Highly luminescent and stable CsPbBr3 perovskite nanocrystals coated with polyethersulfone for white light-emitting diode applications.

Simultaneously improving the stability and photoluminescence quantum yield (PLQY) of all inorganic perovskite nanocrystals (NCs) is crucial for their practical utilization in various optoelectronic devices. Here, CsPbBr3 NCs coated with polyethersulfone (PES) were prepared via an in-situ co-precipitation method. The sulfone groups in PES bind to undercoordinated lead ion (Pb2+) on the CsPbBr3 NCs, resulting in significant reduction of surface defects, thus enhancing the PLQY from 74.2% to 88.3%. Meanwhile, the PES-coated NCs exhibit high water resistance and excellent heat and light stability, maintaining over 85% of the initial PL intensity under thermal aging (70°C, 4 h) and continuous 365 nm ultraviolet (UV) light irradiation (24 W, 8 h) conditions. By contrast, the PL intensity of the control NCs dramatically dropped to less than 40%. Finally, a diode emitting bright white light was fabricated utilizing the PES-coated CsPbBr3 NCs, which exhibits a color gamut of ~110% NTSC standard.

Breast cancer nipple discharge exosomal microRNAs are stable under degradative conditions.

We have previously shown that microRNAs (miRNAs) in nipple discharge are potential diagnostic biomarkers. In particular, exosomes are present in nipple discharge. Herein, we sought to elucidate the protective role of exosomes on miRNAs in nipple discharge and investigate the stability of miRNAs encapsulated in exosomes under degradative conditions. A novel TTMAAlPc-RNA complex method was used to measure the RNase concentration in colostrum and nipple discharge. Quantitative real-time polymerase chain reaction was performed to test the stability of exogenous synthetic miRNAs (cel-lin-4-5p and cel-miR-2-3p) and endogenous miRNAs (hsa-miR-4732-5p, hsa-miR-3646, hsa-miR-4484, and kshv-miR-K12-5-5p). RNase was present and functional in colostrum and nipple discharge. Endogenous miRNAs were more stably expressed compared to exogenous miRNAs at room temperature and 4°C. Triton X-100 (1%, 30 min) destroyed the exosomal membrane, causing RNA degradation in colostrum but not in nipple discharge. Therefore, we confirmed that exosomes in colostrum and nipple discharge could protect miRNAs from degradation by RNase. Exosomes in nipple discharge may be more resistant to Triton X-100 lysis compared to those in the colostrum. Exosomal miRNAs in nipple discharge in breast cancer are stable under degradative conditions. Differential Triton X-100 sensitivity of exosomes of nipple discharge and colostrum warrants further investigation.

Engineering the Outer Membrane Could Facilitate Better Bacterial Performance and Effectively Enhance Poly-3-Hydroxybutyrate Accumulation.

Poly-3-hydroxybutyrate (PHB) is an environmentally friendly polymer and can be produced in Escherichia coli cells after overexpression of the heterologous gene cluster phaCAB. The biosynthesis of the outer membrane (OM) consumes many nutrients and influences cell morphology. Here, we engineered the OM by disrupting all gene clusters relevant to the polysaccharide portion of lipopolysaccharide (LPS), colanic acid (CA), flagella, and/or fimbria in E. coli W3110. All these disruptions benefited PHB production. Especially, disrupting all these OM components increased the PHB content to 83.0 wt% (PHB content percentage of dry cell weight), while the wild-type control produced only 1.5 wt% PHB. The increase was mainly due to the LPS truncation to Kdo2 (3-deoxy-d-manno-octulosonic acid)-lipid A, which resulted in 82.0 wt% PHB with a 25-fold larger cell volume, and disrupting CA resulted in 57.8 wt% PHB. In addition, disrupting LPS facilitated advantageous fermentation features, including 69.1% less acetate, a 550% higher percentage of autoaggregated cells among the total culture cells, 69.1% less biofilm, and a higher broken cell ratio. Further detailed mechanism investigations showed that disrupting LPS caused global changes in envelope and cellular metabolism: (i) a sharp decrease in flagella, fimbria, and secretions; (ii) more elastic cells; (iii) much greater carbon flux toward acetyl coenzyme A (acetyl-CoA) and supply of cofactors, including NADP, NAD, and ATP; and (iv) a decrease in by-product acids but increase in γ-aminobutyric acid by activating σE factor. Disrupting CA, flagella, and fimbria also improved the levels of acetyl-CoA and cofactors. The results indicate that engineering the OM is an effective strategy to enhance PHB production and highlight the applicability of OM engineering to increase microbial cell factory performance. IMPORTANCE Understanding the detailed influence of the OM on the cell envelope and cellular metabolism is important for optimizing the E. coli cell factory and many other microorganisms. This study revealed the applicability of remodeling the OM to enhance PHB accumulation as representative inclusion bodies. The results generated in this study give essential information for producing other inclusion bodies or chemicals which need more acetyl-CoA and cofactors but less by-product acids. This study is promising to provide new ideas for the improvement of microbial cell factories.

Increasing L-threonine production in Escherichia coli by overexpressing the gene cluster phaCAB.

L-Threonine is an important branched-chain amino acid and could be applied in feed, drugs, and food. In this study, L-threonine production in an L-threonine-producing Escherichia coli strain TWF001 was significantly increased by overexpressing the gene cluster phaCAB from Ralstonia eutropha. TWF001/pFW01-phaCAB could produce 96.4-g/L L-threonine in 3-L fermenter and 133.5-g/L L-threonine in 10-L fermenter, respectively. In addition, TWF001/pFW01-phaCAB produced 216% more acetyl-CoA, 43% more malate, and much less acetate than the vector control TWF001/pFW01, and meanwhile, TWF001/pFW01-phaCAB produced poly-3-hydroxybutyrate, while TWF001/pFW01 did not. Transcription analysis showed that the key genes in the L-threonine biosynthetic pathway were up-regulated, the genes relevant to the acetate formation were down-regulated, and the gene acs encoding the enzyme which converts acetate to acetyl-CoA was up-regulated. The results suggested that overexpression of the gene cluster phaCAB in E. coli benefits the enhancement of L-threonine production.

Effect of treatment of obstructive sleep apnea on depressive symptoms: systematic review and meta-analysis.

BACKGROUND: Obstructive sleep apnea (OSA) is associated with increased morbidity and mortality, and decreased quality of life. Treatment with continuous positive airway pressure (CPAP) or mandibular advancement devices (MADs) is effective for many symptoms of OSA. However, it remains controversial whether treatment with CPAP or MAD also improves depressive symptoms. METHODS AND FINDINGS: We performed a systematic review and meta-analysis of randomized controlled trials that examined the effect of CPAP or MADs on depressive symptoms in patients with OSA. We searched Medline, EMBASE, the Cochrane Central Registry of Controlled Trials, and PsycINFO from the inception of the databases until August 15, 2014, for relevant articles. In a random effects meta-analysis of 19 identified trials, CPAP treatment resulted in an improvement in depressive symptoms compared to control, but with significant heterogeneity between trials (Q statistic, p<0.001; I(2) = 71.3%, 95% CI: 54%, 82%). CPAP treatment resulted in significantly greater improvement in depressive symptoms in the two trials with a higher burden of depression at baseline (meta-regression, p<0.001). The pooled standardized mean difference (SMD) in depressive symptoms with CPAP treatment in these two trial populations with baseline depression was 2.004 (95% CI: 1.387, 2.621), compared to 0.197 (95% CI: 0.059, 0.334) for 15 trials of populations without depression at baseline. Pooled estimates of the treatment effect of CPAP were greater in parallel arm trials than in crossover trials (meta-regression, p = 0.076). Random effects meta-analysis of five trials of MADs showed a significant improvement in depressive symptoms with MADs versus controls: SMD = 0.214 (95% CI: 0.026, 0.401) without significant heterogeneity (I(2) = 0%, 95% CI: 0%, 79%). Studies were limited by the use of depressive symptom scales that have not been validated specifically in people with OSA. CONCLUSIONS: CPAP and MADs may be useful components of treatment of depressive symptoms in individuals with OSA and depression. The efficacy of CPAP and MADs compared to standard therapies for depression is unknown. Please see later in the article for the Editors' Summary.

Solid-phase extraction based on chloromethylated polystyrene magnetic nanospheres followed by gas chromatography with mass spectrometry to determine phthalate esters in beverages.

An ultrasound-assisted magnetic solid-phase extraction procedure with chloromethylated polystyrene-coated Fe3 O4 nanospheres as magnetic adsorbents has been developed to determine eight phthalate esters (bis(4-methyl-2-pentyl) phthalate, dipentyl phthalate, dihexyl phthalate, benzyl butyl phthalate, bis(2-butoxyethyl) phthalate, dicyclohexyl phthalate, di-n-octyl phthalate, and dinonyl phthalate) simultaneously in beverage samples, in combination with gas chromatography coupled to tandem mass spectrometry for the first time. Several factors related to magnetic solid-phase extraction efficiencies, such as amount of adsorbent, extracting time, ionic strength, and desorption conditions were investigated. The enrichment factors of the method for the eight analytes were over 2482. A good linearity was observed in the range of 10-500 ng/L for bis(2-butoxyethyl) phthalate and 2-500 ng/L for the other phthalate esters with correlation coefficients ranging from 0.9980 to 0.9998. The limits of detection and quantification for the eight phthalate esters were in the range of 0.20-2.90 and 0.67-9.67 ng/L, respectively. The mean recoveries at three spiked levels were 75.8-117.7%, the coefficients of variations were <11.6%. The proposed method was demonstrated to be a simple and efficient technique for the trace analysis of the phthalate esters in beverage samples.

Hydrophobic-action-driven removal of six organophosphorus pesticides from tea infusion by modified carbonized bacterial cellulose.

The abuse of organophosphorus pesticides (OPPs) in tea planting makes it easy to transfer from tea into its infusion, bringing potential health risks to consumers. Thus, it is essential to adopt reliable techniques to remove OPPs from tea infusion. In this study, three treatment methods were used to modify carbonized bacterial cellulose (CBC) to improve its adsorption performance. Among them, CBC treated by hydrazine hydrate (N-CBC) had the best adsorption effect, whose removal rate for dicrotophos is 13 times that of CBC. The in-depth study of adsorption mechanism proved that hydrophobic interaction dominated the adsorption of OPPs onto N-CBC. The pseudo-second-order kinetic model and Langmuir isotherm model were more suitable to describe the process. Additionally, there were no significant changes in tea infusion quality after N-CBC treatment. This work clarifies that N-CBC benefitted from simple preparation method, excellent adsorption performance and unique adsorption mechanism has potential applications in tea infusion.

In situ boron-doped cellulose-based biochar for effective removal of neonicotinoids: Adsorption mechanism and safety evaluation.

Biochar materials have been widely employed for adsorption of pollutants, which necessitates further consideration of their efficiency and safety in environmental remediation. In this study, a porous biochar (AC) was prepared through the combination of hydrothermal carbonization and in situ boron doping activation to effectively adsorb neonicotinoids. The adsorption process was shown to be a spontaneous endothermic physical adsorption process, where the predominant interaction forces between the acetamiprid and AC were electrostatic and hydrophobic interactions. The maximum adsorption capacity was 227.8 mg g-1for acetamiprid and the safety of AC was verified by simulating the situation where the aquatic organism (D. magna) was exposed to the combined system (AC & neonicotinoids). Interestingly, AC was observed to reduce the acute toxicity of neonicotinoids owing to the reduced bioavailability of acetamiprid in D. magna and the newly generated expression of cytochrome p450. Thus, it enhanced the metabolism and detoxification response in D. magna, which reducing the biological toxicity of acetamiprid. This study not only demonstrates the potential application of AC from a safety perspective, but also provides insight into the combined toxicity caused by biochar after adsorption of pollutants at the genomic level, which fills the gap in related research.

Quickly and efficiently remove multiple pesticides in tea infusions by low-cost carbonized bacterial cellulose.

Soaking tea leaves make tea consumers exposure to pesticide residues more easily. However, there are few studies on the removal of pesticides in tea infusions. Therefore, a low-cost carbonized bacterial cellulose material was prepared by direct calcination method, and used to remove multiple pesticides in tea infusions quickly and efficiently. CBC-350 has the best removal efficiency for 9 pesticides and then screened the best adsorption conditions. The adsorption isotherm experiment was carried out and indicated that the adsorption process was in consist with the Freundlich model. The thermodynamic parameters are also calculated. Moreover, the adsorption mechanism was discussed, which suggests that π-π interaction and hydrophobic action are the driving force during the adsorption process. Exhilaratingly, the CBC-350 also has excellent adsorption capacity compared to other adsorbents and can be reused at least five times.

A mild and one-pot method to activate lignin-derived biomass by using boric acid for aqueous tetracycline antibiotics removal in water.

A mild and one-pot activation approach of activated carbon was found. The feasibility of boric acid as the activated reagent which was used for the adsorption of four tetracyclines antibiotics (TCs) in water. Boric acid activated carbon (BAC) from bioresource has a much higher removal efficiency than currently reported biochar. The maximum adsorption capacity of BAC is 173.9 mg/g for TCs. BAC is an ecofriendly, nontoxic, and low-cost absorbent from sawdust waste. BAC and TCs could keep coalescing at least 55 days on the surface without stable release. BAC was fully characterized by using scanning electron microscopy, X-ray photoelectron spectroscopy, X-ray diffraction, Raman, zeta potential, and Brunauer-Emmett-Teller analysis; the large surface area and rich pore structure were proved. The interaction between BAC and TCs are hydrogen bond interaction, π-π interaction, and electrostatic interaction. These interactions are also related to the surface charge of BAC and the TCs' species of ions in different pH. Furthermore, the adsorption kinetics and adsorption isotherm of BAC were studied thoroughly. The pseudo-first-order, pseudo-second-order, intra-particle diffusion, Elovich Langmuir, Freundlich, and Dubinin-Radushkevich models were fitted and the physical adsorption process was proved. After the study on adsorption thermodynamics, adsorption exhibits a spontaneous and favorable process.

Catalytic performance promoted on Pt-based diesel oxidation catalyst assisted by polyvinyl alcohol.

Eliminating vehicle emission is of importance due to the severe limit value. The work reports a convenient strategy of improving dispersion of platinum-based catalyst with the assistance of polyvinyl alcohol in a varied addition amount. Following the "two-step" annealing techniques, the catalytic performance of the polymer-assisted catalysts in diesel was obviously enhanced because of the improved dispersion of the platinum. Based on experimental results, the long chains of polymer resulting in the steric effect are presumed to isolate platinum ion, inhibiting the aggregation of platinum particles and then improving its dispersion. And the hydroxyl bonding between the polymers could convey electron to platinum species, leading to the lower platinum valence state. Both effects are positive resulting in an excellent NO maximum conversion of around 65% at the optimal introduction of 5 mass% of polymer, as the diesel oxidation catalyst (DOC), which could be inclined to a good purification in the diesel aftertreatment. Hopefully, the convenient research method could initiate the exploration and application of polymer-assisted catalysts for well-dispersed noble metal nanoparticles in eliminating exhaust emission.

Truncating the Structure of Lipopolysaccharide in Escherichia coli Can Effectively Improve Poly-3-hydroxybutyrate Production.

Poly-3-hydroxybutyrate is an environmentally friendly polymer with many promising applications and can be produced in Escherichia coli cells after overexpressing the heterologous gene cluster phaCAB. In this study, we found that truncating the structure of lipopolysaccharide in E. coli can effectively enhance poly-3-hydroxybutyrate production. E. coli mutant strains WJW00, WJD00, and WJJ00 were constructed by deleting rfaD from E. coli strain W3110, DH5α, and JM109, respectively. Compared to the controls W3110/pDXW-8-phaCAB, DH5a/pDXW-8-phaCAB, and JM109/pDXW-8-phaCAB, the yield of poly-3-hydroxybutyrate in WJW00/pDXW-8-phaCAB, WJD00/pDXW-8-phaCAB, and WJJ00/pDXW-8-phaCAB cells increased by 200%, 81.5%, and 75.6%, respectively, and the conversion rate of glucose to poly-3-hydroxybutyrate was increased by ∼250%. Further analysis revealed that LPS truncation in E. coli rebalanced carbon and nitrogen metabolism, increased the levels of acetyl-CoA, γ-aminobutyric acid, NADPH, NADH, and ATP, and decreased the levels of organic acids and flagella, resulting in the high ratio of carbon to nitrogen. These metabolic changes in these E. coli mutants led to the significant increase of poly-3-hydroxybutyrate production.

[Effects of oral appliance treatment upon blood pressure in mild to moderate obstructive sleep apnea-hypopnea syndrome].

OBJECTIVE: To evaluate the effects of oral appliance (OA) treatment upon systemic blood pressure (BP) in mild to moderate patients with obstructive sleep apnea-hypopnea syndrome (OSAHS). METHODS: Forty-six consecutive patients diagnosed with OSAHS on polysomnography were divided into OA treatment group (OA group, 25 patients, 15 patients with hypertension) and non-tolerated OA treatment group (N-OA group, 21 patients, 13 patients with hypertension). Polysomnography and 24-hour ambulatory blood pressure monitoring (ABPM) were performed at baseline in two groups. Polysomnography and ABPM were repeated after a completion of 12 weeks of treatment in OA group and after a cessation of treatment for 12 weeks in N-OA group. Hypertensive patients in two groups continued taking the same kind and the same dose of antihypertensive agents during the period of study. RESULTS: There was no significant difference between the two groups in age, body mass index, Epworth sleepiness score (ESS), apnoea-hypopnoea index (AHI), arousal index (AI) and minimum arterial oxygen saturation (MSaO2) at baseline. After a 12-week treatment, OA group showed significant improvement in AHI [(7.0 +/- 3.8) vs (21.0 +/- 6.5) per hour, P < 0.01], AI [(22.9 +/- 6.3) vs (32.2 +/- 9.3) per hour, P < 0.01] and MSaO2 (86.8% +/- 3.5% vs 80.0% +/- 5.2%, P < 0.01), while nocturnal mean systolic blood pressure (SBP) and diastolic blood pressure (DBP), 24-hour and diurnal SBP, and nocturnal mean artery pressure (MAP) were significantly reduced [(121.3 +/- 7.0) vs (125.3 +/- 9.3), (76.1 +/- 6.1) vs (78.8 +/- 6.8), (127.2 +/- 7.5) vs (129.4 +/- 8.8), (131.5 +/- 6.9) vs (133.6 +/- 8.1), and (91.2 +/- 6.4) vs (94.3 +/- 7.6) mm Hg respectively, all P < 0.01]. The reduction in nocturnal MAP was significantly correlated to improvement in AI(r = 0.37, P = 0.005) and AHI (r = 0.32, P = 0.011), to baseline nocturnal mean blood pressure (SBP: r = 0.39, P = 0.015; DBP: r = 0.30, P = 0.024). The N-OA group showed no differences in blood pressure variables between baseline and after a cessation of treatment for 12 weeks. CONCLUSION: Oral appliance treatment for mild to moderate OSAHS may lead to a reduction in systemic blood pressure.

In situ fabrication of cobalt nanoflowers on sulfonated and fluorinated poly (arylene ether ketone-benzimidazole) template film for the electrocatalytic oxidation of glucose.

Using sulfonated and fluorinated poly (arylene ether ketone) comprising functional strong coordination group benzimidazole (SPAEK-F-BI) as a template film, a novel fabrication method of cobalt nanoflowers (CoNFs) and non-enzymatic glucose electrochemical sensor was developed in this work. After the precursors Co2+ ions were cooperatively bound by sulfonate and imidazole functionalities contained in SPAEK-F-BI film through ion exchange and strong coordination action, cobalt colloid nuclei were formed and grew to flower-like nanostructures by subsequent in-situ electrochemical reduction on SPAEK-F-BI film modified GCE. Characterization of SPAEK-F-BI film and CoNFs/SPAEK-F-BI film on GCE was performed in detail by FT-IR spectroscopy and scanning electron microscopy (SEM) attached with energy dispersive spectroscopy (EDS), electrochemical impedance spectroscopy (EIS) and cyclic voltammetry (CV). The results of SEM showed that beautiful CoNFs constructed by Co colloid nanosheets with just a few nanometers thickness were well dispersed on uniform SPAEK-F-BI film modified GCE, and the density of CoNFs was mainly influenced by the concentration of the precursor solution CoSO4. The CoNFs/SPAEK-F-BI composite modified electrode exhibited good electrocatalytic activity toward glucose oxidation in 0.1M NaOH solution, and the kinetic parameters of glucose oxidation were determined using chronoamperometry. When it was applied for the determination of glucose by amperometry at a potential of 0.6V versus Ag/AgCl, the linear range from 5µM to 1.14mM and the detection limit of 800nM (S/N = 3) were obtained. Finally, it was successfully employed to detect the glucose in human serum real samples, and the results were agreed closely with those measured in hospital.

FGF receptor-mediated gene delivery using ligands coupled to polyethylenimine.

To obtain new nonviral vectors with high gene delivery efficiency and special cell targeting ability, an attractive strategy is to link ligands to polyethylenimine (PEI). Fibroblast growth factor receptors (FGFRs) are highly expressed on a variety of human cancer cells and are potential targets for cancer gene therapy. In this study, the peptides NH2-Met-Gln-Leu-Pro-Leu-Ala-ThrGly-Gly-Gly-Cys-COOH (MC11) which have been proved to combine specially with the FGFR on cell membrane are coupled to PEI using N-Succinimidyl-3-(2-pyridyldithio) propionate (SPDP) as a linker with different molar ratios (1 : 0.3, 1 : 0.75, 1 : 1.5, and 1 : 3.0) and the new polymer PEI-MC11 is verified by a series of physicochemical methods including 1H-NMR and FTIR. The agarose gel electrophoresis assay, particle size test, zeta potential test, and electron microscope observation show that PEI-MC11 can efficiently condense plasmid DNA into nanoparticles with about 200 nm in diameter and with positive surface charge at the suitable N/P ratio. The MTT assay suggests the decreased toxicity of the polymers. The results of the gene delivery efficiency in vitro show that PEI-MC11/pDNA polyplexes have significantly greater transgene activity than PEI/pDNA in COS-7 and HepG2 cells which express FGFR positively, while no such effect is observed in PC3 cells which have negative FGFR. The enhanced gene delivery efficiency of PEI-MC11 can be blocked by the co-culture of free peptides MC11 before the gene delivery procedure. The synthesized nonviral vector based on PEI with the targeting peptides MC11 for binding FGFR has improved efficiency of gene delivery and targeting specificity in FGFR positive cells. It may have potential application in cancer gene therapy.

Novel acrylonitrile-based copolymers containing phospholipid moieties: synthesis and characterization.

Novel acrylonitrile-based copolymers containing phospholipid moieties were synthesized by a three-step process, which included the copolymerization of acrylonitrile and 2-hydroxyethyl methacrylate (HEMA) in water and the reaction of the resulting poly[acrylonitrile-co-(2-hydroxyethyl methacrylate)]s (PANCHEMA) with 2-chloro-2-oxo-1,3,2-dioxaphospholane (COP) followed by the ring-opening reaction of COP with trimethylamine. The chemical structure of PANCHEMA and the phospholipid-containing acrylonitrile-based copolymers (PLCANCP) was analyzed with FT-IR spectroscopy, (1)H and (31)P NMR, and XPS. Surface properties of the studied copolymers were evaluated by the pure water contact angle, protein adsorption and platelets adhesion measurements. The water contact angle measured by sessile drop method decreased for the polymers in the following sequence: PAN, PANCHEMA, and PLCANCP. The adsorption amount of bovine serum albumin and the adhesive number of platelet followed the same decline sequence. These results demonstrate that the biocompatibility of the acrylonitrile-based copolymer membranes could be improved efficiently by the introduction of phospholipid moieties.

Surface modification of polyacrylonitrile-based membranes by chemical reactions to generate phospholipid moieties.

A novel approach for the surface modification of poly(acrylonitrile-co-2-hydroxyethyl methacrylate) (PANCHEMA) membranes by introducing phospholipid moieties is presented, which involved the reaction of the hydroxyl groups on the membrane surface with 2-chloro-2-oxo-1,3,2-dioxaphospholane (COP) followed by the ring-opening reaction of COP with trimethylamine. The chemical changes of phospholipid-modified acrylonitrile-based copolymers (PMANCP) membranes were characterized by Fourier transfer infrared spectroscopy and X-ray photoelectron spectroscopy. The surface properties of PMANCP membranes were evaluated by pure water contact angle, protein adsorption, and platelet adhesion measurements. Pure water contact angles measured by the sessile drop method on PMANCP membranes were obviously lower than those measured on the PANCHEMA membranes and decreased with the increase of the content of phospholipid moieties on the membrane surface. It was found that the bovine serum albumin adsorption and platelet adhesion were suppressed significantly with the introduction of phospholipid moieties on the membranes surface. These results demonstrated that the described process was an efficient way to improve the surface biocompatibility for the acrylonitrile-based copolymer membrane.

[Separation of carbon dioxide from gas mixture by membrane contactor].

In this paper, membrane contactor made of hydrophobic hollow fiber polypropylene porous membrane (HFPPM) was used for separating carbon dioxide (CO2) from CO2/N2 mixtures. The effects of absorbents, concentration and flow rate of feeding gas and absorbent solution, lumen/shell side processes and gas permeability of HFPPM(P) on the CO2 absorption efficiency were investigated. It was found that the absorption efficiency of three absorbents ranged in order of ethanolamine > sodium hydroxide > diethanol amine. For CO2/N2 mixture of c(in) = 20% and v(in) = 0.5-1.0 m3.h-1, and MEA solution of cMEA = 2.5 mol.L-1 and vL = 40-160 L.h-1, the removal efficiencies of CO2 (eta) and the mass transport coefficients (K) was 9.5% - 99.5% and 4.5-6.8 x 10(-4) m.s.-1 respectively. K of the modules made of HFPPM with larger P was relatively larger. eta in lumen process was 30% larger than that in shell process.