十六烷基三甲基溴化铵在二氧化硅表面吸附的研究

十六烷基三甲基溴化铵在亲水二氧化硅表面的吸附呈现出两阶段的特点，在第一阶段对应单分子层吸附，而第二阶段对应双分子层吸附，用椭圆偏振法测出的十六烷基三甲基溴化镓在二氧化硅表面吸附层的厚度表明了这特性。     

Mechanism of micelle formation in sodium dodecyl sulfate and cetyltrimethylammonium bromide

pH changes as a function of concentration for sodium dodecyl sulfate (SDS) and cetyltrimethylammonium bromide (CTAB) were observed by addition of 1 N HCl and 1 N KOH. pH values increased up to the critical micellar concentration (CMC) for the SDS/HCl system and decreased for the CTAB/KOH system. In the SDS/HCl and CTAB/KOH systems, the micellar phase had a fixed composition and was homogeneous and monodisperse above the CMC. However, in the SDS/KOH and CTAB/HCl systems, pH values increased continuously and gradually below and above the CMC, and the properties of the micellar phase changed as a function of concentration, giving rise to inhomogeneity and polydispersity.     

Permeation of sodium dodecyl sulfate through polyaniline-modified cellulose acetate membranes

The preparation of polyaniline (PANi)-cellulose acetate (CA) blends by casting films from a suspension, is reported. Two membranes were prepared from different solvents, one with a homogeneous and the other a heterogeneous dispersion of PANi in CA matrices. The membranes were characterized by X-ray diffraction, SEM, DSC, and FTIR, and the results were compared with those obtained for pure CA and PANi films. The transport properties of water and sodium dodecyl sulfate (SDS) in membranes of the PANi-CA blends and of CA were analysed. The transport of SDS and water depends on both the bulk/polymer density and the PANi content. In the homogeneous blend, the interaction between SDS and the polymer plays an important role in the transport mechanism. An irreversible interaction is observed, which can be monitored by UV-vis spectroscopy. The spectra of homogeneous, highly transparent PANi-CA blends show a pronounced sensitivity to SDS concentration, with detection limits [SDS]≥0.1 mM for films with a PANi concentration of 0.05% w/v.     

Measurement of calcium ion suppression by protection of foam of sodium cetyl sulfate solutions

Summary Relative protection of various compounds against calcium salts was determined by a pour-foam test, using sodium cetyl sulfate as a foam-producing indicator. The sensitivity of the test corresponds to less than 2 p.p.m. of calcium salt. Some of the data are compared with similar tests, using sodium oleate as an indicator, and advantages of the cetyl sulfate test are noted. The test is discussed from the point of view of a competition for calcium ion by the cetyl sulfate anion to precipitate calcium cetyl sulfate and by the compound tested to precipitate a calcium salt or form complex calcium ions. On the basis of the equilibria involved an estimate is made of the approximate solubility of calcium cetyl sulfate in the salt solutions tested.     

Enhancing the electrochemical performance of lithium sulfur batteries using cetyl trimethylammonium bromide coated separator

Journal of Applied Electrochemistry - In this study, cetyltrimethylammonium bromide (CTAB)-modified separator is developed by using a simple and facile method for lithium–sulfur (Li–S)...     

十二烷基硫酸钠对聚乙烯吡咯烷酮水溶液黏度特性的影响

利用乌氏黏度计在(30±0.05)℃条件下研究了不同聚乙烯吡咯烷酮(PVP)质量浓度与不同十二烷基硫酸钠(SDS)浓度组合的复合溶液的黏度,观察到PVP-SDS溶液黏度曲线上存在双临界浓度c1和c2,表明在c1和c2之间SDS以束缚胶束形式簇集在PVP高分子链上;研究了不同"比簇集量"的PVP-SDS团簇溶液的比浓黏度特性,发现比浓黏度随PVP质量浓度降低反而显著增大,偏离了单纯PVP溶液而与典型的聚电解质聚丙烯酸钠(Na PAA)溶液相似;计算了PVP-SDS团簇中高分子链的均方末端距r2及其与单纯PVP类比的链相对扩张量k值,发现随着比簇集量[Г]增加k值增大。根据实验结果,将上述现象解释为由于带电的SDS束缚胶束簇集在PVP高分子链上,产生了"聚电解质效应",从而导致高分子链扩张。     

Two-phase aqueous systems of cetyltrimethylammonium bromide/sodium dodecyl sulfate with and without polyethylene glycol

Aqueous two-phase systems of cetyltrimethylammonium bromide and sodium dodecyl sulfate mixtures without and with polyethylene glycol (PEG) added have been studied at 313.15 K. The results have shown that PEG has a strong effect on the phase diagram of ATPS and microstructures of surfactants aggregates. The addition of PEG leads to the formation of bigger surfactant aggregates, which can be attributed to both the screening effect and the connection effect of PEG. All ATPS, especially those with PEG added, may have potential applications in separation and purification of biomaterials.     

细菌纤维素硫酸酯的制备及吸附Cu~(2+)的研究

以细菌纤维素为原料,合成细菌纤维素硫酸酯,用于吸附去除水中的Cu2+。采用红外光谱仪对细菌纤维素硫酸酯的结构进行了分析,探讨了反应时间、温度、H2SO4浓度等因素对交换容量的影响,在优化条件下交换容量为2.87mmol·g-1,并对其吸附Cu2+的性能进行了研究。结果表明,细菌纤维素硫酸酯对Cu2+有强的吸附能力,且易于再生。     

Influence of sodium dodecyl sulfate on the characteristics of bovine serum albumin solutions and foams

Results from surface tension measurements on mixed solutions of the protein bovine serum alburnin (BSA) and an anionic surfactant (SDS: sodium dodecyl sulfate) suggested that at an air-liquid interface, adsorption was affected by the protein-surfactant interaction and by the relative concentration of each component in solution. Two plateaus corresponding to the critical aggregation concentration (CAC) and the critical micelle concentration (CMC) of SDS, respectively, were observed in the surface tension isotherms of SDS in the presence of BSA. The CAC and CMC depended on the concentration of BSA. Effects of SDS concentration on the conformational changes of BSA were investigated by Fourier transform-Raman spectroscopy. The results showed that the contents of α-helix decreased while the contents of random coil increased. The presence of the anionic surfactant SDS had a negative influence on the way that proteins adsorb at an air-liquid interface, leading to the change of behavior of protein-stabilized film.     

柠檬酸钠对纳米碳酸钙结晶的影响

用石灰乳液碳酸化法制备纳米碳酸钙,在不添加任何添加剂的条件下制备出平均粒径为40 nm的立方状方解石型碳酸钙,以柠檬酸钠为添加剂,制备出最大长径比为9的链状方解石型碳酸钙。利用SEM,TEM和XRD分析手段,研究了柠檬酸钠及其加入量对碳酸钙产品颗粒形貌和结构的影响。柠檬酸钠用量为氢氧化钙质量的2%,进行碳酸化反应,在制得的长径比为9的链状碳酸钙悬浮液中,连续补加同质量分数的石灰乳,同时控制二氧化碳的通入速度,继续碳酸化,得到类似雪花状和链状两种形态同时存在的碳酸钙产品。     

Effects of pH and temperature on the sorption of sodium dodecyl sulfate by cellulose acetate/polyaniline blend membranes

Cellulose acetate/polyaniline (PANi) blends show a selective response to the presence of sodium dodecyl sulfate (SDS). Such detection can be monitored by visible absorption spectroscopy. In this article, we show how this is dependent on the pH and temperature. At pH 2, the redshift of the maximum absorbance wavelength of blend films is essentially dependent on hydrochloric acid; however, at pH 3, this effect clearly decreases, and at pH values between 4 and 6, the alteration of the blend color depends only on SDS. The selective detection of SDS is faster with a higher percentage of PANi in the blend. At 25°C, the mechanism of sorption is essentially Fickian for short times, but this changes at higher temperatures, and at temperatures of 40°C and higher, the sorption kinetics show an initial time lag in which no visible response from the blend to SDS is detected. The response rate of blends to SDS detection increases with the temperature and PANi content. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Influence of emulsifiers on film formation from cellulose acetate latexes experimental study of phase separation phenomena due to sodium dodecyl sulfate. I

Cellulose acetate membranes prepared from latexes containing sodium dodecyl sulfate as a stabilizer were found to undergo phase separation. This phenomenon was studied by different techniques including autoradiography, optical and scanning electron microscopy, mechanical testing, and liquid water permeation. The concentration of sodium dodecyl sulfate in the dry membranes was found essential in controlling their structure and properties, as well as the nature and amount of plasticizer incorporated in the latex system. The method of preparation and the drying duration were also relevant. Depending on whether films were produced by casting or spraying, tensile and permeation values exhibited quite different responses to variations of the sodium dodecyl sulfate content. In Paper II, a thermodynamic framework is proposed that accounts for the redistribution of sodium dodecyl sulfate into small islets, and thus for phase separation.     

十二烷基硫酸钠对膜蒸馏过程影响

膜蒸馏具有较低的操作压力、操作温度以及运行成本等优点，因此在水处理方面有广泛的应用前景。但是膜蒸馏过程中的膜润湿和膜污染现象仍然是阻碍其工业化应用的主要问题。表面活性剂作为一种能显著降低溶液表面张力、改变进料液性质的物质，对膜蒸馏造成的影响值得被研究。基于此，研究了在直接接触式膜蒸馏（DCMD）过程中表面活性剂对不同商业微孔疏水膜造成的影响，选用了一种常见的阴离子表面活性剂十二烷基硫酸钠(SDS)进行实验。结果表明，进料液中SDS浓度的上升会引起更为严重的膜润湿现象，并且所使用的三种商业膜中，双疏膜抗润湿性最强，而PVDF膜最弱。而当Ca²⁺大量存在于进料液中时，Ca²⁺与SDS的聚集降低了膜润湿的程度但其在膜表面的沉积造成了严重的膜污染。界面相互作用自由能的计算结果表明Ca²⁺/SDS与PVDF膜之间的吸引力最大、PTFE膜其次、双疏膜最小，这一结果与膜蒸馏过程中通量变化情况相符。     

石墨烯修饰微生物燃料电池降解十二烷基磺酸钠

以十二烷基磺酸钠为阳极电子供体,同时以石墨烯为催化剂对电极进行修饰。将修饰前后微生物燃料电池的产电性能和十二烷基磺酸钠的降解情况进行对比,经过修饰的电极装置产电效率明显增大,最大电压增加了1倍,并使十二烷基磺酸钠的降解率从49.85%提高到65.11%。这说明用石墨烯修饰后的微生物燃料电池在稳定产电的同时降解十二烷基磺酸钠是可行的,为废水中阴离子表面活性剂的去除提供了新的方法与研究方向。     

石墨烯修饰微生物燃料电池降解十二烷基磺酸钠

以十二烷基磺酸钠为阳极电子供体,同时以石墨烯为催化剂对电极进行修饰。将修饰前后微生物燃料电池的产电性能和十二烷基磺酸钠的降解情况进行对比,经过修饰的电极装置产电效率明显增大,最大电压增加了1倍,并使十二烷基磺酸钠的降解率从49.85%提高到65.11%。这说明用石墨烯修饰后的微生物燃料电池在稳定产电的同时降解十二烷基磺酸钠是可行的,为废水中阴离子表面活性剂的去除提供了新的方法与研究方向。     

Influence of phosphate and iron on the extent of calcium carbonate precipitation during anaerobic digestion

The extent to which calcium carbonate deposition in an anaerobic reactor can be reduced by adding inhibitors (phosphate and iron) of calcium carbonate crystal growth was investigated. At several concentrations of the additive, the extent of precipitation was assessed in continuous experiments with laboratory‐scale reactors. In the reactor, phosphate concentrations as low as 0.5–5 mg total‐P dm⁻³ were found to severely inhibit CaCO₃ precipitation. However, iron did not inhibit the deposition of CaCO₃, which was found to be due to the fact that iron, in contrast to phosphate, only inhibits the growth of calcite and not the formation of aragonite. The results led to the conclusion that only additives which inhibit the formation of both aragonite and calcite can be used as effective inhibitors during anaerobic digestion. A chemical equilibrium model was developed and shown to be a useful tool to calculate the extent of calcium carbonate deposition during anaerobic digestion provided the proper apparent solubility product of calcium carbonate can be estimated. © 1999 Society of Chemical Industry     

Influence of detergent builders on surface properties of sodium dodecyl sulfate solutions under dynamic and static conditions

The effects of various detergent builders on surface properties of sodium dodecyl sulfate (SDS) solutions have been investigated by measuring the equilibrium surface tension and hysteresis curves of surface pressure vs surface area under dynamic conditions. While the adsorbed layer of SDS under static conditions is in the liquid-expanded state, a two-dimensional phase transition of the adsorbed layer from liquid-expanded to condensed-film can be observed on compression at higher rates beyond the saturated adsorption. For the SDS solution containing excess NaCl (1×10⁻¹ M), the adsorbed layer of SDS is already in the condensed state under static condition due to a depression in the dissociation of SDS. It has been found that some polyelectrolytes, as well as conventional ionic builders, contribute to increasing the surface excess concentration of SDS together with promoting micelle formation and also to stabilizing the adsorbed layer of SDS. On the other hand, poly(vinyl alcohol) (PVA) as a nonionic polymer is adsorbed at the air-water interface in preference to SDS. In this case, the hysteresis of the dynamic surface behavior of the mixed solution can be attributed to the structural change of the adsorbed layer of PVA rather than SDS, which is different from the other ionic builders.     

Influence of ethanol addition on the modification of montmorillonite by hexadecyl trimethylammonium bromide

Although modification of montmorillonite (MMT) with cationic surfactants has been studied extensively, the influence of the reaction medium has not been investigated systematically. The present paper reports the influence of ethanol on the modification of MMT using hexadecyl trimethylammonium bromide (HDTMA-Br). Wide angle X-ray diffraction (WAXD) and thermogravimetric analysis (TGA) were used to characterize the organically modified montmorillonite (OMMT). The addition of ethanol had little influence on the cation exchange, but affected greatly on the intercalation of the surfactant ion pairs into the interlayer space when HDTMA exceed the cation exchange capacity (CEC) of MMT. The increase of the ethanol/water ratio increased the critical micelle concentration (CMC) of HDTMA-Br solution. The intercalation of HDTMA ion pairs proceeded when the HDTMA concentration was above the CMC. It was confirmed that both of basal spacing and organic fraction followed sigmoid functions for OMMT prepared with excess HDTMA-Br amount and various surfactant concentrations under different CMC.     

十二烷基硫酸钠干燥新技术的研究

在对十二烷基硫酸钠性能研究的基础上,采用新型复合式干燥设备对十二烷基硫酸钠干燥工艺进行了研究。研究结果表明,十二烷基硫酸化物在60℃～70℃下,中和到70%～75%后,预热到90℃～100℃,以1.0t/h～1.5t/h的流量进入复合式真空干燥器中进行干燥,干燥后的产品经孔板孔径为1mm～1.5mm的双螺杆挤出机造粒,钢带冷却可制得水含量低于2%的针状十二烷基硫酸钠。