Synthesis of highly ordered supermicroporous silica using short-chain cationic trimeric surfactant as structure-directing agent

Highly ordered supermicroporous silica was synthesized by short chains cationic trimeric surfactant [C₁₀H₂₁N⁺(CH₃)₂(CH₂)₂N⁺(CH₃)(C₁₀H₂₁) (CH₂)₂N⁺(CH₃)₂C₁₀H₂₁] · 3Br⁻ (denoted C_10-2-10-2-10) with a short spacer group (s = 2) as the structure-directing agent and tetraethyl orthosilicate as the precursor. The obtained samples were characterized by small-angle X-ray diffraction, high resolution transmission electron microscopy, and N₂ adsorption–desorption. The results showed that the pore structure of the resulting samples belonged to the two-dimensional hexagonal structure (space group 2D-p6mm) with a pore size from 1.92 to 2.16 nm, which was within the supermicroporous range. The high-quality supermicroporous silica was formed at a low molar ratio of C_10-2-10-2-10 to tetraethyl orthosilicate (0.08:1), which indicated that the self-assembly ability of C_10-2-10-2-10 was stronger than that of corresponding monovalent surfactants. We strictly compared the methods of calculating surface area and pore size of supermicroporous materials, and the surface area was found to be in the range of 910–1,135 m² g⁻¹ by the α_s plot method. With the increase of hydrothermal temperature, the ordering of the supermicroporous structure increased first then decreased, at the same time the pore size was enlarged.     

Protease stabilization by highly concentrated anionic surfactant mixtures

We have found that anionic surfactants such as linear alkylbenzene sulfonate (LAS) can solubilize proteases in a substantially nonaqueous environment without loss of proteolytic activity. Moreover, in mixtures of anionic and nonionic surfactants with a moderate amount of water (water less than 30 wt%), controlled levels of LAS and water solubilize proteases; yet, in these concentrated surfactant mixtures, enzymes maintain their activity for extended periods. Experimental design techniques have been used to delineate the relationship between protease stability and the water, pH and anionic surfactant levels in these surfactant concentrates. As the sum of water and LAS levels is increased, maximum enzyme stability is observed, after which stability falls off. At low water and LAS levels (sum of both <20%), protease solubility is low, while at high levels of water and LAS (sum of LAS and water >45%), denaturation predominates. Additionally, we have developed a new and simple method to predict protease stability by which a synthetic peptide is used to measure protease activity directly in the surfactant concentrate. From the application of this new technique to our system and to commercial liquid detergent formulations, it is apparent that water facilitates the loss of activity of proteases in surfactant concentrates by increasing the rate of autolysis.     

微电解法预处理高浓度阴离子表面活性剂废水

考察了不同微电解方式对含高浓度阴离子表面活性剂(AS)废水的预处理效果,结果表明,在铁炭填料分别为F3(铁屑,规格3 mm×10 mm)、C3(活性炭,规格D 2 mm×3 mm),进水pH为3.5,停留时间为30 min的相同条件下,当m(F3):m(C3)=2:1时,二元微电解法对废水AS及COD的平均去除率分别为...     

Preparation of highly dispersed niobium oxide on silica by equilibrium adsorption method

Two series of Nb₂O₅/SiO₂ catalysts are prepared by an equilibrium adsorption method (type A) and a conventional evaporation to dryness method (type E). The loading amounts of type A catalysts were low ( ˜ 0.2 wt% as Nb₂O₅) and those of type E catalysts were varied from 0.1 to 10 wt%. UV/VIS diffuse reflectance spectra of the catalyst samples show that micro particles of Nb₂O₅) are present on the catalysts with high-loading and monomeric or oligomeric niobate species are present on the catalysts with low-loading. By analyzing luminescence spectra of the low-loading samples, we conclude that the type A catalyst contains monomeric NbO₄ tetrahedra and the type E catalyst oligomeric NbO₄ tetrahedra. Propene photo-oxidation on type A catalysts yields propene oxide selectively, formed on monomeric NbO₄, whereas the photo-oxidation on the type E catalyst with low-loading yields propanal selectively. Propanal is the product in decomposition of propene oxide on oligomeric NbO₄ tetrahedra.     

Incorporation of Ag nanostructures into channels of nitrided mesoporous silica

Nitrided mesoporous silica was used as a host for accommodating nano-silver into the channels. The nitridation of the mesoporous silica host, i.e. SBA-15, with ammonia caused the generation of –NH_x groups on the surface. The following impregnation of the nitrided SBA-15 with aqueous AgNO₃ solution and further reduction led to formation of silver nanostructures in the channels. The samples were characterized by FTIR, XRD, TEM and XPS techniques. The impregnation time has effect on the morphology of the resulting nanostructures. The interaction between silver species and surface –NH_x was the key to immobilize Ag in the channels. A scheme was proposed to illustrate the synthesis of Ag nanostructures using nitrided mesoporous host.     

Formulating middle-phase microemulsions using mixed anionic and cationic surfactant systems

Although mixtures of anionic and cationic surfactants can show great synergism, their potential to precipitate and form liquid crystals has limited their use. Previous studies have shown that alcohol addition can prevent liquid crystal formation, thereby allowing formation of middle-phase microemulsions with mixed anionic-cationic systems. This research investigates the role of surfactant selection in designing alcohol-free anionic-cationic microemulsions. Microemulsion phase behavior was studied for three anionic-cationic surfactant systems and three oils of widely varying hydrophobicity [trichloroethylene (TCE), hexane, and n-hexadecane]. Consistent with our hypothesis, using a branched surfactant and surfactants with varying tail length allowed us to form alcohol-free middle-phase microemulsion using mixed anionic-cationic systems (i.e., liquid crystals did not form). The anionic to cationic molar ratio required to form middle-phase microemulsions approached 1∶1 for univalent surfactants as oil hydrophobicity increased (i.e., TCE to hexane to n-hexadecane); even for these equimolar systems, liquid crystal formation was avoided. To test the use of these anionic-cationic surfactant mixtures in surfactant-enhanced subsurface remediation, we performed soil column studies: Greater than 95% of the oil was extracted in 2.5 pore volumes using an anionic-rich surfactant system. By contrast, cationic-rich systems performed very poorly (<1% oil removal), reflecting significant losses of the cationic-rich surfactant system in the porous media. The results thus suggest that, when properly designed, anionic-rich mixtures of anionic and cationic surfactants can be efficient for environmental remediation. By corollary, other industrial applications and consumer products should also find these mixtures advantageous.     

电极超滤膜生物反应器处理阴离子表面活性剂废水

化妆品生产过程中产生大量的阴离子表面活性剂废水,具有有机物浓度高和易产生泡沫的特点,影响普通超滤膜生物反应器（UMBR）的处理效果和稳定运行。采用自制的电极超滤膜生物反应器（EMBR）处理阴离子表面活性剂废水,考察电流强度对EMBR污染物处理效果和活性污泥性质的影响,探索膜污染的机理。结果表明：与UMBR相比,在电场能的作用下,EMBR滤饼层的有机物含量较低,跨膜压差（TMP）降低50%左右,膜污染较轻。当电流强度为10 mA时,COD去除率和微生物活性最高,分别为97.92%和41.6 mg/（g TSS·h）;滤饼层有机物含量最低,PN、PS和HA的浓度分别为5.6、8.02、0.85 mg/L。较低的电流强度即可促进微生物活性和污染物去除率的提高,有效控制膜污染。     

化学立业 责任立本——罗地亚高分散白炭黑项目在青岛正式投产

<正>10月20日,由法国罗地亚集团投资的白炭黑项目在青岛高新区胶州湾北部园区举行隆重的开业庆典。青岛市委常委、副市长张惠,罗地亚集团主席兼首席执行官尚-皮耶·克拉马迪奥,以及青岛市相关部门、轮胎等下游企业、行业媒体等100多人出席仪式并参观了工厂。     

电极超滤膜生物反应器处理阴离子表面活性剂废水

化妆品生产过程中产生大量的阴离子表面活性剂废水,具有有机物浓度高和易产生泡沫的特点,影响普通超滤膜生物反应器（UMBR）的处理效果和稳定运行。采用自制的电极超滤膜生物反应器（EMBR）处理阴离子表面活性剂废水,考察电流强度对EMBR污染物处理效果和活性污泥性质的影响,探索膜污染的机理。结果表明：与UMBR相比,在电场能的作用下,EMBR滤饼层的有机物含量较低,跨膜压差（TMP）降低50%左右,膜污染较轻。当电流强度为10 mA时,COD去除率和微生物活性最高,分别为97.92%和41.6 mg/（g TSS·h）;滤饼层有机物含量最低,PN、PS和HA的浓度分别为5.6、8.02、0.85 mg/L。较低的电流强度即可促进微生物活性和污染物去除率的提高,有效控制膜污染。     

Contact angle of surfactant solutions on precipitated surfactant surfaces. III. Effects of subsaturated anionic and nonionic surfactants and NaCl

The contact angles of saturated calcium dodecanoate (CaC₁₂) solutions containing a second subsaturated surfactant on a precipitated CaC₁₂ surface were measured by using the drop shape analysis technique. The subsaturated surfactants used were anionic sodium dodecylsulfate (NaDS), anionic sodium octanoate (NaC₈), and nonionic nonylphenol polyethoxylate (NPE). Comparing at the critical micelle concentration (CMC) for each surfactant, NaC₈ was the best wetting agent, followed by NaDS, with NPE as the poorest wetter (contact angles of 32⁰, 42⁰, and 62⁰, respectively). Surface tension at the CMC increased in the order NaC₈<NPE<NaDS, and subsaturated surfactant adsorption increased in the order NPE≪NaDS (1.4 vs. 84 μmole/g); adsorption of the NaC₈ was not measurable. Interfacial tension (IFT) reduction at the solid-liquid interface due to subsaturated surfactant adsorption is an important contribution to contact angle reduction, in addition to surface tension reduction at the air-water interface. Surfactant adsorption onto the soap scum solid is crucial to solid-liquid IFT reduction and to good wetting. The fatty acid was the best wetting agent of the three surfactants studied, probably because calcium bridging with the carboxylate group synergizes surfactant adsorption onto the solid of the higher molecular weight soap. NaCl added to NaDS surfactant results in depressed CMC, lower surface tension at the CMC, decreased NaDS adsorption onto the solid, and decreased reduction in solid-liquid IFT. The contact angle is not dependent on the NaCl concentration for NaDS. The NaCl causes an increased tendency to form monolayers, which decrease air-water surface tension, but a decreased tendency to form adsorbed aggregates on the solid; the two trends offset each other, so wettability is not affected by added salt. The Zisman equation does not describe the wetting data for these systems well except for NaDS, further emphasizing the danger of ignoring solid-liquid IFT reduction in interpreting wetting data in these systems.     

一种新型阴离子型表面话性剂的合成研究

以2-十二酮、丙三醇和丙磺酸内酯为原料,通过两步法合成出一种新型的缩醛型可降解表面活性剂--3-[(2-癸基-2-甲基-1,3-二氧杂环戊烷-4)-甲氧基]丙烷-1-磺酸钠盐.产物结构经红外光谱和核磁共振氢谱分析表征,数据结果显示产品为目标产物.通过利用电化学方法测定产物的电导率,分析产物水溶液物理性质与浓度关系,测定表面活性剂的临界胶束浓度接近8.0×10-3mol/L.     

Effect of nonionic surfactant upon surface tension of anionic surfactant

The surface tension of sodium dodecyl sulfate was determined in the presence of nonionic surfactant. The nonionic surfactant used was homogeneous pentaethyleneglycol-n-dodecylether which has no poisson distribution of added mole numbers of ethyleneoxide. The concentration of sodium dodecyl sulfate was changed at various fixed concentrations of homogeneous pentaethyleneglycol-n-dodecylether. Two inflection points were observed on each surface tension curve, and the surface tension maintained a constant value between the inflections, regardless of the concentrations of added homogeneous pentaethyleneglycol-n-dodecylether. However, the concentrations of sodium dodecyl sulfate at the inflections were affected at the concentrations of homogeneous pentaethyleneglycol-n-dodecylether, respectively. When the homogeneous pentaethyleneglycol-n-dodecylether concentrations were fixed below the critical micelle concentration, the concentration of sodium dodecyl sulfate at the lower inflection point decreased with increasing concentration of homogeneous pentaethyleneglycol-n-dodecylether, while that of the higher was hardly influenced. If the homogeneous pentaethyleneglycol-n-dodecylether concentrations were fixed above the critical micelle concentration, the sodium dodecyl sulfate concentrations at the two inflections both increased with an increment of homogeneous pentaethyleneglycol-n-dodecylether concentration. These results were interpreted in terms of mixed surface layer and mixed micelles consisting of sodium dodecyl sulfate and homogeneous pentaethyleneglycol-n-dodecylether. Also, the surface tension curves of homogeneous pentaethyleneglycol-n-dodecylether in the presence of sodium dodecyl sulfate, as well as those of sodium dodecyl sulfate with given concentrations of homogeneous pentaethyleneglycol-n-dodecylether, were studied.     

Studies on precipitation of highly dispersed silica from sodium metasilicate–sodium hydrogencarbonate system

A novel procedure is presented for precipitation of highly dispersed silica from sodium metasilicate solution using sodium hydrogencarbonate. In the course of silica precipitation, hydrophobicity‐inducing agents were introduced to the reactor, including derivatives of saturated and unsaturated higher fatty alcohols and nonylphenylpolyoxyethyleneglycol ethers. Silicas of variable physicochemical characteristics were obtained. Analysis of the principal physicochemical properties of the silicas was performed, their surface morphology was examined using scanning electron microscopy while particle size distribution, polydispersity and tendency to form the agglomerate structures were estimated by the dynamic light scattering technique. The zeta potential was also measured by estimation of electrophoretic mobility. Sodium hydrogencarbonate solution was found to be a very good silica‐precipitating agent in solutions of sodium metasilicate. The hydrated silica obtained demonstrated low bulk density and a high capacity to absorb paraffin oil. © 2002 Society of Chemical Industry     

Enzymatic synthesis of soluble phenol polymer in water using anionic surfactant as additive

In phosphate–citric acid buffer (pH = 8.0) containing sodium dodecylbenzenesulfonate (SDBS) as a surfactant, enzymatic polymerization of phenol catalyzed by horseradish peroxidase (HRP) is efficiently performed. The as‐synthesized phenol polymer is completely soluble in organic solvents such as dimethylfomamide, dimethylsulfoxide, acetone and tetrahydrofuran. The aqueous micelle system provides a new environmentally friendly method for HRP‐catalyzed phenol polymerization. The effects of the dosage of SDBS and reaction temperature on the yield of the target phenol polymer are investigated. The soluble phenol polymer is composed of phenylene and oxyphenylene units as determined using infrared and ¹ H NMR spectral analyses. The number‐average molecular weight calculated from gel permeation chromatography (GPC) is in the range 900–1500 g mol^?1 and the dispersity in the range 3.4–6.3. In all cases, the values of weight‐average molecular weight characterized using GPC–static light scattering are tens of thousands. It is concluded that a branched structure is produced in the aqueous micelle system. The phenol polymer prepared possesses good thermal stability for it is completely decomposed at a temperature as high as 628 °C in air.     

流动注射分析仪测定地表水中阴离子表面活性剂的研究

采用Quiekchem8500s2型连续流动注射分析仪对地表水中阴离子表面活性剂进行测定,标准曲线的相关系数为0．9995,方法检出限为0．004mg／L。对2种浓度的标准样品进行分析,测得值均在其保证值范围内。该方法简单、快速,对实际地表水样的测定结果与标准方法的相对误差在4．07％～10．64％,这表明流动注射法适用于地表水样品的快速测定。     

氟碳阴离子表面活性剂的合成与性能

以十六氟壬醇、顺酐和亚硫酸钠为原料合成了氟碳烷基琥珀酸酯磺酸盐。根据正交实验结果,确定了最佳合成工艺条件,酯化反应:十六氟壬醇与马来酸酐的摩尔比为1∶1.2,反应时间为4 h,反应温度为85℃,催化剂用量为十六氟壬醇的6%,产品的转化率为98.02%;磺化反应:马来酸单酯与无水亚硫酸钠的配比为1∶1.2,反应时间为1.5 h,反应温度为75℃,产品的转化率为98.51%。对产物的性能进行测定,其临界胶束浓度是9.47×10-4mol/L,表面张力是31.13 mN/m。     

Switchable surfaces from highly hydrophobic to highly hydrophilic using covalent imine bonds

The formation of materials with switchable wettability is extremely important for various applications such as in separation membranes or liquid transportation. Here, we report for the first time the use of imine bonds in order to prepare switchable hydrophobic/hydrophilic surfaces. Based on a poly(3,4‐ethylenedioxythiophene) surface bearing amino groups, imination reaction allows for reversible functionalization of surfaces with various carbonyl groups. Here, surfaces functionalization induces high hydrophobic properties while the surface structures are preserved. This reaction can be a choice method to prepare switchable surfaces for a large range of applications. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43130.     

Preparation of highly dispersed PEM fuel cell catalysts using electroless deposition methods

A methodology for the electroless deposition (ED) of PtCl₆²⁻ using dimethylamine borane (DMAB) on a Rh-seeded carbon support has been developed for electrochemical and fuel cell applications. This procedure required seeding the carbon with a Rh-precursor catalyst via wet impregnation prior to the exposure of an aqueous ED bath containing PtCl₆²⁻, DMAB, and sodium citrate (complexing/stabilizing agent). Kinetic parameters that affect the extent and rate of PtCl₆²⁻ deposition include concentrations of PtCl₆²⁻, DMAB, and sodium citrate as well as pH and concentrations of Rh seed sites. A linear relationship between rate and extent of PtCl₆²⁻ deposition and DMAB and Rh concentrations was found while the citrate concentration had little effect on rate and a modest effect on extent. Lastly, extent of PtCl₆²⁻ deposition showed a maximum with respect to pH. Characterization of the Rh-seeded, carbon support by transmission electron microscopy (TEM) shows that the Rh particle diameters remain constant at 33–43 Å as the Rh weight loading increases from 0.4% to 2.2% to 4.4%. Further, after deposition of similar loadings of Pt, TEM analysis shows Pt particle diameters decrease with increasing Rh loading, since equal amounts of Pt were deposited on greater numbers of Rh seed particles. This pattern suggests a shell-core geometry, where Pt is deposited more or less uniformly around a Rh core.