Culture of yeast cells immobilized by alginate-chitosan microcapsules in aqueous-organic solvent biphasic system

Immobilization biocatalysis is a potential technology to improve the activity and stability of biocatalysts in nonaqueous systems for efficient industrial production.Alginate-chitosan(AC)microcapsules were prepared as immobilization carriers by emulsifi cation-internal gelation and complexation reaction,and their contribution on facilitating the growth and metabolism of yeast cells were testifi ed successfully in culture medium-solvent biphasic systems.The cell growth in AC microcapsules is superior to that in alginate beads,and the cells in both immobilization carriers maintain much higher activity than free cells,which demonstrates AC microcapsules can confer yeast cells the ability to resist the adverse effect of solvent.Moreover,the performance of AC microcapsules in biphasic systems could be improved by adjusting the formation of outer polyelectrolyte complex(PEC)membrane to promote the cell growth and metabolic ability under the balance of resisting solvent toxicity and permitting substrate diffusion.Therefore,these findings are quite valuable for applying AC microcapsules as novel immobilization carriers to realize the biotransformation of value-added products in aqueous-solvent biphasic systems.

One-pot degradation of cellulose into carbon dots and organic acids in its homogeneous aqueous solution

As the abundant biopolymer, cellulose can be used as a feedstock for chemicals and materials. Effective conversion of cellulose by simple processes is a key point. Degradation of cellulose in its homogeneous solution is attractive for the molecular chains are free and spread. Here,microcrystalline cellulose was first dissolved in aqueous solution of Na OH and urea, and then hydrothermal reaction was carried out at various temperature and time. Fluorescence carbon dots(CDs) were generated accompanied with six organic acids: oxalic acid, formic acid, malonic acid, lactic acid, acetic acid, and fumaric acid. The yields of all organic acids and CDs, and the fluorescence quantum yield(QY) of CDs were studied at different reaction conditions. It was found that the maximum yield of organic acids and CDs are 80.1% and 6.03%, respectively, and the highest QY of the CDs is 10.9%. Fluorescence studies reveal that the as-prepared CDs has efficient selectivity and sensitivity toward iron ions in acidic condition, indicating it is a potential fluorescent sensor to the detection of Fe3+. Importantly, it provides a panorama to summary the degradation routes of cellulose in its homogeneous aqueous solution with both organic molecules and CDs as products.

STUDIES ON REVERSE OSMOSIS SEPARATION OF AQUEOUS ORGANIC SOLUTIONS BY PAA/PSF COMPOSITE MEMBRANE

The reverse osmosis (RO) separation of aqueous organic solutions, such as alcohols, amines, aldehydes, acids, ketones, and esters etc., by PAA (polyacrylic acid)/PSF (polysulfone) composite membrane has been studied. It was found that the separation results for aliphatic alcohols, amines and aldehydes are satisfactory, the solute rejection (R-a) and the volume fluxes of solutions (J(V)) for 1000 ppm ethanol, ethylamine and ethyl aldehyde are 66.2%, 61.0%, 84.0% and 0.90 x 10(-6), 0.35 x 10(-6), 0.40 X 10(-6) m(3)/m(2) . s, respectively, at 5.0 MPa and 30 degrees C. R-a increased with increasing molecular weights of alcohols, amines and aldehydes, and the R-a for n-amyl alcohol, n-butylamine and n-butyl aldehyde reached 94.3%, 88.6% and 96.0%, respectively. Satisfactory separation results (R-a > 70%) for ketones, esters, phenols and polyols have been obtained with the PAA/PSF composite membrane. The effect of operating pressure on the properties of reverse osmosis has also been investigated. Analysis of experimental data with Spiegler-Kedem's transport model has been carried out and the membrane constants such as reflection coefficient sigma, solute and hydraulic permeabilities omega and L-p for several organic solutes have been obtained.

Thermoregulated Organic Biphasic Hydrogenation of 1-Octene Catalyzed by Ru/PETPP Complex

Thermoregulated organic biphasic system composed of triethylene glycol monomethyl ether （TGME） and n-heptane was first applied to the hydrogenation of 1-octene. Under the optimal conditions： P（H2）=5.0MPa, T=80℃, t=3h, 1-octene/Ru=1000 （molar ratio）, the yield of n-octane reached up to 99.6%. Furthermore, the simply decanted catalyst could be reused for 10 times without apparent loss of catalytic activity.

A Simple Theoretical Approach of Aqueous Solutions of Salts and Organic Solvents in Paper Chromatography

The purpose of this study is to determine the properties of the solvents responsible of the chromatographic phenomenon. A simple and homogeneous system of ascending chromatography on paper is described, allowing varying only one of the factors constituting it. This method made it possible to determine constants by means of a simple equation. The validity of the method is deduced from the good agreement between its mathematical expression and the experimental values obtained.

Asymmetric Synthesis of (-)-1-Trimethylsilyl-ethanol with Immobilized Saccharomyces Cerevisiae Cells in Water/Organic Solvent Diphasic System

Asymmetric synthesis of (-)-1-trimethylsilyl-ethanol with immobilized Saccharomyces cerevisiae cells in water/organic solvent biphasic system was studied. The effects of shake speed, hydrophobicity of organic solvent, volume ratio of water phase to organic phase, pH value of aqueous phase and reaction temperature on the initial reaction rate, maximum yield and enantiomeric excess (ee) of the product were systematically explored. All the above-mentioned factors had significant influence on the reaction. n-Hexane was found to be the best organic solvent for the reaction. The optimum shake speed, volume ratio of water phase to organic phase, pH value and reaction temperature were 150 r.min-1, 1/2, 8 and 30 ℃ respectively, under which the maximum yield and enantiomeric excess of the product were as high as 96.8% and 95.7%, which are 15% and 16% higher than those of the corresponding reaction performed in aqueous phase. To our best knowledge, this is the most satisfactory result obtained.

Rh nanoparticles stabilized by PEG-substituted triphenyl-phosphine:A highly active and recyclable catalyst for aqueous biphasic hydrogenation of benzene

Rh nanoparticles stabilized by PEG-substituted triphenyl-phosphine（PETPP,P[C6H4-p-（OCH2CH2）nOH]3） combining double stabilization effects demonstrated high activity and good recyclability in aqueous biphasic hydrogenation of benzene.The value of turnover frequency（TOF） was 3333 h^-1.Furthermore,the rhodium nanoparticle catalyst could be easily recycled for five times without loss in activity.

Synthesis and Characterization of Polystyrene/Nanosilica Organic-Inorganic Hybrid

A polystyrene（PS）/nanosilica organic-inorganic hybrid material was prepared from styrene monomer and commercial aqueous silica sol containing large amounts of Si-OH by means of emulsion polymerization. The nanosilica sol was modified by the addition of the reactive coupling agent methacrylexy propyltrimethoxysilane （ MPS）, and the resulting latex particles were protected by surfactants such as sodium dodecyl sulphonate（ SDS）, hydroxypropyl methyl cellulose （ HMPC）, and poly （vinylpyrrolidone） （PVP）. The effects of the type of surfactant, the amount of surfactant, and the coupling agent on the shape and stability of the resulting latex particles were investigated. The TEM observation indicates that among SDS, HMPC, and PVP, SDS is the best surfactant. When the content of SDS is 0. 5% and the amount of MPS is 7% in the system, the latex with obvious core-shell structure could be obtained. The average diameters of the monodispersed particles range from 182 to 278 nm, and the average number of silica beads for each composite are 1325 and 4409, respectively. The FrIR analysis shows that PS was chemically linked to silica through MPS. The thermal gravimetric analysis shows that when there is a higher silica content, the hybrid composites have a better heat resistance.

有机电极材料在水系电池中的应用研究进展

与商业化电池相比,水系有机电池(AOBs)具有低成本、高安全性、环保等特点,使其更适用于便携电子设备和电网储能应用。电极材料作为水系有机电池重要组成部分,在实现电池的高容量和长循环寿命方面起到至关重要的作用。基于绿色发展的需求,有机电极材料应具备理论比容量高、资源丰富、设计灵活性强等优点。本文综述了不同储能机理的有机电极材料的最新研究进展,包括羰基化合物、亚胺化合物、导电聚合物、COFs材料、MOFs材料以及复合材料等。同时总结了有机电极材料在水系电池中的导电性和溶解性问题,并提出了不同的解决策略。最后,讨论了水系有机电池的关键挑战以及未来努力方向,未来仍需要更多具有更好电子导电性和快速动力学的电极材料应用于水系有机电池。

聚酰亚胺/UIO-66薄层纳米复合膜的制备及其纳滤性能

传统纳滤膜面临“trade-off”效应,不能够在保证截留的情况下提高膜通量.为解决这一问题,将UiO-66和UiO-66-NH 22种金属有机框架(MOFs)纳米材料分别引入水相和有机相,通过界面聚合反应,辅以亚胺化处理制备4种不同的聚酰亚胺(PI)复合纳滤(NF)膜,研究UiO-66的氨基化及不同添加方式对膜的结构及分离性能的影响.结果表明,与纯PI NF膜相比,4种PI复合NF膜具有更好的亲水性.UiO-66-NH 2添加水相具有最佳的纳滤性能,对CaSO_(4)的截留为91%,水通量为219 L/(m^(2)·h·MPa).4种PI复合NF膜在有机溶剂(THF、DMAc、MT、NMP)中浸泡48 h后,其通量衰减<0.1%,CaSO_(4)的截留率变化<1%;在120 h的长期运行中,通量衰减量在9~17 L/(m^(2)·h·MPa)之间,具有较好的稳定性.

一种吡嗪基共价有机聚合物的制备及在水系锌离子电池正极中的应用

共价有机聚合物(COPs)是由有机小分子单体聚合而成,具有通过共价键连接的高度交联网络结构,因此展现出独特的电化学特性.在水系锌离子电池(AZIBs)领域,COPs作为电极材料,参与离子嵌入与脱嵌,因其特有的氧化还原活性位点和稳定的框架结构而备受关注.本文报道了一种新型的含有多种电化学活性位点(如吡嗪基、苯亚胺基和羰基等)的共价有机聚合物TAPT-HAT-COP,并将其用作AZIBs的正极材料.实验结果表明,该共价有机聚合物材料展现了优异的倍率性能.在0.5 A/g的电流密度下,首次放电比容量达到137 mA·h·g^(-1);在5 A/g的高电流密度下,经过4000次循环后仍能保持45.4%的容量.本文研究结果为有机正极材料的设计提供了新的思路,并可为开发先进的水系锌离子电池新型有机正极材料提供参考.

生物质含氧有机废液水相重整制氢技术应用研究进展

氢能具有清洁、环保、能量密度大、易于运输分配等优势。生物质含氧有机废液水相重整制氢技术作为一种极具前景的废液利用手段,不仅可以减轻社会能源和经济负担,还能妥善处理废液排放带来的环境污染问题。针对氢气供应和废液处理两类关乎保护环境和节约资源两大基本国策的焦点问题,综述了来自生活、农林、食品三类应用领域产生的不同生物质含氧有机废液水相重整制氢反应的研究进展;从反应的制氢性能和产物分布入手分析反应原料、条件、机制等因素对微观反应的影响,同时延伸到废液水相重整制氢技术向实际应用推广的关键问题;最后,针对现阶段生物质含氧有机废液水相重整制氢技术发展面临的主要技术瓶颈攻克提出了几点建议,并对该技术在环保和氢能低成本制备领域的发展前景进行了展望。

异氟尔酮二胺-水二元固-液相变吸收剂捕集CO_(2)机制

固-液相变吸收剂在CO_(2)负荷调控下可发生相变形成固体产物,具有易分离、操作简便的优势,但现有体系大多需有机分相剂调控才能发生固液相变,存在分相剂易挥发损耗、富液黏度大等瓶颈。本研究构建了异氟尔酮二胺(IPDA)-水二元固-液相变吸收体系,无需分相剂,水相溶液吸收CO_(2)后即可发生固液相变。研究表明,1.00 mol·L^(-1)IPDA水溶液在313.15 K下饱和吸收负荷高达0.85 mol CO_(2)·mol^(-1),吸收产物为白色晶体粉末且富集在溶液下层,富液体积占总溶液体积的43.60%,而CO_(2)富集率达93.98%,此时,上层贫相黏度为1.08 mPa·s。富相固体产物分离熔融后在393.15 K温度条件下解吸60 min,再生效率为98.31%。经5次循环吸收-解吸,再生容量仍保持初始容量的80%以上,具有良好的重复利用性。^(13)C核磁共振(NMR)表征分析表明,IPDA与CO_(2)反应生成IPDA-氨基甲酸盐与碳酸氢盐,大多聚集在富相中,仅少量氨基甲酸盐溶于贫相中。解吸完成后,样品未见CO_(2)产物峰,进一步证明了IPDA-H_(2)O可完全解吸。量子化学计算证明,吸收前IPDA与水偶极矩接近,极性相近可互溶,吸收后形成的产物偶极矩低、极性小,产物间的分子内氢键高于产物和水的氢键,产物晶格能增加。因此,产物从溶液中析出,无需分相剂调控,即可在水中发生固液相变。

超级电容器用低温电解液研究进展

电解液作为超级电容器的重要组成部分,是提高超级电容器低温性能的关键。常规电解液高冰点以及低温下离子电导率的不足,极大地限制了超级电容器在低温环境下的应用。降低电解液高冰点的同时确保具有高离子电导率、低黏度和优异化学稳定性等关键特性是目前的研究重点。从水系和非水电解液(包括有机电解液和离子液体)的角度出发,总结了以往为解决相关问题所采取的策略和方法,并对超级电容器低温电解液的发展方向提出展望。

铁锂云母精矿浸出液萃取法提锂研究

以铁锂云母矿石经焙烧—水浸获得水浸液为研究对象,明晰了溶液中钙、镁离子对萃取过程中两相分离的影响,考察了碳酸钠和氢氧化钠用量、水油相比对钙镁脱除效果及脱杂浸出液中锂萃取效果的影响。结果表明:铁锂云母矿石浸出液分别加入锂当量100%和镁摩尔量4倍的碳酸钠和氢氧化钠,在常温下反应1 h后,液固分离获得脱杂浸出液,钙、镁脱除率分别为>99.9%和82.53%;脱杂浸出液采用实验室改性后的M54-100-Cyanex923-磺化煤油萃取体系在O/A=1.5下模拟三级逆流萃取,Li、Na萃取率分别为90.85%和0.04%,载锂有机相在O/A=25下采用5.5 mol/L HCl模拟三级逆流反萃,Li的反萃率>99.9%,富锂反萃液中锂含量在26 g/L左右,一步实现锂的提纯和富集。

共价有机框架材料在水系锌离子电池正极中的应用

水系锌离子电池(AZIB)因其成本低、安全性高和环境友好等特性而备受关注。目前,AZIB正极材料主要为无机材料,其锌离子扩散动力学迟缓、库仑效率不高、循环稳定性欠佳以及环境危害性等问题,严重制约了它的应用。共价有机框架材料(COF)作为一种新型有机正极材料,以其高比表面积、高孔隙率、优异的电化学性能以及环境友好特性受到关注。本文综述了COF应用于AZIB正极中的最新研究进展,包括含羰基、含氮和其他正极材料的设计策略和性能,并探讨了当前面临的挑战和未来发展机遇。

钠离子电池电解液溶剂化结构对SEI的影响

在钠离子电池中电解液是关键组成部分,其内部的溶剂化结构对固体电解质界面(SEI)的形成和组成具有重要影响,并直接影响钠离子电池的电化学性能。文章探讨钠离子电池电解液中溶剂化结构对SEI性质和电池性能的影响机制,总结高浓度电解液溶剂化结构研究的相关成果,探讨溶剂浓度、种类及溶剂化结构对SEI的影响,阐述了电解液中阴阳离子、溶剂分子间作用与钠离子电池性能之间的构效关系。

Asymmetric Reduction of 3,5-Bistrifluoromethyl Acetophenone with NADH Regeneration by Immobilized Cells of Saccharomyces rhodotorula in Aqueous-Organic Solvent Biphasic System

Asymmetric reduction of 3,5-bistrifluoromethyl acetophenone to produce(S)-3,5-bistrifluoromethylphenyl ethanol was successfully carried out with sodium alginate immobilized Saccharomyces rhodotorula cells in an aqueous-organic solvent biphasic system.The possible influential factors were examined thoroughly according to their effects on conversion rate and e.e of the product.Organic solvents were rated by their biocompatibility and conversion potential.The immobilized cells [125 mg/mL in 20 mmol/L Tris-HCl buffer and 5%(j) octane at pH 8] showed the best conversion with a substrate concentration of 1.42 g/L at 30℃ with glucose as co-substrate for cofactor regeneration.Sequential 8-batch process was carried out with immobilized cells with a slow decrease in conversion and e.e.The immobilized cells showed stable catalytic activity with 50% reserved activity and are superior especially in reusability in comparison with resting cells.

Prediction of Aqueous Solubility for 209 Polychlorinated Diphenyl Ethers from Molecular Structural Parameters by DFT Method

Optimized calculations of 209 polychlorinated diphenyl ethers （PCDEs） and diphenyl ethers were carried out at the B3LYP/6-31G^＊ level with the Gaussian 98 program. Based on the theoretical linear solvation energy relationship （TLSER） model, the obtained structural parameters were taken as theoretical descriptors to establish the novel QSPR model for predicting aqueous solubility （-lgSw） of PCDEs. The model obtained in this work contains two variables： mean molecular polarizability （a） and the most positive partial charge on a hydrogen atom （qH^＋）, of which RE = 0.9606 and SD = 0.32. And the results of cross-validation test also show that the model exhibits optimum stability and better predictive power. Moreover, the predictive power of the new model is better than that of MCIs method.