Extraction of anionic dyes with ionic liquid–nonionic surfactant aqueous two-phase system

The cloud point of nonionic surfactant (Triton X-114) in ionic liquid ([Bmim]Cl) aqueous solution exhibits as increase and then decrease and increase again with the increase of ionic liquid (IL) content, which is the origin of an IL–nonionic surfactant aqueous two-phase system. The nonionic surfactant-rich phase coexists with a high content of IL aqueous solution phase in the IL–nonionic surfactant aqueous two-phase system. The partitioning of various ionic dyes indicates that anionic species exhibit a high partitioning coefficient between the IL-rich phase and the nonionic surfactant-rich phase.     

氟碳表面活性剂在电子玻纤布表面处理中的应用

介绍了电子布的表面处理技术,用含/不含氟碳表面活性剂的偶联剂分别对电子玻纤布进行表面化学处理,对比了两种电子布的树脂浸透速度、半固化片的树脂含量和凝胶时间、半固化片层压工艺性能、制成的CCL的耐热可靠性。结果表明:用含氟碳表面活性剂的偶联剂处理后的电子玻纤布,应用性能得到显著提升。     

新型氟碳表面活性剂在灭火剂中的应用研究

氟碳表面活性剂因其高表面活性、高耐热稳定性、高化学稳定性以及带有氟元素的烃基同时具有憎水性和憎油性的特点在消防灭火领域广泛应用。对表面活性剂的结构、分类、特性、合成方法、在消防领域应用方面进行了系统阐述,最后进行了展望,以期对未来氟碳表面活性剂的研究有所帮助。     

湿化学法合成MoS_2微米颗粒及物性研究

MoS_2由于具有优异的物理和化学性质,作为功能材料被广泛地研究。采用水热法制备MoS_2微米颗粒,并通过添加表面活性剂、改变反应时间研究其对MoS_2微米颗粒结构和形貌的影响规律。实验得出如下实验结果:添加表面活性剂及退火处理可以提高MoS_2微米颗粒的纯度,降低其粒径尺寸,提高分子内部结构的有序性,但是表面活性剂随着反应时间的延长而活性有所降低。     

角质酶/表面活性剂体系对混合办公废纸的协同脱墨作用

角质酶能够水解可溶性酯、不溶性甘油三酯和各种聚酯，因此可以水解油墨中的连接料，有代替脂肪酶应用于废纸脱墨领域的潜能。利用角质酶和实验室复配得到的表面活性剂协同应用于混合办公废纸脱墨领域，探讨其脱墨效果和最优工艺，并与常用商业脂肪酶进行脱墨效果比较。结果表明，角质酶在酶用量10 U·g^-1，酶处理时间30 min，酶处理温度50℃，表面活性剂用量0.2%的条件下可以达到最优效果。与脂肪酶/表面活性剂以及单独用表面活性剂脱墨相比，角质酶脱墨后纸页的白度与油墨去除率更高，纸页的机械强度也较好。通过纸页性能的对比和扫描电镜（SEM）观察，角质酶的脱墨效果较脂肪酶更佳，角质酶/表面活性剂体系对混合办公废纸脱墨效果较好。     

Dispersed air flotation and foam fractionation for the recovery of microalgae in the production of biodiesel

Microalgae biomass has great potential for being used as feedstock for the sustainable production of biodiesel, as it is able to produce 7–31 times more oil than the top terrestrial crop. It is a green alternative to the currently utilized energy sources as it can reduce CO, CO₂ and hydrocarbon emissions. However, downstream processing costs for the dilute biomass are a major challenge. Foam flotation has been recently investigated for the recovery of microalgae cells from dilute liquid suspensions. A number of variables on the effectiveness of foam flotation for microalgae have been investigated, which include surfactant type and concentration, cell concentration, pH, hydrophobicity, time, growth stage, flow rate, ionic strength, alkalinity, temperature, bubble size, and column size. It appears to be a promising method for the recovery of algae for biofuel production, as a result of the high removal recoveries, good enrichment ratios, ability to process large volumes of biomass, and its ease of operation. However, literature on this subject is scarce, and there are research gaps that should be investigated including characterization of microalgae cells and impact on foam separation and the effect of surfactant as a treatment prior to lipid extraction.     

Extraction With Liquid Surfactant Membranes

Abstract

Liquid surfactant membranes, noted as a novel separation technique, have potential applications in many fields, especially in extractive metallurgy. High separation efficiency with the membranes can be achieved by using type I and type II facilitated transport mechanisms to maximize both the flux through the membranes and the capacity of the internal receiving phase for the diffusing species. Mass transfer models for both facilitated transport mechanisms are developed by taking into account the mass transfer and the reactions both inside and outside the emulsion globules, and perturbation solutions to the resulting nonlinear equations are presented. A Carrier Facilitated Transport Factor, defined as the ratio of the extraction rate constant for type II facilitation to that of type I facilitation, is proposed to account for the effect of carriers in the membrane on the extraction rate. Model predictions are in good agreement with the experimental data on batch extraction of acetic acid and auric chloride from their respective aqueous solutions.     

The structure of latherin,a surfactant allergen protein from horse sweat and saliva

Latherin is a highly surface-active allergen protein found in the sweat and saliva of horses and other equids. Its surfactant activity is intrinsic to the protein in its native form, and is manifest without associated lipids or glycosylation. Latherin probably functions as a wetting agent in evaporative cooling in horses, but it may also assist in mastication of fibrous food as well as inhibition of microbial biofilms. It is a member of the PLUNC family of proteins abundant in the oral cavity and saliva of mammals, one of which has also been shown to be a surfactant and capable of disrupting microbial biofilms. How these proteins work as surfactants while remaining soluble and cell membrane-compatible is not known. Nor have their structures previously been reported. We have used protein nuclear magnetic resonance spectroscopy to determine the conformation and dynamics of latherin in aqueous solution. The protein is a monomer in solution with a slightly curved cylindrical structure exhibiting a ‘super-roll’ motif comprising a four-stranded anti-parallel β-sheet and two opposing α-helices which twist along the long axis of the cylinder. One end of the molecule has prominent, flexible loops that contain a number of apolar amino acid side chains. This, together with previous biophysical observations, leads us to a plausible mechanism for surfactant activity in which the molecule is first localized to the non-polar interface via these loops, and then unfolds and flattens to expose its hydrophobic interior to the air or non-polar surface. Intrinsically surface-active proteins are relatively rare in nature, and this is the first structure of such a protein from mammals to be reported. Both its conformation and proposed method of action are different from other, non-mammalian surfactant proteins investigated so far.