应用马丁─侯状态方程计算含氨气体混合物的物性参数

本文将马丁—侯状态方程用于计算气体混合物的恒压热容、粘度和导热系数．含氨气体混合物的恒压热容为理想气体混合物热容与真实气体混合物剩余热容之和，根据剩余粘度法计算粘度，剩余导热系数法计算导热系数．三种压力，不同温度条件下气体混合物恒压热容、粘度和导热系数的计算结果表明：计算值与实验值相吻合．并分别拟合了合成氨生产三种工艺含氨气体混合物恒压热容、粘度、导热系数的计算式。     

强电解质混合物水溶液粘度的计算

本文介绍一种用离子贡献法计算强电解质水溶液粘度的通用模型。此模型不仅可以计算单一强电解质水溶液在各种温度和浓度下的粘度、而且还可以计算多种强电解质混合物在各种温度和浓度下的粘度。经过实践证明、精确度能满足工程设计的要求。     

含氨气体混合物的粘度和导热系数

本文讨论常压和加压下含氨气体混合物的粘度和导热系数的计算方法。常压下，改进的Ｓｕｔｈｅｒｌａｎｄ法计算粘度，Ｌｉｎｄｓａｙ－Ｂｒｏｍｌｅｙ法计算导热系数，其准确度较高。加压下，按Ｍ－Ｈ状态方程和Ｂ－Ｂ状态方程求得混合物的密度，采用剩余函数法计算了氨含量４．８％、１０．６％，压力９．９１ＭＰａ、１９．７２ＭＰａ、２９．５２ＭＰａ，不同温度下气体混合物的粘度和导热系数，计算结果与加压下含氨气体混合物粘度和导热系数的实验测定值相吻合。     

液体非电解质水溶液粘度的预测

在Teju-Rice液体混合物粘度模型的基础上,对常用的液体混合物粘度关联式进行了分析和比较;导出了适用于二元和多元非电解质水溶液的粘度模型;结合实际数据导出的水溶液二元作用参数的估算式可进行水溶液粘度的预测。用该模型计算了7个体系398个不同温度和组成的二元水溶液和4个体系189个不同温度和组成的三元水溶液的粘度,结果表明,计算值对实验数据的总平均相对偏差分别为6.848%和5.043%,本文水溶液粘度估算式的计算准确性优于Teju-Rice法。     

裙带菜吸附水溶液中镍离子的特性及吸附平衡模型

本文实验研究了裙带菜对废水中重金属镍离子的吸附特性和吸附平衡模型。实验表明裙带菜对镍离子的吸附能力最高达O．76mmol/g(干裙带菜)。在恒定pH条件下,Langmuir方程可用来描述吸附容量与平衡浓度的关系。但吸附容量受溶液pH值影响很大,在pH2．O～6．O范围内,pH值越低吸附量越小,pH在5.5～6.O时有较大吸附容量。竞争吸附模型可以很好地描述溶液中pH值和离子浓度对吸附的影响,可以预测再生条件。     

碳酸二苯酯在乙醇-碳酸二乙酯中固液平衡的测定与关联

采用激光法测定了碳酸二苯酯(DPC)在乙醇 碳酸二乙酯(DEC)混合溶剂中的溶解度。结果表明,在283.15～333.15 K下,碳酸二苯酯在混合溶剂中的溶解度随温度的升高而增大;相同温度下,溶解度随着乙醇浓度的增大而减小。进一步选用Wilson方程和λh方程拟合DPC的溶解度, 根据实验数据回归了模型参数,溶解度拟合值与实验值非常吻合,平均误差小于2.0%。计算表明Wilson方程对碳酸二苯酯-乙醇-碳酸二乙酯体系的计算精度更高些。     

间十五烷基酚在正庚烷中密度和粘度的测定和关联

实验测定了温度为283．15～308．15 K条件下间十五烷基酚与正庚烷形成的二元体系的密度和粘度。通过拟合,得到了准确的模型参数,同时计算了测定值和计算值之间的误差。结果证明,数据和模型拟合效果良好, VTF方程的标准方差是0．78％,数据和模型对于间十五烷基酚分离提纯的工程设计非常有用。     

液体非电解质水溶液粘度的关联

在Teju-Rice液体混合物模型的基础上,对常用的液体混合物粘度关联式进行了分析和比较,导出了适用于二元和多元水溶液的粘度模型。用该模型计算了6个体系388个不同温度和组成的三元水溶液的粘度,计算值对文献实验数据的总平均相对偏差分别为6.09%和5.54%,计算值准确性优于Teju-Rice模型。     

由虚拟粘度概念求无限稀释液相扩散系数

依据理论模型推导出由虚拟粘度概念估算无限稀释液相扩散系数的关系式.虚拟粘度可由混合物粘度确定,也可从纯物质的粘度估算.仅由纯物质粘度计算虚拟粘度,本文方程对50个扩散系数的估算误差为10.6%,而Wilke—Chang方程和Tyn-Calus方程的估算误差分别为22.9%和14.2%.     

有机物水溶液粘度的关联和预测

在Eyring的液体粘性流动模型的基础上,根据Sandler的水溶液过量自由焓溶质聚集模型,导出有机物水溶液的粘度模型。利用该模型方程参数与温度的关系,可预测低压下各种温度和不同组成的有机物水溶液的粘度。用该模型计算了7个体系442个不同温度和组成的二元水溶液和3个体系164个不同温度和组成的三元水溶液的粘度,计算值与实验值的总平均相对偏差分别为1.554%和2.588%,计算值与实验数据吻合很好。     

氯化铝及其碱式盐类水溶液的相对粘度测定

利用乌氏粘度计测定了氯化铝及其碱式盐类水溶液在３０１．１５Ｋ时的相对粘度。相对粘度满足Ｊｏｎｅｓ－Ｄｏｌｅ方程。Ｊｏｎｅｓ－Ｄｏｌｅ系数Ｂ值随盐类分子中氯离子减少而减小，且两者呈线性关系。     

Betaine·HCl-6EG-nNiCl2·6H2O低共熔离子液体的黏度和电导率

在常压下303~353 K和303~348 K温度范围分别测定了低共熔溶剂盐酸甜菜碱-乙二醇(Betaine·HCl-6EG)中加入不同浓度NiCl₂·6H₂O形成的Betaine·HCl-6EG-nNiCl₂·6H₂O低共熔离子液体的黏度和电导率,研究了温度、NiCl₂·6H₂O浓度对其黏度、电导率的影响规律。结果表明,在所研究的温度和NiCl₂·6H₂O浓度范围内低共熔离子液体Betaine·HCl-6EG-nNiCl₂·6H₂O都具有较低的黏度和良好的导电性。随着温度的升高,黏度减小,电导率增大,温度对黏度的影响更显著;黏度、电导率与温度的关系均可以用Arrhenius经验公式描述,由此计算得到其黏滞活化能和电导活化能。随着NiCl₂·6H₂O浓度的增加,黏滞活化能和电导活化能均会增大;NiCl₂·6H₂O的加入使得离子液体形成尺寸较大的络合离子,导电离子的有效浓度降低、离子半径增大,导致其电导率减小、黏度增大。     

MIGRATION AND DIFFUSION OF BINARY ELECTROLYTES UNDER A CONSTANT CURRENT II

The problem in title is analyzed for dilute solutions with no substantial intenonic effects and with the diffusivity and the electrophoretic mobility being related via the Nernst-Einslein equation. The case is considered of only the positive ion reacting at the electrodes, being produced at the anode and consumed at the cathode, With the electroneutrality condition as a first approximation, the equations for the average concentration and the electric field are decoupled and solved analytically. Then the deviation from electroneutrality is calculated in the second approximation via Poisson' s equation. The problem has a steady state if the current is smaller than a certain value. With this analysis and measurements of concentrations at different times, electrophoretic mobilities of the two ions can be calculated. The implications for interpreting measurements in microelectrophoresis and electrophoretic mass transport analysis are discussed     

MIGRATION AND DIFFUSION OF BINARY ELECTROLYTES UNDER A CONSTANT CURRENT II

The problem in title is analyzed for dilute solutions with no substantial intenonic effects and with the diffusivity and the electrophoretic mobility being related via the Nernst-Einslein equation. The case is considered of only the positive ion reacting at the electrodes, being produced at the anode and consumed at the cathode, With the electroneutrality condition as a first approximation, the equations for the average concentration and the electric field are decoupled and solved analytically. Then the deviation from electroneutrality is calculated in the second approximation via Poisson' s equation. The problem has a steady state if the current is smaller than a certain value. With this analysis and measurements of concentrations at different times, electrophoretic mobilities of the two ions can be calculated. The implications for interpreting measurements in microelectrophoresis and electrophoretic mass transport analysis are discussed     

EFFECT OF DISSOLVED INORGANIC SALTS ON THE VAPOR-LIQUID EQUILIBRIA AND ENTHALPY OF MIXING OF THE METHANOL-ETHYL ACETATE SYSTEM

The effect of three inorganic chloride salts, namely, sodium chloride, calcium chloride and zinc chloride on the vapor-liquid equilibria (VLE) and heat of mixing (h.o.m) of the methanol-ethyl acetate system has been investigated under the atmospheric conditions of 760 ± 3 mm Hg pressure. In the experimentation for VLE a Smith and Bonner type equilibrium still was used while in h.o.m. determination a calorimeter connected to a microprocessor-based control unit (MIPROC) which displays digitally the heat of mixing values in calories was employed. All the three salts dissolved to various concentration levels in the solvent mixture brought about a decrease in the azeotropic composition (expressed in terms of mole fraction of methanol) from 0.75 to values like 0.50, 0.37 and 0.18 depending upon the salt added and its concentration level. The salts sodium chloride and calcium chloride which are more soluble in methanol have been found to salt-in that component but with a peculiarity in that, in methanol-rich region the salting-in effect was substantial while in the methanol-lean region it is only marginal. The addition of salt zinc chloride which is more soluble in ethyl acetate results in an anomalous behaviour.

As for the salt effect on h.o.m., the addition of calcium chloride brought about a significant enhancement in the h.o.m values while the salts sodium chloride and zinc chloride (which could be added only to about 5% by weight concentration due to the experimental difficulties) entailed a decrease and lateral shift respectively in the h.o.m. values.

The VLE and h.o.m data which were found to be thermodynamically consistent have been correlated respectively by NRTL, Wilson and by a model similar to the Scatchard series type equation.     

反渗透过程的浓度极化及其传质系数测定

The relationship between osmotic pressure difference across the membrane and mass transfer coefficient is developed in this paper. On the basis of this relationship, a method for measuring mass transfer coefficient by using experimental data on reverse osmosis is established. Pitzer's equations are used to calculate osmotic pressure differences in order to assure accuracy of results. Under the conditions of constant operating pressure and bulk flow, mass transfer coefficient is scarcely affected by membrane structure, but decreases slightly with increasing feed concentration. The solute concentration in the polarization layer is calculated by using the measured values of mass transfer coefficient. Polarization layer concentration increases with augmentation in bulk concentration. However, their difference increases with increasing bulk concentration until a maximum difference is reached, and then decreases. Mass transfer coefficient increases with higher velocity of bulk flow. If mass transfer coefficient is so large that the ratio(PwΔπσ/k)becomes very small, polarization could be neglected.     

Viscosity of tetraethylammonium bromide solutions in N,N-dimethylformamide-water mixtures

The viscosity of tetraethylammonium bromide solutions in dimethylformamide-water mixtures have been determined at 25, 30 and 35°C. From this data, the B-coefficient of Jones-Dole equation have been calculated and are analysed in terms of structure making or structure breaking ability of the ions. Further, the activation parameters of viscous flow were obtained by means of the application of the transition-state theory. These values are studied in function of solvation and volume effects, in order to estimate the mechanism of the viscous flow.     

Anomalous dilute solution properties of segmented polydimethylsiloxane-polyurea copolymers in isopropyl alcohol

Preliminary characterization of amphiphilic segmented copolymers of polydimethylsiloxane and urea ‘hard blocks’ was conducted by measuring isopropyl alcohol (primarily) dilute solution viscosities via capillary viscometry. The traditional data analysis techniques, which provide for extrapolation of intrinsic viscosities from these experiments, revealed that increasing concentrations of polymer produced lower reduced viscosities rather than the expected higher values. A very approximate data fit reveals negative Huggins and Kraemer constants from these analyses, which are highly unusual. In a solvent such as DMF, a similar polymer having poly(tetramethylene oxide) and urea blocks and measured with identical conditions exhibited the expected behavior, showing increasing reduced viscosities over concentrations in the same range. However, the non-linearity of the data is suggestive of much more complex hydrodynamic, or supramolecular, interactions that are not clarified by the initial research.     

Preparation,structural elucidation,molecular weight determination,and molecular recognition of first‐ and second‐tier dendrimer molecules

1,3,5‐Triglyceratetriazine [first tier (G₁)] and tri(1,3,5‐triglycerate) triazine [second tier (G₂)] dendrimers were prepared with 1,3,5‐trichlorotriazine and sodium glycerate in a 1 : 3 mass ratio in an ethanolic medium.G₁ and G₂ were amorphous, white, solid substances. Their structures were elucidated with IR, ¹H‐NMR, and ¹³C‐NMR, and their thermal stability was studied with thermogravimetric analysis. The activation energy was calculated with the Freeman–Carroll model. Densities, viscosities, and surface tensions for 0.01–0.08 mol/kg aqueous solutions increased at 0.01 mol/kg for sodium glycerate, 1,3,5‐trichlorotriazine, 1,3,5‐triazine triglycerate chloride, G₁, and G₂. These values were measured at 298.15 K. The apparent molal volume, reduced viscosity, and inherent viscosity were calculated from the densities and viscosities, respectively. The data were regressed for the limiting densities, limiting apparent molal volumes, intrinsic viscosities, limiting inherent viscosities, and limiting surface tensions for solute–solvent interactions. The positive limiting apparent molal volume values were noted in the order of G₂ > 1,3,5‐triazine triglycerate chloride > G₁ > 1,3,5‐trichlorotriazine > sodium glycerate, with weaker hydrophilic intermolecular interactions of G₂. The higher intrinsic viscosity and limiting inherent viscosity values for G₂ implied stronger G₂–H₂O hydrophilic interactions, and the higher limiting apparent molal volume of G₂ indicated slightly higher dynamic conformational changes in comparison with G₁, with stronger structural activities. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Current–voltage behaviour of bipolar membranes in concentrated salt solutions investigated with chronopotentiometry

Chronopotentiometry is used as a tool to obtain detailed information on the transport behaviour of the bipolar membrane BP-1 in solutions of high sodium chloride concentration above the limiting current density. We discuss critically the interpretation of the observed transition times. The occurrence of two such polarization times for low to moderate current densities is explained by the membrane asymmetry: the two membrane layers of opposite charge in general have different transport properties such as co-ion concentration and diffusion coefficient. The reversible and irreversible contributions to the transmembrane potential can be distinguished which allows the bipolar membrane energy requirements to be addressed. The experiments indicate that the increased voltage drop across bipolar membranes observed with higher solution concentrations can be explained on the basis of stronger concentration gradients in the membrane layers. The gradients become stronger with increased current density, but here the ohmic resistance under steady state transport conditions (the transport resistance) contributes to the increasing electrical potential. The transport resistance decreases with increasing current density due to the ion-exchange of the salt counter ions with the water splitting products. The experiments show that bipolar membranes should be operated at low current densities and low concentrations to minimize energy requirements. These findings are in contrast to the high current densities required to reduce impurities in the produced acid and base.