Altering the wettability of bitumen-treated glass surfaces with ionic surfactants

The abilities of three ionic surfactants—sodium methylnaphthalene sulfonate (SMNS), sodium dodecyl sulfate (SDS), and cetyl trimethylammonium bromide (CTAB)—to alter the wettability of bitumen-treated glass surfaces was examined. Surface wettability was characterized by contact angles, and all measurements were carried out under alkaline conditions by having sodium carbonate (Na₂CO₃) dissolved in the aqueous phase. It was found that Na₂CO₃ alone could slightly increase the hydrophilcity of bitumen-treated glass surfaces. With surfactants added to the system, it was demonstrated that SMNS and SDS (both anionic surfactants) were much more effective in enhancing the water wettability of bitumen-treated glass in comparison to CTAB (a cationic surfactant). X-ray photoelectron spectroscopy (XPS) analyses were also conducted to determine the functional groups and relative mass concentrations of various elements on the glass substrates. Based on these results, we speculate that most or all of the adsorbed hydrocarbon material could be removed from a glass substrate through synergistic effects between sodium carbonate, which provides the alkaline condition, and anionic surfactants, which likely interacted with adsorbed cationic materials. This resulted in dramatic alteration in the wettability of bitumen-treated glass surfaces—from oil-wet to water-wet.     

含三嗪环阴离子Gemini表面活性剂的性能研究

研究了含三嗪环阴离子Gemini表面活性剂增溶、流变、溶致液晶、囊泡等性能。结果表明:增溶量随Gemini表面活性水基和联接基长度)对其水溶液的黏度有相同的影响;C6-2-C6、C8-2-C8、C8-3-C8、C8-4-C8、C8-6-C8、C12-2-C12在质量分数剂疏水链长度的增长而增大,C8-n-C8(n=23,4,6,)的增溶量随联接基长度增加而增加,C12-2-C12与SDS的复配体系比SDS的增溶量大,C12-2-C12与CTAB的复配体系比这2种表面活性剂单独使用时的增溶量小;Gemini表面活性剂溶液分子结构(疏分别为42.3%,37.8%,33.5%,30.4%,27.6%2,0.3%时均产生层状的溶致液晶;0.01 mol/L的单一Gemini表面活性剂水溶液均不能形成囊泡,而当n(C12-2-C12)∶n(CATB)为8∶2或9∶1时,复配体系的水溶液形成了大量的囊泡结构。     

全氟壬烯氧基苯磺酸钠/十二烷基硫酸钠复配体系的溶液性能

研究了全氟壬烯氧基苯磺酸钠(OBS)与十二烷基硫酸钠(SDS)复配比对其水溶液表面张力、油水界面张力、铺展性能及发泡性能的影响。结果表明,OBS/SDS复配比对其水溶液性能影响显著,不同复配比产生不同的协同效果。部分复配体系水溶液与OBS单一组分水溶液相比,表面张力虽略有增加,但油水界面张力显著降低,因此,铺展性能显著改善,原来在环己烷上不铺展,复配后变得铺展。当OBS和SDS按摩尔比0.46∶1复配后,配成浓度为6.17 mmol/L的水溶液其铺展性能最佳,可以在环己烷上快速铺展,并且大幅度减少了OBS氟碳表面活性剂的用量,约降低了46%,大大降低了生产成本;当OBS与SDS按摩尔比为0.15∶1复配时体系油水界面性能、发泡性能的协同效果最好。同时,对不同复配比OBS/SDS的水溶液的最佳铺展浓度进行了研究,发现由表面张力确定的临界胶束浓度并非最佳铺展浓度,二者之间有一定偏差,该差异取决于氟碳表面活性剂和碳氢表面活性剂的性质及配比。     

含氟高分子表面活性剂的合成及其乳化性能的研究

以甲基丙烯酸十二氟庚酯(RfAA)、甲基丙烯酸(MAA)或2-丙烯酰胺-2-甲基丙磺酸(AMPS)、甲基丙烯酸聚乙二醇酯(PEGMA)为共聚单体,以亲氟-亲水-空间位阻的方式,合成了两种含氟高分子表面活性剂P(RfAA-PEGMA-MAA)和P(RfAA-PEGMA-AMPS)。考察了它们对RfAA的乳化性能,探讨了单体种类、单体含量、引发剂用量以及链转移剂用量对单体转化率和聚合物乳化性能的影响。结果表明,n(RfAA)∶n(MAA或AMPS)∶n(PEGMA)=5∶3∶2,引发剂用量为单体总质量的4%,链转移剂用量分别为单体总质量的3%、2%时,所合成的两种含氟高分子表面活性剂对RfAA均表现出了良好的乳化性能,它们的最低表面张力分别为56.3、49.1 mN/m,CMC均约为0.002 g/mL。     

两性离子型Gemini表面活性剂的合成进展

综述了两性离子型Gemini表面活性剂的合成进展,并对此类表面活性剂的合成研究做了展望.     

特种表面活性剂和功能性表面活性剂(ⅩⅣ)——手性表面活性剂的研究进展

综述了手性表面活性剂的研究进展,重点介绍了胆汁盐、毛地黄皂苷、皂苷等天然手性表面活性剂和氨基酸型、烷基糖苷型、酒石酸型、季铵盐型、聚合型等合成手性表面活性剂的研究现状,介绍了其在手性分离、不对称催化、手性介孔无机材料合成等方面的应用,并展望了手性表面活性剂的发展前景。     

Synthesis and Characterization of Novel Surfactants 1,2,3-tri(2-oxypropylsulfonate-3-alkylether-propoxy) Propanes

A series of trimeric sulfonate surfactants 1,2,3-tri(2-oxypropylsulfonate-3-alkylether-propoxy) propanes were prepared by the reaction of glycerin triglycidyl ether with long-chain alcohols, followed by sulfonation with 1,3-propane sultone. Glycerin triglycidyl ether was synthesized by the reaction of epichlorohydrin with glycerin. The chemical structures of the prepared compounds were confirmed by FTIR, ¹H NMR and element analysis. Their solution properties were characterized by use of the method of equilibrium and dynamic surface tension, steady-state fluorescence spectroscopy of pyrene and fluorescence quenching. With the increasing length of the carbon chain, the values of their CMC initially decreased. All these trimeric sulfonate surfactants had good water solubility. These compounds were superior in surface active properties to the reference surfactant SDS. The efficiency of adsorption at the water/air interface (pC₂₀) of these surfactants was very high. It is found that the shorter hydrocarbon chain length of the trimeric sulfonate surfactants, the faster the rate of decrease of surface tension, and the bigger the aggregation number of the trimeric sulfonate surfactants.     

Some Sugar Fatty Ester Ethoxylates as Demulsifiers for Petroleum Sludge

Several ethoxylated sugar fatty ester surfactants were prepared by the reaction of glucose with three fatty acids, namely, adipic, stearic and palmitic acids to produce GA, GS and GP esters. These glucose esters were then ethoxylated by four different molecular weight polyethylene glycols, namely, 400, 1,000, 2,000 and 4,000 mol L^?1. The prepared ethoxylated esters (12 compounds) were characterized by IR and ¹H‐NMR spectroscopy. The surface activity of the prepared compounds was thoroughly studied by measuring the surface tension of different solutions of these compounds at three temperatures, namely 298, 308 and 318 K. From the surface tension‐concentration plots of these compounds some surface properties, such as CMC (critical micelle concentration), Γ_max (maximum surface excess concentration) and A_min (area occupied per molecule) were calculated. The surface properties of the prepared surfactants were correlated to their chemical structure. It was found that the CMC decreases when increasing the molecular weight of polyethylene glycols, whereas A_min increases. Furthermore, the demulsification test was carried out and the results of demulsification efficiency were correlated to the chemical composition of the investigated compounds. Some factors that affect the demulsification efficiency were also considered. The oil phase recovered from the treated sludge was characterized and mixed with fresh crude to improve its API.     

Biosurfactants as Alternatives to Chemosynthetic Surfactants in Controlling Bubble Behavior in the Flotation Process

To examine the usage of biosurfactants as potential alternatives to chemosynthetic surfactants in controlling bubble behavior in the flotation process, a high-speed photographic method was employed to measure the motion of single bubbles and the size distribution of bubbles in the presence of biosurfactants in a laboratory scale flotation column. Deionized water, rhamnolipid, tea saponin and t-C8phenolethoxylateEO9 were used for making various surfactant solutions. Bubble trajectory, dimensions, velocity and size distribution were then determined from the recorded frames using the image analysis software. The results show that similar to chemosynthetic surfactants, the addition of biosurfactants has significant effects on bubble motion and size distribution. The addition of a small amount of tea saponin can significantly dampen bubble deformation, slow down terminal velocity, stabilize bubble trajectory, reduce bubble size and increase the specific surface area of bubbles due to the Marangoni effect. In addition, the biosurfactant effect on bubble behavior has been also found to depend on their type and concentration. The effect of tea saponin, fairly close to C8phenolethoxylateEO9, is stronger than rhamnolipid. The findings in the present study suggest that such biosurfactant as tea saponin may be good substitutes of chemosynthetic surfactants to control bubble behavior in flotation operation.     

Mixed Micelles of Trisiloxane Based Silicone and Hydrocarbon Surfactants Systems in Aqueous Media: Dilute Aqueous Solution Phase Diagrams, Surface Tension Isotherms, Dilute Solution Viscosities, Critical Micelle Concentrations and Application of Regular Solution Theory

Mixtures of trisiloxane type nonionic silicone surfactant (SS) with sodium dodecylsulfate, tetradecyltrimethylammonium bromide or tert-octylphenol ethoxylated with 9.5 ethylene oxide groups were studied in water at 30 °C by dilute aqueous solution phase diagrams, surface tension and dilute solution viscosity methods. The cloud points for the silicone surfactant aqueous solutions increased upon addition of hydrocarbon surfactants indicating the formation of hydrophilic complexes in mixture solutions. The scrutiny of the surface tension isotherms plotted as a function of SS concentration revealed that competitive adsorption effects are the characteristic features in these mixtures depending upon the SS concentration. Otherwise the isotherms exhibited two break points and the difference of concentration between the two break points increased with the increase in SS concentration indicating the cooperative nature of interactions. The micellar mole fractions of individual surfactants were determined by Rublingh's regular solution theory; interaction parameters and activity coefficients were evaluated and interpreted in terms of synergistic type interactions in these mixtures. The surface active parameters in mixture solutions were estimated and their analysis shows that the molecular species in the mixture solutions have a preferential tendency for adsorption at the air/water interface than in association form in the bulk solution. The effect of hydrocarbon surfactants on the intrinsic viscosity of SS micelles was monitored and related to the enhanced hydration in mixed micelles.