表面活性剂和胶原间的相互作用

研究了十二烷基硫酸钠（SDS），二十烷基苯磺酸钠（SDBS），溴化十六烷基吡啶翁（CPB）和Igepal CA-720等表面活性剂与胶原（来源于牛跟腱）间的相互作用，发现了不同的反应条件下，上述离子性表面活性剂的吸附等温线，得到了适当条件下的吸附等温线，同时发现在等电条件下等温线呈对数关系，Igepal没有吸附，表面活性剂与胶原的作瓿 其质量的变化是相互关联的，这种变化取决于反应条件，即pH值和反应溶液中的离子强度，胶原的膨胀程度（am)被用来描述这种变化，在pH3.0，无SDBS存在且在低的离子强度下，胶原得到了大的膨胀；加入SDBS将会导致强烈的消肿作用，并且当胶原对SDBS的结合量达到1mmol/g时，am的值将不再随SDBS结合量的进一步增加而变化，在高的离子强度下，am与SDBS的平衡吸附量无关，在等电条件下am的变化明显小于在酸性条件下的变化，两种条件下am具有相反的特点。     

制革中一些物理化学问题讨论

本文讨论了皮革制造中的三个理论问题，一是表面电荷与等电点（ＰＩ）之间差别，二是三价铬鞣液配制中公式的简单来源，三是生皮在碱液中膨胀的机理。     

酸性大红3R与β-环糊精包合体系的光谱研究及应用

采用荧光光谱与紫外-可见光谱研究β-环糊精与工业染料酸性大红3R形成的包合体系.在包合体系最大吸收波长506nm、最佳pH值5.0和最佳包合时间40min条件下,根据Benesi-Hildebrand方程,测定计算出β-环糊精与酸性大红3R的包合比是2:1,包合常数是1.22×106 L2/mol2.考察了不同类型表面活性剂[十二烷基硫酸钠(SDS)、十二烷基苯磺酸钠(SDBS)、十六烷基三甲基溴化铵(CTAB)及平平加O]对包合体系光谱的影响,阴离子表面活性剂与非离子表面活性剂对包合体系的光谱无影响,而阳离子表面活性剂会改变其光谱特征.同时将SDS、SDBS和平平加O分别应用于酸性大红3R-β-环糊精染色体系中上染柞蚕丝,不匀率均下降.     

无盐浸酸及助剂的研究

本文从裸皮在酸性条件下的膨胀原理出发，研制浸酸助剂，使裸皮在酸性条件下不膨胀而达到无盐浸酸的目的。试验研究发现，浸酸助剂可包括两个组分：一是用于封闭氨基、抑制酸膨胀：另一组分是助渗剂，以保证前者渗透均匀、深入，避免在表面收敛过强。根据试验确定了两组分的比例，结果表明，使用２５％～２７％的浸酸助剂（以碱皮重计），不仅可以免去食盐的使用，而且可以较好的分散纤维，同时增加铬的吸收，减少中性盐及铬的排放。使用浸酸助剂不改变常规工艺，制造的蓝湿革皮也不改变铬鞣革的特征。     

基于吸附原理的皮革等电点测定新方法

试验表明,十二烷基苯磺酸钠(SDBS)在皮革上的吸附主要为静电吸附。根据这一原理,以皮革样品为吸附剂,以十二烷基苯磺酸钠(SDBS)为吸附质,建立了一种测定皮革等电点的新方法—SDBS吸附法。该方法的优化试验条件是:用0.2g皮革样品对100mL浓度为0.5mg/mL的SDBS溶液进行吸附(30℃,4h),获得平衡吸附量qe-pH曲线,进而得到皮革样品的等电点值。用该方法测得的皮革的等电点分别为:生皮8.4～8.5,脱灰皮7.1～7.2,浸酸皮5.8～5.9,铬鞣革7.7～7.9,铝鞣革8.5～8.6,锆鞣革7.3～7.4,戊二醛鞣革5.1～5.2,TWT鞣革5.8～5.9。这些等电点数据基本符合实际情况,表明该方法具有良好的普遍适用性。     

表面活性剂对制革浸酸工序的影响

将十二烷基硫酸酯钠（阴离子型表面活性剂）、十二烷基三甲基氯化铵（阳离子型表面活性剂）和平平加O（非离子型表面活性剂）分别以不同用量添加到浸酸液中,观察浸酸工序完成所需要的时间,测定浸酸废液蛋白质含量和悬浮物含量,并对浸酸皮组织切片进行显微镜观察。将浸酸皮进行铬鞣,对铬鞣革进行感官评价,并测定铬鞣革收缩温度和抗张强度。研究结果表明：在浸酸液中添加阴离子型、阳离子型和非离子型表面活性剂,均能加快浸酸速度;当浸酸液中表面活性剂浓度略大于其临界胶束浓度时,表面活性剂就能明显加速浸酸过程;三类表面活性剂使浸酸皮胶原纤维分散的程度依次为：阴离子型表面活性剂〉非离子型表面活性剂〉阳离子型表面活性剂;将表面活性剂应用于浸酸工序后,所得蓝革柔软度、粒面平细度以及粒纹清晰程度均优于空白样,并且表面活性剂处理样抗张强度均高于空白样。     

制革固体废弃物对皮革染料的吸附等温线和动力学研究

表明了工业植鞣革和铬鞣革固体废物具有较强的吸附能力,可以经济有效的地去除制革废水中的染料。废水取自皮革湿整理工序,分析了两种皮革废物(铬鞣革和植鞣革)吸附过程的pH值以及染料废水的浓度变化范围。在最佳的吸附pH(2~3)下,得到铬鞣革屑对酸性黄194染料、酸性红357染料和酸性黑210染料的吸附等温线和吸附动力学。酸性黄194染料、酸性红357染料和酸性黑210染料的吸附等温线为C1、H2和H3形,分别符合Henry、Langmuir和BET吸附模型。三种染料的动力学均符合Elovich模型,表明吸附过程为化学吸附。对酸性黄194染料的吸附分别用拟一级动力学和拟二级动力学方程进行拟合,酸性红357染料用拟二级动力学方程进行拟合。此外,酸性黄194染料的吸附受边界层扩散的影响,而酸性红357染料和酸性黑210染料的吸附受到颗粒内扩散的影响。     

纳米TiO2在水分散体系中的稳定性

研究pH值、不同离子性的表面活性剂和高分子分散剂聚乙烯吡咯烷酮对纳米二氧化钛水分散体系稳定性的影响。研究表明，体系pH值9时，溶胶最稳定；在等电点（pH值3．5）时，纳米微粒很快发生聚沉。阴离子表面活性剂达到一定浓度时，可提高溶胶的稳定性；阳离子表面活性剂在中性和碱性条件下，会破坏溶胶的稳定性，而当其偏酸性（pH值为5，但大于3．5）时，能提高胶体的稳定性；加入聚乙烯吡咯烷酮，可提高溶胶的稳定性。     

阴离子和非离子表面活性剂在皮质上结合时的相互影响

非离子表面活性剂只有在事先或同时使用阴离子表面活性剂时才能被未鞣皮粉吸附.阴离子表面活性剂的疏水基为非离子表面活性剂提供了一个疏水结合点,阴离子表面活性剂和非离子表面活性剂通过电荷的相互作用与皮粉结合.人们可以从温度升高、结合增加;醇量增加、结合减少来认识疏水基的性质.铬革与阴离子表面活性剂结合缓慢,但在量和对pH的关系上和生皮很相似.然而,随着硫酸钠添加量的增加,阴离子表面活性剂与生皮结合增加,但与铬革结合减少.非离子表面活性剂在铬皮粉上的吸附减少,因为在铬革中形成流水的相互作用受到强烈干扰.     

高吸收铬鞣新方法（I）：酶在鞣制中的作用

针对工业污染物排放日益严格的环保法规,促使研究人员对鞣制工艺进行革新,开发环境友好的技术,以达到低污染和高吸收的目的。然而,有关采用生物技术来减少铬污染、成本低廉、工业生产上可行的高吸收铬鞣工艺还未见报道。本文采用了一种酸性蛋白酶辅助铬鞣工艺,研究了不同的酶处理条件对铬鞣剂吸收率的影响,得到了最佳的工艺条件。选择三种不同的有浴和无浴鞣制工艺进行比较,试验工艺中碱式硫酸铬（BCS）的用量分别为6％和8％。结果表明,在pH4．5条件下进行的酶助铬鞣工艺,其铬的渗透和分布情况都比其它鞣制工艺要好得多,尽管鞣制进行的pH较高,但试验鞣革的粒面上并没有发现铬的沉积,扫描电子显微镜分析也证实了这一点。在最佳酶辅助铬鞣工艺条件下,铬的吸收率超过了95％,其鞣革中的铬含量要比传统的铬鞣革高一些。物理和感官评价结果表明,酶辅助铬鞣革的性能与传统的铬鞣革是一样的。     

Interaction of mixture of anionic surfactants with collagen

Study focused on interaction of collagen fibres of collagen I with anionic surfactants sodium dodecylbenzene sulphonate (SDBS), sodium dodecyl sulphate (SDS) and their mixtures at pH = 6, at two ionic strengths (I = 0.06 mol L(-1) and I = 0.4 mol L(-1)) and laboratory temperature. Surfactants and their mixtures were characterised by their critical micelle concentration (c.m.c.), composition of mixed micelles and interaction factor beta according to Rubingh. Dependency of c.m.c. on mixture composition has an opposite tendency at both ionic strengths, which proves the greater influence of added electrolyte on behaviour of SDS than of SDBS. Interaction was evaluated by means of binding isotherms and mass swelling degree alpha(m). The bound quantity partly depends on mixture composition, partly on ionic strength. SDS and mixtures containing its greater quantities are bound more than SDBS (approx. 150% related to SDBS). Increased ionic strength of the environment increases bound quantity in approximately same manner, heedless of adsorbate composition. Even composition of the mixture after interaction with fibres does not markedly alter from initial composition. Fibre swelling is affected by composition of swelling mixture similarly to binding - it increases with growing quantity of surfactants. Greater ionic strength acts against collagen swelling, and at given ionic strength (I = 0.4 mol L(-1)) swelling attains half values compare to swelling at low ionic strength (I = 0.06 mol L(-1)). There are characteristic concentrations of both surfactants and their mixtures (c(s) approximately 0.5 - 1.0 mmol L(-1)) that do not produce swelling. It is assumed that this range of concentrations corresponds to amount of surfactants bound to collagen through electrostatic forces and thus to temporary increase in fibre hydrophobity.     

离子表面活性剂和胶原间的相互作用(续)

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Clay minerals affect the stability of surfactant-facilitated carbon nanotube suspensions

Carbon nanotubes (CNTs), because of their wide application, will inevitably enter aquatic systems, but the fate and transport of their suspensions in the environment are largely unknown. Clay minerals are expected to interact with CNT suspensions, affecting their fate and bioavailability. This study investigated the influence of clay minerals (kaolinite and montmorillonite) on the stability of surfactant (SDBS, CTAB, and TX100) facilitated multiwalled CNT (MWCNT) suspensions. Adsorption of the surfactants by MWCNTs and clay minerals was also examined. This is a first study on the interaction between clay minerals and surfactant-CNT suspensions. Sorption of SDBS by clay minerals and MWCNTs followed the order MWCNTs > montmorillonite approximately kaolinite; but sorption of CTAB and TX100 followed the order montmorillonite > MWCNTs > kaolinite. For SDBS suspended MWCNTs, introduction of montmorillonite and kaolinite could not change their stability; for CTAB suspended MWCNTs, both montmorillonite and kaolinite greatly deposited the suspended MWCNTs; for TX100 suspended MWCNTs, montmorillonite could partially deposit the suspended MWCNTs, whereas kaolinite showed minimal effect. Two mechanisms of clay minerals affecting MWCNT suspensions are (1) removal of surfactants by clay minerals from solution and MWCNT surface and (2) bridging between clay mineral and MWCNTs by surfactant.     

Enhanced soil washing of phenanthrene by mixed solutions of TX100 and SDBS

Increased desorption of hydrophobic organic compounds (HOCs) from soils and sediments is a key to the remediation of contaminated soils and groundwater. In this study, phenanthrene desorption from a contaminated soil by mixed solutions of a nonionic surfactant(octylphenol polyethoxylate, TX100) and an anionic surfactant (sodium dodecylbenzenesulfonate, SDBS) was investigated. Phenanthrene desorption depended on not only aqueous surfactant concentrations and phenanthrene solubility enhancement but also the soil-sorbed surfactant amount and the corresponding sorption capacity of sorbed surfactants. The added surfactant critical desorption concentrations (CDCs) for phenanthrene from soil depended on both sorbed concentrations of surfactants and their critical micelle concentrations (CMCs). Phenanthrene desorption by mixed solutions was more efficient than individual surfactants due to the low sorption loss of mixed surfactants to soil. Among the tested surfactant systems, mixed TX100 and SDBS with a 1:9 mass ratio exhibited the highest phenanthrene desorption. Mixed micelle formation, showing negative deviation of CMCs from the ones predicted by the ideal mixing theory, was primarily responsible for the significant reduction of soil-sorbed amounts of TX100 and SDBS in their mixed systems. Therefore, mixed anionic-nonionic surfactants had great potential in the area of enhanced soil and groundwater remediation.     

Polyethylenimine-modified fungal biomass as a high-capacity biosorbent for Cr(VI) anions: sorption capacity and uptake mechanisms

Heavy metal pollution in the aqueous environment is a problem of global concern. Biosorption has been considered as a promising technology for the removal of low levels of toxic metals from industrial effluents and natural waters. A modified fungal biomass of Penicillium chrysogenum with positive surface charges was prepared by grafting polyethylenimine (PEI) onto the biomass surface in a two-step reaction. The presence of PEI on the biomass surface was verified by FTIR and X-ray photoelectron spectroscopy (XPS) analyses. Due to the high density of amine groups in the long chains of PEI molecules on the surface, the modified biomass was found to possess positive zeta potential at pH below 10.4 as well as high sorption capacity for anionic Cr(VI). Using the Langmuir adsorption isotherm, the maximum sorption capacity for Cr(VI) at a pH range of 4.3-5.5 was 5.37 mmol/g of biomass dry weight, the highest sorption capacity for Cr(VI) compared to other sorbents reported in the literature. Scanning electronic microscopy (SEM) provided evidence of chromium aggregates formed on the biomass surface. XPS results verified the presence of Cr(III) on the biomass surface in the pH range 2.5-10.5, suggesting that some Cr(VI) anions were reduced to Cr(III) during the sorption. The sorption kinetics indicated that redox reaction occurred on the biomass surface, and whether the converted Cr(III) ions were released to solution or adsorbed on the biomass depended on the solution pH. Sorption mechanisms including electrostatic interaction, chelation, and precipitation were found to be involved in the complex sorption of chromium on the PEI-modified biomass.     

pH-induced alterations in stratum corneum properties

Skin-cleansing compositions based on alkyl carboxylates (soaps) have a higher irritation potential than those based on syndet surfactants such as alkyl isethionates or alkyl ether sulphates. Contributing factors include inherent differences in the irritation potential of soaps and syndet surfactants, pH-induced changes in surfactant solution chemistry, and the direct effects of pH on the physical properties of the stratum corneum (SC). Past work has not directly addressed the effect of solution pH on the SC itself and its potential role in cleanser-induced skin irritation. In the current work, alterations to SC properties induced by buffered pH solutions and two strongly ionizable surfactants, sodium dodecyl sulphate and sodium lauryl ether sulphate, at different pH values are measured. By utilizing optical coherence tomography (OCT) and infrared (IR) spectroscopy we have directly measured physical changes in SC proteins and lipids. Our results indicate that SC swelling, which reflects alterations to SC structural proteins, is increased significantly at pH 10, compared to pH 4 and 6.5. The transition temperature (T(m)) of SC lipids is found to increase at pH 10, compared to pH 4 and 6.5, suggesting a more rigid SC lipid matrix. Surfactants cause a further increase in swelling and lipid rigidity. Some aspects of what these results mean for SC physical properties as well as their implications to potential mechanisms of surfactant-induced skin irritation are discussed.     

Modeling tetracycline antibiotic sorption to clays

Sorption interactions of three high-use tetracycline antibiotics (oxytetracycline, chlortetracycline, tetracycline) with montmorillonite and kaolinite clays were investigated undervaried pH and ionic strength conditions. Sorption edges were best described with a model that included cation exchange plus surface complexation of zwitterion forms of these compounds. Zwitterion sorption was accompanied by proton uptake, was more favorable on acidic clay, and was relatively insensitive to ionic strength effects. Calcium salts promoted oxytetracycline sorption at alkaline pHs likely by a surface-bridging mechanism. Substituent effects among the compounds in the tetracycline class had only minor effects on sorption edges and isotherms under the same solution pH and ionic strength conditions. At low ionic strength, greater sorption to montmorillonite than kaolinite was observed at all pHs tested, even after normalizing for cation exchange capacity. These results indicate that soil and sediment sorption models for tetracyclines, and other pharmaceuticals with similar chemistry, must account for solution speciation and the presence of other competitor ions in soil or sediment pore waters.     

Analysis and sorption of psychoactive drugs onto sediment

An analytical method was developed to analyze eight psychoactive pharmaceuticals--including the antiepileptic carbamazepine, the opiates morphine, codeine, dihydrocodeine, the opiode tramadol, and the tranquilizers diazepam, oxazepam, temazepam--and the antibiotic sulfamethoxazole as well as three metabolites (10,11-dihydrocarbamazepine (DHC), 10,11-dihydroxy-10, 11-dihydrocarbamazepine, and N4-acetylsulfamethoxazole) in river sediments. Relative recoveries of all analytes exceeded 97% using either deuterated or 13C15N-labeled surrogate standards. Sorption isotherms of all analytes were constructed at pH 6.5-6.6 on two natural river sediments (Burgen and Dausenau) that differed in organic carbon contents and particle size distributions. Affinities of all analytes were up to an order of magnitude higher for the Dausenau sediment in comparison to the Burgen sediment. Isotherms were well described by the Freundlich model. Sorption of all analytes was linear on the Burgen sediment except for structurally similar carbamazepine (n = 0.90) and DHC (n = 0.88). Conversely, most analytes showed pronounced nonlinear sorption to the Dausenau sediment (n = 0.77-0.92) except for positively charged codeine, dihydrocodeine, and tramadol. Linear sorption of the latter was taken to arise from concentration-independent electrostatic interactions of the organocations with negatively charged surfaces on clay minerals or in the sediment organic matter. Desorption gave rise to hysteresis in 13 out of 16 investigated analyte-sorbent systems. Hysteresis was likely due to slow desorption kinetics beyond 24 h used in the experiment.     

Cr(VI) removal from aqueous solution by activated carbon coated with quaternized poly(4-vinylpyridine)

A composite sorbent (GAC-QPVP) was prepared by coating poly(4-vinylpyridine) onto a granular activated carbon, followed by cross-linking and quaternization processes. The sorbent was characterized by scanning electron microscopy, point of zero charge measurement, and BET analysis. Batch experiments with variable pH, ionic strength, and concentrations of Cr(VI), sorbent, and competing anions were conducted to evaluate the selective sorption of Cr(VI) from aqueous solutions. The results showed that Cr(VI) sorption rates could be described by a reversible second-order kinetics, and equilibrium uptake of Cr(VI) increased with decreasing pH, decreasing ionic strength, and increasing sorbent concentration. The estimated maximum equilibrium uptake of chromium was 53.7 mg/g at pH = 2.25, 30.7 mg/g at pH = 3.65, and 18.9 mg/g at pH = 6.03, much higher than the maximum capacity of PVP-coated silica gel, an adsorbent for Cr examined previously. When compared with the untreated granular activated carbon, sorption onto GAC-QPVP resulted in much less Cr(VI) reduction and subsequent release of Cr(III). The effect of phosphate, sulfate, and nitrate was minor on the selective sorption of Cr(VI). An ion exchange model that was linked with aqueous speciation chemistry described Cr(VI) sorption reasonably well as a function of pH, ionic strength, and Cr(VI) concentration. Model simulations suggested that sorbed Cr(VI) was partially reduced to Cr(III) on the sorbent when pH was less than 4. The presence of Cr(III) on the sorbent was confirmed by the X-ray photoelectron spectroscopic analysis. Overall, the study has demonstrated that GAC-QPVP can effectively remove Cr(VI) from aqueous solutions under a wide range of experimental conditions, without significant Cr(III) release associated with the virgin GAC treatment.