低浓度鼠李糖脂的自聚集及对多孔介质中十二烷的增溶

发布时间：2018-03-04 08:10

本文选题：鼠李糖脂　切入点：自聚集　出处：《湖南大学》2016年硕士论文　论文类型：学位论文

【摘要】：随着工农业的发展,各种各样的有机污染物通过人为排放或是意外泄露等途径进入环境中,这些有机物进入土壤和地下水,对人类的生命健康造成长期的威胁。生物表面活性剂作为一种两亲性物质在生物修复处理有机污染的研究中得到了广泛的关注。在生物修复中,表面活性剂的主要作用之一是表面活性剂能够增加疏水性污染物的溶解度,而表面活性的这一特性和其在溶液聚集体的形成状态有关;另一方面,生物表面活性剂较高的成本是阻碍其在实际中广泛应用的主要原因之一。基于此,本文研究了在低浓度条件下生物表面活性剂鼠李糖脂在电解质溶液中的自聚集现象;同时通过一维流场柱实验研究了低浓度鼠李糖脂对饱和多孔介质中剩余饱和度十二烷的增溶的影响。鼠李糖脂二糖脂的自聚集实验在磷酸盐缓冲溶液中进行,在五个pH(6.0,6.5,7.0,7.5,8.0)条件下进行,鼠李糖脂二糖脂在这五个pH条件下的临界胶束浓度(CMC)分别为62、78、82、83、82μM。研究结果表明,鼠李糖脂二糖脂在低浓度下有聚集体形成,聚集体的粒径在10 nm到数十纳米之间。在低浓度条件下,鼠李糖脂浓度和溶液pH对聚集体粒径要较大影响。当溶液pH不高于7.0且鼠李糖脂二糖脂浓度不超过100μM时,聚集体的粒径随着表面活性剂浓度的升高而减小。当鼠李糖脂在10~100μM(接近临界胶束浓度)时,聚集体的粒径随着溶液pH的升高而减小。当鼠李糖脂的浓度高于100μM时,鼠李糖脂浓度和溶液pH的变化对聚集体的粒径均没有明显的变化。动力学光散射(DLS)的研究结果表明聚集体的分布呈单峰分布,而且冷冻透射电镜(cryo-TEM)的检测结果和DLS测得的聚集体尺寸大小相似。鼠李糖脂二糖脂多组分的特性可能是造成鼠李糖脂在低浓度条件下自聚集现象的原因。而且,我们的研究表明基于测定表面张力获得的CMC可能不适合用于判断多组分组成的表面活性剂聚集体形成的条件。鼠李糖脂溶液的淋洗可以作用促进饱和多孔介质中十二烷的增溶,500μM条件下鼠李糖脂的淋洗实验获得了显著的效果,流出液中十二烷的浓度达到了150μM。对流出液中聚集体粒径、zeta电位、和鼠李糖脂穿透曲线的研究表明,鼠李糖脂对多孔介质中十二烷的增溶机制是基于鼠李糖脂聚集体的形成。
[Abstract]:With the development of industry and agriculture, a variety of organic pollutants enter the environment through anthropogenic discharge or accidental leakage. These organic pollutants enter the soil and groundwater. Biosurfactants, as a amphiphilic substance, have received extensive attention in the treatment of organic pollution by bioremediation. One of the main functions of surfactants is that surfactants can increase the solubility of hydrophobic pollutants, and this property of surface activity is related to their state of formation in solution aggregates; on the other hand, The high cost of biosurfactant is one of the main reasons that hinder its wide application in practice. Based on this, the self-aggregation of rhamnolipid in electrolyte solution at low concentration is studied. At the same time, the effect of low concentration rhamnose on the solubilization of residual saturation 12 alkane in saturated porous media was studied by one-dimensional flow field experiment. The self-aggregation experiment of rhamnolipid disulfide was carried out in phosphate buffer solution. The critical micelle concentrations (CMCs) of rhamnolipid disulfide at five pH values of 6.0 ~ 6.5 ~ 7.5 ~ 7.5 ~ 8.0) were 622 / 78 ~ 82 ~ 8382 渭 m respectively. The results showed that rhamnolipid was formed collectively at low concentration, and the critical micelle concentration (CMC) of rhamnolipid disulfide at the five pH values was 622 ~ 78 ~ 82 ~ 8382 渭 m, respectively, and the results showed that rhamnolipid was formed collectively at a low concentration. The particle size of aggregates ranged from 10 nm to dozens of nanometers. At low concentrations, rhamnolipid concentration and solution pH had a great effect on the particle size of aggregates. When the pH of solution was not higher than 7.0 and the concentration of rhamnolipid disulfide was not more than 100 渭 M. The particle size of aggregates decreased with the increase of surfactant concentration. When rhamnolipid concentration was 10 ~ 100 渭 m (close to critical micelle concentration), the particle size of aggregates decreased with the increase of pH value of solution, and when the concentration of rhamnolipid was higher than 100 渭 M, the particle size of aggregates decreased with the increase of pH. The concentration of rhamnolipid and the pH of the solution had no obvious changes on the particle size of the aggregates. The results of kinetic light scattering (DLSs) showed that the distribution of the aggregates showed a single peak distribution. The size of aggregates measured by cryo-TEM was similar to that measured by DLS. The characteristics of rhamnolipid disulfide multicomponent may be the cause of self-aggregation of rhamnolipid at low concentration. Our study shows that the CMC based on the determination of surface tension may not be suitable for judging the formation of multi-component surfactant aggregates. The elution of rhamnolipid solution can promote the formation of saturated porous media. The elution experiment of rhamnolipid under the condition of 12 渭 M solubilization of alkane obtained remarkable effect. The concentration of 12 alkanes in effluents reached 150 渭 M. the study on the particle size of aggregates and the penetration curves of rhamnolipid showed that the solubilization mechanism of rhamnolipid on 12 alkanes in porous media was based on the formation of rhamnolipid aggregates.
【学位授予单位】：湖南大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：X53;X523

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