乳状液膜用表面活性剂研究进展

综述了液膜用表面活性剂筛选、研制及其性能研究进展,进一步强调了研制性能优良的液膜专用表面活性剂对液膜技术工业化的重要意义。     

On the Applicability of the Regular Solution Theory to Multicomponent Systems

The critical micelle concentration (CMC) of aqueous mixtures of decyl- (C₁₀TAB), dodecyl- (C₁₂TAB), and tetradecyl trimethyl ammonium (C₁₄TAB) bromides has been studied in the complete triangular diagram. The results have been analyzed on the basis of the multicomponent regular solution theory for mixed micelles (MRST). It has been found that the mixtures of both, two or three components, contrary to the MRST theory assumptions, have a nonideal behavior. Both the experimental CMC, (CMC _ijk )_exp, and that computed with the MRST, (CMC _ijk )_calc), were lower than the ideal one, (CMC _ijk )_id, indicating an attractive interaction. Moreover, in the majority of the triangular diagram (CMC _ijk )_exp differs significantly from (CMC _ijk )_calc. This suggests that the assumption in the MRST that the interaction among the three different homologue molecules in the mixed micelle computed using the binary regular solution theory interaction parameters obtained from binary mixtures may be an oversimplification. This has been reinforced by analysis of the intramicellar activity coefficients of components, indicating differences in the surrounding of the component molecules when they are in bi- or tricomponent micelles. The excess free energy of micellization in three-component systems indicates that the more stable mixed micelles are those having an excess of the shorter components (C₁₀TAB–C₁₂TAB) and <50 % of the longer one (C₁₄TAB). Furthermore, the common statement that mixtures of homologue surfactants are ideal is not supported by this work.     

Determination of the molecular orientation in the polymeric liquid crystalline systems by low frequency Raman spectroscopy

Anisotropic polymer composites with fixed, oriented liquid crystalline organisation prepared by in situ photopolymerisation of acrylic or methacrylic acids in several cellulose derivatives were investigated by low frequency Raman scattering. The results were interpreted basing on a model of non-continuous structure of polymer glasses. The Raman investigations have shown that the macromolecules of the non-mesogenic (acrylic) component are oriented in the anisotropic composites, and that the orientation of the polyacrylic chains is more pronounced in the composites with higher concentration of the liquid crystalline cellulose derivative. It was found, that the interactions between the components play a crucial role in the formation of the composites (template-like photopolymerisation) and they determine their supramolecular structure. The liquid crystalline cellulose derivatives able to form hydrogen bonds play a role of specific cross-linking agents, while the cellulose derivatives with aliphatic side chains work as plasticisers.     

Approximate theoretical solution for the Sherwood number of oscillating bubbles at different Reynolds numbers

In this paper a theoretical approach to the effect of bubble oscillations on the mass transfer rates has been carried out to get a better understanding of the effect of bubble oscillations in multiphase gas–liquid contactors. The perturbation method has been used to approximate the velocity profile surrounding the bubbles while they oscillate. The shape of the oscillating bubble was modelled taking into account the effect of the liquid viscosity on bubble oscillation frequency and amplitude. The modelled shapes match the photographs of bubbles oscillating in liquids with different viscosities. As a result, new approximate theoretical models for the Sherwood number in viscous fluids at different flow regimes have been proposed. The models extend the work already available in the literature for mass transfer rates from oscillating bubbles in inviscid fluids and provides good results in predicting the Sherwood number at high and moderate Reynolds numbers, the preferred regimes in many industrial operations where, as a result of the hydrodynamics processes involving the bubbles. Their oscillations do not completely decay.     

A new technique for the measurement of ternary molecular diffusion coefficients in liquid systems

A double Savart plate birefringent interferometer was used to study the diffusional behavior of the ternary system. Acetone (1) – Benzene (2) – Methanol (3). The ternary diffusion coefficients were measured at 9 composition points covering the entire ternary diagram. The binaries forming the borders of the ternary diagram were also studied. The ternary diffusion coefficients at one composition point of the ternary system Actone (1) – Benzene (2) – Carbon tetrachloride (3) were measured and compared with previously reported data of Cullinan and Toor⁽¹⁸⁾, obtained by diaphragm cell method. Validity of the birefringent interferometric measurements when applied to the ternary liquid systems was confirmed through this comparison.     

液膜用系列高分子表面活性剂LMS-3和LMA-1的性能研究

对液膜用系列高分子表面活性剂ＬＭＳ ３和ＬＭＡ １的性能进行了研究。实验结果表明：由它们制成的液膜３０ｍｉｎ时破损率均低于０５％,２０ｍｉｎ时ＬＭＳ ３和ＬＭＡ １的溶胀率分别为２５０％和５０％,明显优于常用市售产品兰 １１３Ａ等。采用ＬＭＳ ３—ＬＭＡ １混合表面活性剂体系用于稀土提取,可使稀土的迁移率和富集倍数同时提高,具有较大的实用价值。     

Thermosensitive molecular imprinted polymer monolith for the selective recognition of quercetin

The thermoresponsive-molecular imprinted polymer (MIP) monolith with the ability of molecular recognition for quercetin was prepared. The smart monolith was synthesized using 2-acrylamide-2-methyl-propanesulfonic acid and N-isopropylacrylamide as temperature responsive functional monomers, respectively. It was observed that thermoresponsive-MIP₁ monolith had uniform porosity structure. Thermoresponsive-MIP₁ monolith displayed a stronger interaction with the imprint molecule by desorbing cyclic voltammetry. The chromatographic peak shape and recognition efficiency of thermoresponsive-MIP monolith was improved by elevated temperature. The thermoresponsive-MIP₁ monolith provided a great potential application in high-performance liquid chromatography system for recognizing quercetin with a short time by controlling the column temperature.     

采用新型生料质量控制系统取代生料均化库的可能性分析

本文论述了目前国内普遍采用的生料质量控制系统存在的主要问题，介绍了一些国内尚未采用的新的生料质量控制系统的技术方案。同时就新控制技术方案中的前置式在线生料质量控制系统特点的分析，提出了新型干法生产线使用该系统，将使缩小或取消生料均化库成为可能。     

A convenient method for the determination of molecular weight cut-off of ultrafiltration membranes

With the rapid increase of water contamination,membrane separation technology and their corresponding molecular weight cut-off (MWCO) evaluation method become more necessary.In this study,Panax notoginseng saponins was used as a new standard marker to determinate ultrafiltration (UF) membrane MWCOs,series of Millipore membranes were selected as control group to analyze and calculate the relationship between retention rate and MWCOs with exponential or logarithmic equation.A new and convenient method was provided for determining the membrane MWCO by modeling analysis retention rate with MWCOs,and the regression coefficients ≥0.990.The feasibility and practicability of established method was verified by different manufactures' membrane and dextrans.In the detection progress,as the main ingredient of Panax notoginseng saponins,Notoginsenoside R1,Ginsenoside Rg1,Ginsenoside Rb1and Ginsenoside Rd with different surface activity,the MWCO range of UF membranes can be divided into two zones mainly due to the retention rate difference among Notoginsenoside R1,Ginsenoside Rg1,Ginsenoside Rb1 and Ginsenoside Rd.Zone Ⅰ,1000-10000;and Zone Ⅱ,10000-100000.Thus,the new method would be helpful to improve the applicability of UF membrane in separation technology.     

运城盐湖卤水去除有机物工艺研究

运城盐湖卤水中含有的有机物和泥沙对以盐湖卤水为原料的无机盐产品质量有很大影响。以去除盐湖卤水中的有机物为主要目的,对混凝法、膜过滤法、混凝-膜过滤法等水处理方法进行试验对比,得出运城盐湖卤水先采用聚合硫酸铝（PAS）和氢氧化钠絮凝沉降去除有机物后,再经分子切割量为1000的超滤膜过滤的工艺是最为理想的。混凝-膜过滤工艺处理后的卤水有机物大大降低,且无机离子几乎无损失,是目前处理盐湖卤水中有机物首选的工艺路线,对生产厂卤水处理具有一定的参考作用。     

On the combination of different transport mechanisms for the simulation of steady-state mass transfer through composite systems using permeation through stainless steel supported silicalite-1 membranes as a model system

A method to calculate the steady-state multicomponent mass transfer in heterogeneous structures is presented. For this, different transport mechanisms represent different regions inside the composite system. The solving scheme allows the calculation of the molar flow rates along the different transport pathways and the estimation of unknown transport parameters based on experimental data.

The steady-state mass transfer of hydrogen and sulfur hexafluoride through a sinter metal supported MFI zeolite membrane is examined as a model system. The support is simulated using the dusty gas model, the molecules passing the zeolite layer may follow transport mechanisms like Knudsen diffusion, surface diffusion or activated gas diffusion. The configuration used, with data from single gas experiments, can predict the binary system only at high temperatures. The problems arising at low temperatures are due to the oversimplified assumption that adsorbed and desorbed molecules do not interact on their way through the MFI zeolite micropores.

However, because of the modular structure of the approach, it can be easily extended to more advanced transport models to account for interactions between the different molecules. And the method can be applied equally well to other systems, such as palladium composite membranes or membranes with catalytic activity.     

Introducing a new parameter for evaluating the degree of integration in cryogenic liquid recovery processes

Supplying the required refrigeration is one of the most important parameters in design of cryogenic liquid recovery processes and different configurations have been introduced in order to gain higher liquid recoveries or minimum total cost. However, due to the advantages and disadvantages of current invented configurations and changeable operating conditions of such processes and the different prices of the products and operating costs, selection of a configuration as the best one is not easy. In this work a new parameter for evaluating the degree of integration of such processes is introduced. This parameter can evaluate the degree of integration based on the recovered refrigeration from the process streams against the required refrigeration which is gained by different sources. The exergy concept was used in order to calculate the Integration Degree (IDG). IDG was defined for two kinds of processes; with and without external refrigeration. The results showed that the kind of configuration is a basic variable which can affect the IDG significantly, and influences of the other parameters are not significant in comparison. Consequently it can be said that with increasing IDG the process performance and integrity of the process increase and it can be used in optimization problems.     

On the possibility of using embedded electrodes for the measurement of dielectric properties in organic coatings

The present paper discusses the electric field distribution when an electric field is applied between two sensing electrodes embedded in an organic coating applied on metallic substrate. The results show that current lines tend to short-circuit throughout the metallic substrate and hence the measured impedance tends to approach that of the volume located below the electrodes plus the interfacial impedance. The results obtained from the numerical model have been verified by experimental measurements on organic coatings.     

Application of the seed-film method for the preparation of structured molecular sieve catalysts

The seed-film method has been applied for the preparation of various materials of potential interest as structured molecular sieve catalysts. The method has proven to be very flexible and allows for the reproducible preparation of a number of molecular sieve–substrate combinations as well as the control of the materials’ properties of importance in catalytic applications such as zeolite loading, film thickness, film density and crystal orientation. The preparation of thin molecular sieve films on ceramic foams, -alumina pellets and porous alumina supports as well as various metal surfaces is described. The preparation of zoned coatings with a compositional gradient is also discussed.     

Interaction of cyclodextrins with side chains of water soluble polymers: A simple model for biological molecular recognition and its utilization for stimuli-responsive systems

This article demonstrates that the interaction of cyclodextrins (CDs) with side chains of water soluble polymers is useful not only as simple models for biological molecular recognition but also as building blocks in nanotechnological applications. In the interaction of CDs with polymer side chains, the selectivity of CDs was enhanced by the steric effect of the polymer main chain and by interaction at multi-sites (i.e., collectivity). Utilizing the interaction of CDs with polymer side chains, stimuli-responsive systems were constructed from simple components.     

Synthesis of a new cationic surfactant for the alkaline hydrolysis of solvent‐pretreated polyester fabrics

The synthesis of a cationic surfactant was based on diethanolamine and alkyl halides such as cetyl bromide with epichlorohydrin as a quaternizing agent. It was characterized by the elemental microanalysis of nitrogen and chloride and infrared spectroscopy. Polyester (PET) crepe fabric was pretreated with a series of solvents, including tetrachloroethane and tetrachloroethylene, at 25, 50, and 100°C. Untreated and solvent‐pretreated PET fabric was hydrolyzed with 8 g/L NaOH at 100°C in the absence and presence of a cationic surfactant as a catalyst, and the weight loss was determined. The effects of solvent pretreatment on alkaline hydrolysis and PET dyeing were also examined. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 85: 1652–1660, 2002.     

An experimental method for measuring the spreading velocity of surface active substances on thin films of liquid substrate

This paper reports the development of a new experimental method suitable for the determination of the spreading velocity of surface active substances on a thin film of liquid substrate over a solid surface. Previous research showed that when oil and surfactants spread on the surface of a deep body of water, the spreading velocity is usually quite high, being in the range of several tens of centimeters per second. However, the spreading velocities of these substances on a thin water film are much slower. This is because that the spreading of an oil or a surfactant on water surface is not just a two dimension phenomenon, but a phenomenon involving the movement of water in a small depth below the surface. An additional process impeding oil or surfactant spreading in this situation is the interaction of the spreading molecules with the liquid/soild interface underneath water surface. The experimental method developed in this work uses a Wilhelmy balance to monitor the average spreading velocity of surface active substances on a thin water film over a porous solid substrate. The spreading of cellulose hydrophobization agents over wet paper web during the papermaking process is used as an example to demonstrate the capability of the method.     

500g/L噻虫嗪悬浮种衣剂配方研究

采用湿式超微粉碎加工工艺,以悬浮率、热贮稳定性、包衣均匀度和脱落率为标准,用流点法筛选合适的梳形高分子分散剂和类双子型分散剂,通过对不同润湿分散剂、成膜剂以及增稠稳定剂和防冻剂的筛选,得到了500 g/L噻虫嗪悬浮种衣剂的优化制剂配方为40%噻虫嗪,4%YUS-SC3,2%YUS-WG5,1%YUS-WG4,2%尿素,0.1%黄原胶,0.5%硅酸镁铝,0.1%消泡剂,水余量。经实验,其成膜性良好,脱落率<4%。包衣后的玉米种子,其发芽率97%,种衣剂对种子发芽率的影响<1%。     

Catalytic behavior of La–Sr–Ce–Fe–O mixed oxidic/perovskitic systems for the NO+CO and NO+CH4+O2 (lean-NOx) reactions

Mixed oxides of the general formula La_0.5Sr_xCe_yFeO_z were prepared by using the nitrate method and characterized by XRD and Mössbauer techniques. The crystal phases detected were perovskites LaFeO₃ and SrFeO_3−x and oxides -Fe₂O₃ and CeO₂ depending on x and y values. The low surface area ceramic materials have been tested for the NO+CO and NO+CH₄+O₂ (“lean-NO_x”) reactions in the temperature range 250–550°C. A noticeable enhancement in NO conversion was achieved by the substitution of La³⁺ cation at A-site with divalent Sr⁺² and tetravalent Ce⁺⁴ cations. Comparison of the activity of the present and other perovskite-type materials has pointed out that the ability of the La_0.5Sr_xCe_yFeO_z materials to reduce NO by CO or by CH₄ under “lean-NO_x” conditions is very satisfying. In particular, for the NO+CO reaction estimation of turnover frequencies (TOFs, s⁻¹) at 300°C (based on NO chemisorption) revealed values comparable to Rh/-Al₂O₃ catalyst. This is an important result considering the current tendency for replacing the very active but expensive Rh and Pt metals. It was found that there is a direct correlation between the percentage of crystal phases containing iron in La_0.5Sr_xCe_yFeO_z solids and their catalytic activity. O₂ TPD (temperature-programmed desorption) and NO TPD studies confirmed that the catalytic activity for both tested reactions is related to the defect positions in the lattice of the catalysts (e.g., oxygen vacancies, cationic defects). Additionally, a remarkable oscillatory behavior during O₂ TPD studies was observed for the La_0.5Sr_0.2Ce_0.3FeO_z and La_0.5Sr_0.5FeO_z solids.     

A new and rapid method for the evaluation of the liquid-solid contact resulting from liquid injection into a fluidized bed

Liquid feeds are injected into fluidized bed reactors such as fluid cokers, fluid catalytic crackers and gas-phase polymerization reactors. In these industrial processes, it is of crucial importance to optimize the contact between the injected liquid and the bed solids to minimize agglomeration, to ensure good reactor operability, and to allow reactions to proceed under minimum heat and mass transfer limitations in order to maximize the yields of valuable products. It has been shown [P. House, M. Saberian, C. Briens, F. Berruti, E. Chan, Injection of a liquid spray into a fluidized bed: particle-liquid mixing and impact on fluid coker yields. Industrial & Engineering Chemistry Research 43 (2004) 5663-5669., S. Bruhns, J. Werther, An investigation of the mechanism of liquid injection into fluidized beds. AIChE Journal 51 (2005) 766-775] that the nozzle technology and the operating conditions have a significant effect on the quality of the liquid-solid interaction resulting from the injection of gas-atomized liquid feed. The goal of this study was to develop a rapid and reliable experimental technique to assess the liquid-solid contact efficiency resulting from the injection of a liquid feed into a fluidized bed. Air-fluidized silica sand particles were first charged by triboelectrification as a result of their random collisions with the inner walls of the fluidized bed. Immediately after the injection of water through an aerated nozzle, the fluidization air was stopped and the wetted bed solids were allowed to settle. While the bed was defluidized, the triboelectric charges accumulated on the particles migrated to a grounded electrode through the low-resistance paths offered by the conductive liquid. A stronger electric current flowing through the electrode indicated that the liquid was more evenly distributed on the solid particles. The intensity of the current flowing through the electrode was, therefore, used to define a spray nozzle performance index. This technique was used to examine the effect of increasing the nozzle aeration, and, specifically, the gas-to-liquid mass ratio (G/L) through the nozzle on the liquid-solid contact efficiency. The results showed that changing the nozzle geometry can change how the contact efficiency between atomized liquid and fluidized solids varies with (G/L), especially at relatively high G/L ratios. A model of the time-evolution of the electric current generated during defluidization of the bed solids is also presented.