (518 pg-TEQ/g) were found for workshop-floor dust, followed by leaves (361 pg-TEQ/g), electronic shredder waste (308 pg-TEQ/g), soil from the chemical industrial complex (146 pg-TEQ/g), and soil from the sites of the e-waste recycling facility (92.3 pg-TEQ/g). With one exception, the floor dust samples, the TEQ concentrations of CIPAHs found in multiple environmental matrices in this study were higher than the TEQ concentrations of PCDD/Fs in the same samples reported in our earlier study.
Environmental Science and Technology 03/2009; 43(3):643-9. · 5.23 Impact Factor
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ABSTRACT: Polychlorinated biphenyls and methylmercury are two of the most ubiquitous environmental contaminants in Guizhou province. Rice is eaten with almost every meal and provides more calories than any single food in Guizhou province. The estimated tolerable daily intake of total mercury, MeHg, Se and PCBs from Guizhou contaminated rice by Chinese people showed that MeHg and/or PCBs exceeded the corresponding limits. The aim of this study was to characterize the effects of exposure to environmental contaminated rice on neurobehavioral development and neurobiological disruptions in mice. Animals were treated from postnatal day (PND) 22 to 91. At PND 26-91 days of age, mice were tested for neurobehavioural development and neurochemical level changes. We showed that dietary exposure to environmentally contaminated rice gave rise to different changes in antioxidants. Reduced superoxide dismutase (SOD) activity and excess increased nitric oxide (NO) indicated aggravation of oxidative status after long-term dietary intake of Hg and PCBs. Neurobehavioral derangement in the central nervous system and significant delay in the Morris water maze test response on PND 91 are correlated with the increased of c-fos/c-jun expression levels in the cerebral cortex. These results suggest that MeHg neurotoxicity might be a greater hazard than that associated with PCB, but PCB may augment the neurobehavioral deficits caused by increased levels of mercury exposure. The simultaneous intake of selenium might have a protective effect on Hg accumulation in the body, and vitamin C might protect mice against the toxic effects of PCBs. However, the protective role of Se and vitamin C is very limited for multiple-agent pollution. Immediately early genes in the brain response to contaminated rice might be dependent on interaction among NO, NO synthase (NOS), SOD and reduced glutathione (GSH). We should be alert to mental health problems in human beings when any kind of Hg- and PCB-polluted food is consumed.
Environment international 02/2009; 35(3):619-25. · 4.79 Impact Factor
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ABSTRACT: Environmental pollution arising from electronic waste (e-waste) disposal and recycling has received considerable attention in recent years. Treatment, at low temperatures, of e-wastes that contain polyvinylchloride and related polymers can release polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs). Although several studies have reported trace metals and polybrominated diphenyl ethers (PBDEs) released from e-waste recycling operations, environmental contamination and human exposure to PCDD/Fs from e-waste recycling operations are less well understood. In this study, electronic shredder waste and dust from e-waste facilities, and leaves and surface soil collected in the vicinity of a large scale e-waste recycling facility in Taizhou, Eastern China, were analyzed for total PCDD/ Fs including 2,3,7,8-substituted congeners. We also determined PCDD/Fs in surface agricultural soils from several provinces in China for comparison with soils from e-waste facilities. Concentrations of total PCDD/Fs were high in all of the matrices analyzed and ranged from 30.9 to 11400 pg/g for shredder waste, 3460 to 9820 pg/g dry weight for leaves, 2560 to 148000 pg/g dry weight for workshop-floor dust, and 854 to 10200 pg/g dry weight for soils. We also analyzed surface soils from a chemical industrial complex (a coke-oven plant, a coal-fired power plant, and a chlor-alkali plant) in Shanghai. Concentrations of total PCDD/Fs in surface soil (44.5-531 pg/g dry wt) from the chemical industrial complex were lower than the concentrations found in soils from e-waste recycling plants, but higher than the concentrations found in agricultural soils. Agricultural soils from six cities in China contained low levels (3.44-33.8 pg/g dry wt) of total PCDD/Fs. Profiles of dioxin toxic equivalents (TEQs) of 2,3,7,8-PCDD/Fs in soils from e-waste facilities in Taizhou differed from the profiles found in agricultural soils. The estimated daily intakes of TEQs of PCDD/ Fs via soil/dust ingestion and dermal exposure (2.3 and 0.363 pg TEQ/kg bw/day for children and adults, respectively) were 2 orders of magnitude higher in people at e-waste recycling facilities than in people at the chemical industrial site (0.021 and 0.0053 pg TEQ/kg bw/day for children and adults, respectively), implying greater health risk for humans from dioxin exposures at e-waste recycling facilities. The calculated TEQ exposures for e-waste workers from dust and soil ingestion alone were 2-3 orders of magnitude greater than the exposures from soils in reference locations.
Environmental Science and Technology 12/2008; 42(22):8252-9. · 5.23 Impact Factor
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ABSTRACT: As one of China's great metropolises, Shanghai is suffering from the impact of manufacture and the use of chemical industrial products, and it faces serious pollution from polychlorinated biphenyls (PCBs). Therefore, in this study, in order to assess the seasonal and spatial character of contamination from chemical industrial zones, the concentrations of PCBs have been measured in various environmental media, including soil, leaves, and atmospheric particulate samples collected in a chemical industrial zone of Shanghai and compared with samples from presumably unpolluted sites of rural areas. In soils, the PCB concentrations ranged from 0.5 ng g(-1) (unpolluted site) to 586.85 ng g(-1) (chlor-alkali industry site). The concentrations of PCBs in evergreen leaves ranged from 0.3 ng g(-1) to 32.46 ng g(-1), and more chlorinated biphenyls congeners, such as penta-biphenyls and hexa-biphenyls, were the dominant contributors in winter and spring. Seasonal differences and the constitution patterns of congeners might be affected by the temperature and industrial activities. The PCB concentrations in the leaves of deciduous trees increase over time as the leaves grow. The PCB concentration in atmospheric particulates was in the range of 9.22-14.15 x 10(3)pg m(-3), which might be the result of influence from climate and industrial activities. The relativity of PCB contents among the environmental media was discussed. The results in this paper provide an important profile of the current contamination status of a key chemical industrial zone in China.
Environmental Geochemistry and Health 01/2008; 29(6):503-11. · 1.62 Impact Factor
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ABSTRACT: In order to gain comprehensive understanding of status, properties and sources of PCBs pollution at an industrial area in Shanghai, PM10 were collected during the period November 2004-September 2005. The results showed that the mean value of total PCBs in the industrial area was 2,017.22 pg m(-3). Three dioxin-like PCB congeners had a mean value of TEQ of 0.24 pg-TEQ m(-3). The concentrations of PCBs at all sites were higher in colder months than in warmer months. SigmaPCB concentrations were correlated positively with SO2, NO2 and OCPs, while negatively with polycyclic aromatic hydrocarbons (PAHs), ambient temperature, rainfall and wind speed. It could be concluded that the area had been contaminated by PCBs from a local source.
Bulletin of Environmental Contamination and Toxicology 11/2007; 79(4):448-53. · 1.02 Impact Factor
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ABSTRACT: In order to study the distributions characteristics, sources and relationship of PAHs in PM10- phoenix tree leaves-soil system of a coking & chemical factory in Shanghai, the samples of PM10, phoenix tree leaves and soil around the factory were collected for a year. The concentration of PAHs were analyzed according to the USEPA method 8 000 series. The results showed that the average concentration of PAHs in PM10, phoenix tree leaves and soil were 101.11 ng/m3, 79.45 ng/g and 121.53 microg/g, respectively. Particulate phase (PM10) contained mainly carcinogenic and mutagenic PAHs, among which BaA, BghiP, Flu and BaP were found at significant concentrations. In phoenix tree leaves, Nap,Chy, BaP and BghiP presented a higher level of concentration. In soil, 3 and 4-ring PAHs presented a higher level. PAHs concentrations of phoenix tree leaves were very lower in May. Only Ace (0.16 ng/g) and Pyr (0.63 ng/g) were detected. In July and August the concentrations (39.19 ng/g and 150.94 ng/g, respectively) were uplifted significantly. It could be concluded PAHs was from petroleum and coal-fired compound source. There were very strong positive relationships of 16 PAHs level among phoenix tree leaves, soil and PM10 (p < 0.01).
Huan jing ke xue= Huanjing kexue / [bian ji, Zhongguo ke xue yuan huan jing ke xue wei yuan hui "Huan jing ke xue" bian ji wei yuan hui.] 08/2007; 28(8):1802-5.
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ABSTRACT: Polycyclic aromatic hydrocarbons (PAHs) are ubiquitous pollutants in the urban atmosphere. In particular, atmospheric pollution
has increasingly become severe in China due to its rapid urbanization and industrialization. In recent years, a few studies
have presented information about POPs (such as PAHs, PCBs, OCPs) in aerosols at a molecular level in a limited number of cities
such as Beijing, Qingdao and Guangzhou, as well as Hong Kong. Whereas, these cities are located in northern and southern China,
respectively, where characteristics of atmospheric pollution might be different from those in the eastern cities, such as
Shanghai. Atmospheric particle pollution is a persistent problem in Shanghai, a typical metropolis of China, which has several
huge industrial regions. In order to gain a comprehensive understanding of the present state, properties and sources of PAHs
pollution in Shanghai, PM10 samples were collected at Coal-Fired Power Plant (CFP), Chlor-Alkali Chemical factory (CAC) and Coking and Chemical factory
(CCF) in an industrial area, during the period, November 2004–September 2005. The concentrations of 16PAHs were analyzed
using the HPLC with UV visible detector. The results showed that the mean value of total PAHs in the industrial area was 64.85ng
m−3; 3-ring PAHs were found at low levels, while 4-, 5- and 6-ring PAHs were found at high levels. The levels of BaP were 3.07
and 7.16ng m−3 at Chlor-Alkali Chemistry Factory and Coking and Chemistry Factory sites, respectively. PAHs levels exhibited distinct seasonal
variation, with the highest level in autumn and the lowest in summer. The major source of PAHs at the industrial area was
fossil fuel combustion, coal-burning, industrial furnaces including others. There was a very significant correlation of PAHs
levels between CCF and CAC (R
2 = 0.91). The average concentration of BaP in the industrial area during the sampling period was 5.95ng m−3. It could be concluded the local population appears to be exposed to significantly high cancer risk (exceeding 2ng m−3 in autumn and winter) as compared to the population of other areas.
Water Air and Soil Pollution 06/2007; 183(1):437-446. · 1.63 Impact Factor
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ABSTRACT: Detailed atomistic structures of blend membranes (poly vinyl alcohol (PVA)/(acrylic acid-co-2-acrylamido-2-methylpropylsulfonic acid) (P(AA-AMPS)) were constructed to investigate the sorption and diffusion behavior of gas molecules (water and propylene) in the membranes. Interaction and miscibility between PVA and P(AA-AMPS) were calculated, and it was found that strong intermolecular interaction resulted in good miscibility of PVA and P(AA-AMPS) in the blend. The polymer chains mobility and free volume properties of the blend membranes were characterized. The sorption quantities and sorption sites of water and propylene in the blend membranes were calculated using Grand Canonical Monte Carlo (GCMC) method. The diffusion coefficients of water in the blend membranes were calculated by molecular dynamics (MD) simulation. The simulated results of the membrane structure (chain mobility, free volume properties), the sorption quantities and diffusion coefficients of water/propylene in the blend membranes showed the identical changing trends as the experimental results. Hopefully, this study could offer qualitative insight into the mass transport phenomena within the blend membranes.
Chemical Engineering Science 64(24):5192-5197. · 2.43 Impact Factor
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ABSTRACT: The properties of composite membrane depend immensely on the quality of the interaction between the support layer and the active layer. This work describes the facile method to improve the interfacial adhesion of the chitosan (CS)/polyethersulfone (PES) composite membranes mediated by dopamine. A thin adherent poly-dopamine film was formed through the spontaneous deposition on top of the PES support layer, and acted as a transition layer. The CS active layer was subsequently coated on dopamine transition layer. The optimal recipe and procedure for CS/PES composite membrane preparation was as follows: PES support layer was treated with 4 mg ml−1 dopamine solution (pH 9.47, dipping time 48 h), fully dried and then coated with crosslinked chitosan. The resulting CS active layer was about 10 μm thick. The as-prepared CS/PES composite membrane exhibited high pervaporation flux of 2.28 kg m−2 h−1 for 90 wt.% aqueous alcohol solution in the feed at 80 °C. It could be derived that dopamine mediation would be an effective method for preparing composite membranes with stable structural and high pervaporation flux.
Journal of Membrane Science.
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ABSTRACT: Titanate nanotubes (TNTs) are prepared by a hydrothermal method, and then modified with poly(aspartic acid). Subsequently, they are incorporated into chitosan (CS) to fabricate the modified TNTs (MTNTs)-embedded chitosan hybrid membranes supported by the polyacrylonitrile (PAN) membrane (CS-MTNTs/PAN) and utilized for isopropanol dehydration. The physicochemical properties including physical morphology, chemical interaction, hydrophilicity, crystallinity, thermal stability and free-volume of CS-MTNTs hybrid separation layers are characterized by SEM, FTIR, water contact angle, XRD, TG and PALS analysis, respectively. It is found that the modification of poly(aspartic acid) can apparently improve the interfacial morphology and compatibility between TNTs and membrane matrix. Moreover, the superior isopropanol dehydration performance of CS-MTNTs/PAN composite membranes compared to pure CS membrane is verified via pervaporation experiments, which can be ascribed to the strong hydrophilicity and tubular structure of TNTs. For 90 wt% aqueous solution of isopropanol, the CS-MTNTs/PAN composite membrane containing 6 wt% MTNTs acquires the highest permeation flux and separation factor of 1498 g/m2 h and 6237 at 80 °C, respectively. These results indicate the promising application potential of nanotube-filled membranes in the pervaporative dehydration of alcohols.Highlights► Titanate nanotube via the hydrothermal method is modified with poly(aspartic acid). ► Modified nanotubes are filled into the chitosan matrix to fabricate hybrid membranes. ► The membranes displayed high separation performance in isopropanol dehydration.
Chemical Engineering Science. 66(18):4221-4228.
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ABSTRACT: Esterification assisted by pervaporation separation can enhance the yield of ester for thermodynamically or kinetically limited reaction via selective removal of water from the reaction mixture. In the present study, organic–inorganic hybrid membranes were prepared by in situ hydrolysis and condensation of tetraethoxysilane (TEOS) within chitosan (CS) aqueous solution for pervaporation-assisted esterification of lactic acid with ethanol, catalyzed by Amberlyst 15 ion-exchange resin. The composition and structural properties of CS–TEOS hybrid membranes were investigated by FT-IR, XRD, TGA and contact angle. The dehydration performances of hybrid membranes were evaluated by pervaporation of aqueous ethanol solution. Comparing with CS pristine membrane, CS–TEOS hybrid membranes exhibited remarkably enhancing pervaporation property. Pervaporation-assisted esterification results suggested that the incorporation of pervaporation process to preferentially remove water from the reaction mixture substantially enhanced the yield of ethyl lactate from 66 wt.% to 80 wt.%. The effects of membrane casting solution recipe, reaction temperature, initial molar ratio of ethanol to lactic acid and catalyst loading amount on the process performance have been examined in detail.
Chemical Engineering Journal.
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ABSTRACT: The structural stability of chitosan (CS)/polyacrylonitrile (PAN) composite membrane for pervaporation dehydration was improved by the introduction of mussel-adhesive-mimetic molecule, carbopol (CP). The composite membranes were simply fabricated by layer-by-layer technique, in which CP as an intermediate layer bridging the CS active layer and the PAN support layer. The structure and morphology of composite membranes were characterized by Fourier transform infrared spectroscopy (FT-IR) and field emission scanning electron microscope (FESEM). The methylene iodide contact angle measurement, T-peel test and molecular dynamics (MD) simulation were employed to analyze the wetting characteristics, adhesion strength and interaction at the interface. Positron annihilation lifetime spectroscopy (PALS) was employed to probe the fractional free-volume properties of the CS active layer. The membrane pervaporation performance was investigated by varying the molecular weight (CP981, 940, 974) and concentration of CP as well as the cross-linking degree of the CS active layer. When the concentration of CP974 was 0.5 wt.%, GCCS(60)/CP(0.5)/PAN composite membrane displayed the permeation flux of 1247 g/(m2 h) and separation factor of 256 for ethanol dehydration at 353 K. Furthermore, the enhancement of the long-term operation stability of membrane by incorporating the CP layer was also verified.
Journal of Membrane Science.
