水溶液中葡萄糖二酸的吸附机理研究

发布时间：2018-05-29 11:06

本文选题：葡萄糖二酸 + 树脂　；参考：《辽宁大学》2016年硕士论文

【摘要】：葡萄糖二酸是一种天然、无毒的化合物,少量产生于哺乳动物及人体的分泌物和一些植物中。葡萄糖二酸及其衍生物在降低胆固醇、糖尿病的治疗等方面发挥作用逐渐受到医学界的重视。葡萄糖二酸对阳离子有较强的螯合性,可以完美的替代洗涤剂中的磷酸盐。葡萄糖二酸在聚合物单体方面显示出巨大的潜能,例如合成超支化聚酯和生物可降解的新型尼龙。所以在2004年葡萄糖二酸及其衍生物被美国能源部确定为“最具有价值的生物炼制产品”。传统生产葡萄糖二酸的方法是HN03氧化法,该方法存在试剂耗费量大,污染环境等缺点已不能满足实际生产需求。生物法生产葡萄糖二酸有降低原料的损耗、提高产品纯度等优势,作为化学替代法来合成葡萄糖二酸受到越来越多的关注。目前生物法合成葡萄糖二酸的工作仍处于实验室研究阶段,同时分离提取的方法上还没研究。因此,如何对生物法制备葡萄糖二酸的分离方法有待进一步研究。本论文分别应用阴离子交换树脂、中性树脂和活性炭对水溶液中葡萄糖二酸的吸附性能进行研究,并对各实验参数进行了优化选择。研究主要结果如下：首先通过静态吸附研究,筛选了合理的树脂分离条件。在298K和pH=2.01、3.90和6.06条件下,对7种国产离子交换树脂静态吸附筛选,筛选出335树脂作为最佳吸附离子交换树脂(Kf=135.6751mg·g~(-1)),实验中最大吸附量可达350mg·g~(-1),吸附等温线在pH=3.90和298 K条件下满足Freundlich模型,该吸附过程属于优惠吸附。同时还研究了Amberlite XAD4、Amberlite XAD1600N中性树脂和活性炭吸附水溶液中的葡萄糖二酸,研究表明在pH=2.01和298 K时Amberlite XAD4树脂吸附效果最好(Kf=94.38 mg·g~(-1)),并且Freundlich方程可较好的描述葡萄糖二酸在Amberlite XAD4树脂上的吸附平衡,该吸附过程属于优惠吸附。阴离子交换树脂的吸附效果要优于中性树脂和活性炭的吸附效果。根据热力学计算得到吸附过程中的吸附自由能变ΔG,结果表明实验选取的10种吸附剂对水溶液中葡萄糖二酸吸附过程的ΔG0,该反应过程可自发进行。在葡萄糖二酸的动力学研究中,分别采用准一级动力学模型和准二级动力学模型考察了7种离子交换树脂对葡萄糖二酸吸附动力学,拟合结果表明准二级动力学模型和实验数据之间有较好的相关性。离子交换树脂对葡萄糖二酸的吸附速率由扩散过程控制。在上样液流速分别为1 mL·min~(-1)和2 mL·min~(-1)条件下,探究了335树脂和711树脂动态吸附柱实验。结果表明pH=3.90,吸附温度为298 K时,335树脂优于711树脂；上样流速1 mL·min~(-1)优于2 mL·min~(-1).
[Abstract]:Gluconic acid is a natural, non-toxic compound produced in small quantities in mammalian and human secretions and in plants. Gluconic acid and its derivatives play an important role in reducing cholesterol and treating diabetes mellitus. Gluconic acid has strong chelating ability to cationic acid and can be used as a perfect substitute for phosphates in detergents. Gluconic acid has great potential in polymer monomers, such as hyperbranched polyester and new biodegradable nylon. So in 2004, Glucopolylic acid and its derivatives were identified as "the most valuable Bio-Refining products" by the US Department of Energy. The traditional method of producing gluconic acid is HN03 oxidation method, which has many disadvantages, such as high reagent consumption and environmental pollution. The production of gluconic acid by biological method has the advantages of reducing the loss of raw materials and improving the purity of the product. As a chemical substitute method, the synthesis of gluconic acid has attracted more and more attention. At present, the biosynthesis of gluconic acid by biological method is still in the laboratory stage, and the method of separation and extraction has not been studied. Therefore, how to separate the preparation of Gluconic acid by biological method needs further study. In this paper, the adsorption properties of gluconic acid in aqueous solution were studied by anion exchange resin, neutral resin and activated carbon, and the experimental parameters were optimized. The main results are as follows: firstly, the reasonable separation conditions of resin were screened by static adsorption. Under the conditions of 298K, pH 2.01 ~ 3.90 and 6.06, the static adsorption of seven kinds of domestic ion-exchange resins was screened, and 335 resin was selected as the best adsorption ion-exchange resin. The maximum adsorption capacity was up to 350mg ~ (-1), and the isotherm of adsorption met the Freundlich model at pH=3.90 and 298K, and the adsorption isotherms were obtained at 298K and 298K, respectively, and the adsorption isotherms met the Freundlich model under the conditions of pH=3.90 and 298K. The adsorption process belongs to preferential adsorption. The adsorption of gluconic acid in aqueous solution by Amberlite XAD4 Amberlite XAD1600N neutral resin and activated carbon was also studied. The results show that the adsorption effect of Amberlite XAD4 resin is the best at pH=2.01 and 298K, and the Freundlich equation can describe the adsorption equilibrium of Glucopolylic acid on Amberlite XAD4 resin, which is a preferential adsorption process. The adsorption effect of anion exchange resin is better than that of neutral resin and activated carbon. According to the thermodynamic calculation, the adsorption free energy change 螖 G was obtained. The results showed that the adsorption process of gluconic acid in aqueous solution by 10 kinds of adsorbents selected in the experiment was 螖 G 0, and the reaction process could be carried out spontaneously. In the kinetic study of gluconic acid, the adsorption kinetics of 7 kinds of ion exchange resins for gluconic acid was investigated by using quasi first order kinetic model and quasi second order kinetic model, respectively. The fitting results show that there is a good correlation between the quasi-secondary kinetic model and the experimental data. The adsorption rate of Glucopolylic acid by ion exchange resin is controlled by diffusion process. At the flow rate of 1 mL / min ~ (-1) and 2 mL / min ~ (-1), the dynamic adsorption column experiments of 335 resin and 711 resin were investigated. The results showed that when pH was 3.90, adsorption temperature was 298K, the resin was superior to 711 resin, and the flow rate of sample was 1 mL / min ~ (-1), which was better than 2 mL / min ~ (-1) 路min ~ (-1).
【学位授予单位】：辽宁大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：TQ28;O647.3

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