Effects of Surfactant on Solubility and Microbial Conversion of Steroid

Enhancing the dispersion and dissolution of substrate particles in substrate water suspension is a feasible way to improve steroid bioconversion. The aim of the present study is to investigate the effects of applying surfactant to microbial conversion system on the dispersion, solubilization and in turn bioconversion of steroid substrate. The model system is hydroxylation of substrate 19α- 17α-epoxy- 4-pregnene- 3.2It-dine by microbial enzymes from Rhizopus nigricanl. The results show that the presence of substrate leads to an increase in critical micelle concentration （ CMC） of surfactant PSE compared with the normal CMC of PSE in aqueous solution. The grinding time during substrate suspension preparation affects the substrate aqueous solubility differently with the varied surfactant concentrations while barely making any difference in substrate solubility in the absence of surfactant. The properly prolonged grinding time can make up for the loss in substrate solubility arising from the reduction in surfactant concentration. The surfactant complexes composed of surfactants PSE and MGE at appropriate ratios are screened out with orthodoxy experiment method. the interaction between PSE and MGE exerts the most prominent effects on substrate bioconversion, and the surfactant complexes show more beneficial effects on steroid bioconversion than the surfactant PSE used alone.     

浊点萃取法用于模拟染料废水脱色研究

基于表面活性剂的浊点现象所建立的浊点萃取是一种绿色环保的萃取方法．本文选用非离子表面活性剂TX-114作浊点萃取剂,研究了由酸性大红与活性紫构成的单元和二元混合染料模拟有色废水的萃取脱色过程,讨论了表面活性剂浓度、染料浓度、盐浓度、平衡温度、平衡时间等因素对萃取效率的影响．结果表明,提高表面活性剂浓度、盐浓度有利于提高萃取效率,而染料浓度增加则使萃取效率略有下降．在由活性紫和酸性大红构成的单元和二元混合染料体系中,酸性大红的萃取脱除率明显较活性紫高,混合染料体系的萃取脱色行为与单染料体系的脱色行为相近．     

水/有机两相体系中苯甲醛与苯乙酮缩合反应的研究

合成了3种季铵盐型阳离子表面活性荆(C16H33)2N(CH3)2Br(双十六烷基二甲基溴化铵),C16H33,NC33H45(CH3)2Br(二十二烷基十六烷基二甲基溴化铵),C16H33NC12H25(CH3)2Br(十六烷基十二烷基二甲基溴化铵),并考察了其对水/有机两相体系中苯甲醛与苯乙酮Aldol缩合反应性能的影响.结果显示,含有两条疏水长链的阳离子表面活性剂对水/有机两相体系中苯甲醛与苯乙酮Aldol缩合反应具有明显的加速作用,其催化活性明显高于其它类型的表面活性剂;结果还显示,阳离子表面活性剂分子中疏水碳链的数目增加、疏水碳链的增长均有利于Aldol缩合反应.     

反相胶束法制备半导体CdS纳米线

在环已烷-表面活性剂C12E9-水溶液-正戊醇四元反相胶束体系中,利用表面活性剂作为控制合成的软模板,在温和的反应条件下,制备出平均直径为50nm、长度大于1.82μ的纳米线,并利用电子透射显微镜(TEM)和X射线衍射仪对产物的形貌和结构进行了表征,探讨了初步的合成机理.     

Enhanced degradation of carbon tetrachloride by surfactant-modified zero-valent iron

Sorption of carbon tetrachloride （CT） by zero-valent iron （ZVI） is the rate-limiting step in the degradation of CT, so the sorption capacity of ZVl is of great importance. This experiment was aimed at enhancing the sorption of CT by ZVI and the degradation rate of CT by modification of surfactants. This study showed that ZVI modified by cationic surfactants has favorable synergistic effect on the degradation of CT. The CT degradation rate of ZVI modified by cetyl pyridinium bromide （CPB） was higher than that of the unmodified ZVI by 130%, and the CT degradation rate of ZVI modified by cetyl trimethyl ammonium bromide （CTAB） was higher than that of the unmodified ZVI by 81%. This study also showed that the best degradation effect is obtained at the near critical micelle concentrations （CMC） and that high loaded cationic surfactant does not have good synergistic effect on the degradation due to its hydrophilicity and the block in surface reduction sites. Furthermore degradation of CT by ZVI modified by nonionic surfactant has not positive effect on the degradation as the ionic surfactant and the ZVI modified by anionic surfactant has hardly any obvious effects on the degradation.     

用吸收光谱法研究甲苯胺蓝水溶液的聚合状态及其影响因素

本文通过光谱法研究了生物染料试剂甲苯胺蓝（ＴＢ）在水溶液中的聚集状态,及其表面活性剂十二烷基硫酸钠（ＳＬＳ）、无机盐ＮａＣｌ对其聚集状态的影响。通过对在不同条件下甲苯胺蓝吸光度的分析,得出如下结论：ＮａＣｌ可使甲苯胺蓝（ＴＢ）的双聚体解聚;表面活性剂对甲苯胺蓝的聚集状态有很大的影响     

常用洗衣粉中表面活性剂含量及去污能力的测定

采用盐酸对甲苯胺法测定日常生活中常用的5种洗衣粉中表面活性剂十二烷基苯磺酸钠的含量及去污能力,结果表明可以采用本方法进行洗衣粉中表面活性剂十二烷基苯磺酸钠含量的测定。同时也说明了洗衣粉中表面活性剂含量适度高些,去污效果就越好。     

SDS浓度对乙烯水合物生成的影响研究

实验研究表明,表面活性剂胶束溶液可缩短乙烯水合物生成的诱导时间,加快水合物的形成,提高乙烯水合物的储气量。在水合物形成体系实验中,添加了阴离子表面活性剂(十二烷基硫酸钠)。结果发现,乙烯气体水合物在无搅拌(即静止)的系统中可快速形成,而且极大地提高了水合物的储气能力。对乙烯水合物储气而言,十二烷基硫酸钠溶液的浓度存在一个较适宜浓度800 mg/L,使水合物的储气量接近理论最大值135标准体积/体积。     

表面活性剂对复合电沉积法制备纳米碳管复合镀层的影响

采用复合电沉积法制备纳米碳管复合镀层,在控制实验基本工艺参数不变的条件下,通过加入不同的表面活性剂进行电镀,测量纳米碳管的质量占所得镀层总质量的百分比。经过分析后可以得到:阳离子表面活性剂更有利于制备纳米碳管复合镀层的电沉积;而阴离子表面活性剂以及非离子表面活性剂则不利于制备纳米碳管复合镀层的电沉积。     

表面活性剂的应用

从表面活性剂的应用原理出发，具体阐述了表面活性剂在工业、农业、日用品三个方面的应用，同时也对表面活性剂的发展趋势作了展望。     

三次采油用表面活性剂的合成和应用

三次采油(EOR)成为一种在一、二次采油之后有效提高采油率的重要技术，而表面活性剂在三次采油中的重要性越来越明显，其中表面活性剂驱和三元复合驱(ASP，即碱—表面活性剂—聚合物复合驱)则是具有发展潜力的三次采油技术。本主要介绍和概述了三次采油用表面活性剂的制备、性能、应用特点及其发展前景。     

Electrochemical Oscillations Induced by Surfactants

HeZhanbopointedout[1] thatsurfactantscanbeusedtomakenewchemicaloscillatorsinaqueoussolution ,suchasbromateoscillator[2 ] andpermanganateoscillator[3] .Untilnow ,however,thereisnotanyelectrochemicaloscillatorre latedwithsurfactant.　　Anelectrochemicaloscillatorisoneofthefirstdisco veriesofchemicaloscillators .Todayhundredsofarticleshavebeenpublished[4— 6 ] aboutelectrochemicaloscillators.Theyprovidematerialstoenrichmaturetheoriesandmecha nisms[7— 8] .InourexperimentsweusedaDaniellcellasele…     

Lung surfactant

Lung surfactant, a lipo-protein complex, is a highly surface-active material found in the fluid lining the air-liquid interface of the alveolar surface. Surfactant plays a dual function of preventing alveolar collapse during breathing cycle and protection of the lungs from injuries and infections caused by foreign bodies and pathogens. Varying degrees of structure-function abnormalities of surfactant have been associated with obstructive lung diseases, respiratory infections, respiratory distress syndromes, interstitial lung diseases, pulmonary alveolar proteinosis, cardiopulmonary bypass surgery and smoking. For some pulmonary conditions, especially respiratory distress syndrome, surfactant therapy is on the horizon.     

阴/阳离子表面活性剂混合体系性能研究

考察阴离子表面活性剂十二烷基硫酸钠(SDS)和阳离子表面活性剂十六烷基三甲基溴化铵(CTAB)混合体系的表面张力和乳化能力,并研究无机盐对混合体系性能的影响。实验结果显示,当m(SDS):m(CTAB)为8:2时,表面张力低至29.25mN·m-1,表现出较强的表面活性,且无机盐有降低表面张力的作用。表面活性剂混合体系对煤油具有较好的乳化能力。     

表面活性剂的HLB与其化学结构的关系

通过分析表面活性剂的化学结构与HLB值之间的关系，引用戴维斯的HLB基数，对决定表面活性剂性质的关键因素HLB进行了讨论，为表面活性剂的研究、产品开发、实际生产、综合应用提供了重要的参考数据．     

表面活性剂在光度分析中应用的新进展

本文简略回顾了我国近五年来表面活性剂在光度分析中应用的新进展,介绍了表面活性剂在光度分析中一些新方法和新体系.通过对五种表面活性剂体系的介绍对表面活性剂在光度分析中应用的发展状况和趋势有个了解.     

Gemini (dimeric) surfactants

A gemini surfactant (GS) consists of two conventional surfactant molecules chemically bonded together by a spacer. The two terminal hydrocarbon tails can be short or long; the two polar head groups can be cationic, anionic or nonionic; the spacer can be short or long, flexible or rigid. The GS need not be symmetrically disposed about the center of the spacer. GS can self-assemble at much lower concentrations and are superior in surface activity as compared to conventional surfactants. GS are very attractive for catalysis and adsorption applications, new synthetic vectors for gene transfection, analytical separations, solubilization processes, nanoscale technology, biotechnology, enhanced oil recovery and as paint additives.     

Application of reactive acrylate microgels in water-base coatings

Reactive acrylate microgels with different reactive groups such as carboxyl, hydroxide groups had excellent prop-erties such as quick-dry, low viscosity, high adhesion and hardness, which made them extensively used in preparing paints or in coating-modification. Reactive acrylate microgels were prepared by emulsion co-polymerization with zwitterions surfactant, anionic surfactant and nonionic surfactant as co-emulsifier. The water-base baking paints made from reactive acrylate micro-gels and melamine-formaldehyde resin had excellent combination properties. The aluminium powder can be well-dispersed in the paints. The influences of monomer components on the properties of the water-base baking paints were discussed in this paper. And the baking paints were also compared with the marketing solvent acrylate baking paints. It was found that the water-base acrylate amino baking paints had better combination properties than the organic solvent acrylate baking paints, which means that the water-base baking paints had a bright marketing future.     

以山苍籽核仁油为原料合成表面活性剂研究进展

本文综述了以山苍籽核仁油为原料合成羧酸盐、十二腈、烷醇酰胺、N-月桂酰基乙二胺三乙酸和含1,3-二氧六环的可断裂(降解)等环境友好的表面活性剂,山苍籽核仁油作为一种具有可再生资源优势的优良表面活性剂原料正被广泛用于生产中,有着广泛的开发前景。     

AOT/异辛烷反胶束体系制备CdTe量子点的研究

采用反胶束法制备CdTe量子点。反胶束体系由CdTe前驱体、AOT（丁二酸二异辛酯磺酸钠）、异辛烷组成;CdTe前驱体在水相中以巯基丙酸为稳定剂、按nCd2＋：nHTe-：nMPA=3：1：6、pH=9.8的条件合成。考察了反胶束体系中ω（ω=[水]/[表面活性剂]）、表面活性剂浓度对合成CdTe量子点的光学性质的影响。试验表明：当AOT的浓度为0.06g.mL-1时,改变ω能合成不同粒径的CdTe量子点,ω从7增加到13荧光发射光谱位移117.2nm。