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51.
A new and effective liquid membrane process to achieve both separation and enrichment simultaneously of weak organic acids or bases was developed. The process utilizes effectively the difference in the apparent partition coefficient of the constituent species between the aqueous and organic phases, and uses the change of the apparent partition coefficients with the hydrogen ion concentration of the aqueous phase. For such a fundamental model apparatus as a diaphragm diffusion cell being operated batch wise, the effects of pK value of solutes, permeability of solutes through the membrane, volume ratio of liquids in two aqueous phases, and pH value of aqueous phase on enrichment factor and selectivity for the solute to be concentrated were discussed analytically. Separation and enrichment were demonstrated using aqueous mixed solutions of fumaric acid and L-malic acid. The results were in good agreement with the theoretical predictions. 相似文献
52.
An algorithm has been developed and tested for steady-state liquid-liquid extraction, using rectangular coordinates. It is capable of handling common types of stagewise contact, i.e., single stage extraction, multistage cross-current, and continuous countercurrent multistage extraction. The results depend on the nature of the extraction scheme and the extent of separation desired. While equilibrium data for some systems are stored in its data bank, the present portable computer simulator ( LIQEXT) has the flexibility of reading equilibrium data for other systems, as well as overriding stored data
Both design and rating cases can be performed. In the design mode, i.e., given the feed and solvent rates and the outlet concentration, it calculates the number of stages, the exit stream flow rates, and the concentration profile. In the rating ( or simulation) mode, i.e., given the feed and solvent rates, and the number of stages, it computes the exit streams flow rates and compositions, and the concentration profile. In both cases a graphical output of the concentration profile is produced, either on the screen or on a hard-copy plotter. 相似文献
Both design and rating cases can be performed. In the design mode, i.e., given the feed and solvent rates and the outlet concentration, it calculates the number of stages, the exit stream flow rates, and the concentration profile. In the rating ( or simulation) mode, i.e., given the feed and solvent rates, and the number of stages, it computes the exit streams flow rates and compositions, and the concentration profile. In both cases a graphical output of the concentration profile is produced, either on the screen or on a hard-copy plotter. 相似文献
53.
Terpolymers based on N‐isopropylacrylamide, sodium 2‐acrylamido‐2‐methyl‐propanesulfonate, and N‐tert‐butylacrylamide were synthesized by free‐radical copolymerization with 2,2′‐azobisisobutyronitrile as an initiator. The lower critical solution temperatures (LCSTs) of the linear polymer aqueous solutions were determined by the measurement of the transmittance on UV at different temperatures. The influence of the polymer concentration, polymer composition, and ionic strength on the LCSTs of the linear polymers was investigated. The LCST decreased with increases in the hydrophobic monomer N‐tert‐butylacrylamide, polymer concentration, and ionic strength. The phase transition became sharp when the polymer concentration and ionic strength increased. Meanwhile, the crosslinked hydrogels were prepared with the same recipe used for the linear terpolymers, but a crosslinker was added to the reaction system. The swelling ratios of the hydrogels at various temperatures and salt solutions were determined. The hydrogels possessed both high swelling ratios and thermosensitivity. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007 相似文献
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本文以全氟羧酸离子交换膜为支撑体、乙二胺(EDA)为活性络合剂、制备促进传质膜。在常用的工业条件下,测定了纯CO_2以及CO_2/N_2二元混合物在该膜内的渗透通量。实测结果表明,此膜对CO_2的促进因子可达13.8,而对CO_2/N_2的分离因子高达316。本文假设促进传质过程的控制步骤为气体在膜相的扩散,据此导出了相应的机理模型,该模型与实测结果吻合良好。 相似文献
56.
本文通过不混溶温度的确定,分相玻璃沥滤速率的测定以及NMR定量分析,研究了P_2O_6对Na_2O-B_2O_3-SiO_2系统玻璃结构和沥滤性质的影响。结果表明,P_2O_5在很大程度上促进钠硼硅分相玻璃的沥滤并非压抑“硼反常”所致,而是由以下三种因素综合作用的结果:(1)P_2O_5促进了钠硼硅玻璃的分相,使连通富硅相骨架尺寸增大;(2)P_2O_5的加入使富硅相骨架间隙中沉积的SiO_2量减少,减小了可溶相扩散阻力;(3)P_2O_5也使可溶相的溶解速率加快。 相似文献
57.
Matthias Berger Manfred P. Schnelder 《Journal of the American Oil Chemists' Society》1992,69(10):961-965
Regioisomerically pure 1(3)-rac-monoacylglycerols are conveniently prepared in high yields (>75%) and in multigram quantities by enzymatic esterification
of glycerol in the presence of various lipases(Chromobacterium viscosum, Rhizopus delemar, Rhizomucor miehei) with a variety of different acyl donors, such as free fatty acids, fatty acid alkyl esters, vinyl esters and triacylglycerols,
as well as natural fats and oils. All reactions are carried out in aprotic organic solvents with low water content, namelyn-hexane, diethyl ether, tBuOMe or mixtures of these solvents. Essential for the success of these transformations were the
following two factors. First, the creation of an artificial interphase between the solvent-immiscible hydrophilic glycerol
and the hydrophobic reaction medium by its adsorption onto a solid support. Second, a facile system for the separation of
the desired monoacylglycerol from the reaction mixture, coupled with the continuous recycling of acyl donor and undesirable
by-products. 相似文献
58.
在核电站安全级DCS设计中,为提高系统的可靠性,需保证安全级电气设备和电路之间的有效隔离,为了实现电气设备和电路的隔离,核安全相关法规标准提出了实体分隔、电气隔离等设计手段。本文通过对核电站安全级DCS隔离相关法规标准的分析,得出了电气设备和电路隔离的设计要求,提出了设计过程中应采取的方法和措施,并在此基础上给出了具体的实体分隔和电气隔离工程实现方案。该方案的工程实施结果可实现安全级DCS电气设备和电路的独立性要求,有效提高系统的可靠性,为系统的稳定运行提供重要保证和支持。 相似文献
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