【作者】 于宏斌；

【导师】 董慧茹；

【作者基本信息】 北京化工大学 ， 化学， 2011， 硕士

【摘要】 本文将溶剂浮选技术与络合萃取技术有机结合起来,建立了气浮络合萃取法(Floatation Complexation Extraction,简称FCE)。所建方法具有分离效率高、选择性好、有机溶剂用量少、反萃及溶剂再生简单等优势,对极性有机物稀溶液的分离富集、回收和利用有良好的发展潜力与应用前景。本文将气浮络合萃取法,分别应用于含两性官能团的L-色氨酸和对氨基苯甲酸的分离富集,取得了满意结果,并对其分离机制进行了初步探讨。具体的研究工作及实验结果,如下所述。一、采用气浮络合萃取法对模型化合物L-色氨酸进行了分离富集。在气浮络合萃取过程中,考察了溶液pH、萃取溶剂、电解质NaCl浓度、有机相中P2O4(二(2-乙基己基)磷酸)含量、通气流速和通气时间等因素对L-色氨酸分离富集效果的影响。在所选最佳条件下,对L-色氨酸进行分离富集,对分离富集产物进行反萃取；采用电镜和红外光谱法对所得最终产物进行表征,并通过HPLC分析得到其纯度为99.26%。此外,还对气浮络合萃取L-色氨酸的动力学进行了研究,发现该过程符合2.5级动力学；并对气浮络合萃取法与传统络合萃取法分离富集L-色氨酸的效果进行了比较。二、采用气浮络合萃取法,对实际水样中的对氨基苯甲酸进行分离富集,结果满意。考察了溶液pH、萃取溶剂、电解质NaCl浓度、有机相中P2O4含量、通气流速和通气时间等因素对对氨基苯甲酸气浮络合萃取效果的影响,将所选最佳条件用于实际水样中对氨基苯甲酸的分离富集,并对分离产物进行反萃取,通过红外光谱分析确认了最终产物的结构,通过HPLC分析得到了最终产物的纯度。此外,还将气浮络合萃取法与传统的络合萃取法分离富集对氨基苯甲酸的效果进行了比较。三、对气浮络合萃取分离富集两性官能团化合物的机制进行了初探,认为气浮络合萃取中主要存在两个过程,即气泡传质和络合转移,其中速控步骤为络合反应。气泡传质的引入,其实质是强化了络合萃取过程。由实验结果可知,气浮络合萃取法的效果要明显优于传统的络合萃取,本文还对两者的本质区别进行了分析与探讨。更多还原

【Abstract】 According to the advantage of solvent sublation and complexation extraction, the Flotation Complexation Extraction (FCE) was proposed. Since it has many advantages, such as excellent concentration efficiency, excellent selectivity, lower wastage of organic solvent, simply operation of back-extraction and the solvent reclamation, it has demonstrates a good prospect in the polar organic solutes of its separation and concentration, recover and application.In this paper, FCE was successfully applied to separate and concentrate L-tryptophane and Para-Aminobenzoic Acid (PABA), which belong to organics with amphoteric functional groups, and satisfactory results were obtained. Moreover, their separation mechanisms were studied. Specific studies are described below.In the first part, FCE was applied to separate and concentrate the model compound L-tryptophane from aqueous phase. The effect of pH, extraction solvent, electrolyte (NaCl), concentration of Di(2-ethylhexyl) phosphoric Acid (P204) in organic phase, air flow rate and flotation time were investigated in detail, and the optimal conditions for FCE were obtained. Under the optimal conditions, the L-tryptophane was separated and concentrated from aqueous phase. After the back-extraction, the product was characterized by SEM and FTIR. The purity of the product was determined by HPLC, and the L-tryptophane content was 99.26%. The kinetics of the separation process in L-tryptophane by FCE was also investigated. The experimental results showed that the FCE process of L-tryptophane obeys 2.5 order kinetic equations. Moreover, the comparison of FCE and complexation extraction was discussed in this part.In the second part, FCE was successfully applied to separate and concentrate the model compound Para-Aminobenzoic Acid (PABA) from actual water, and satisfactory results were obtained. The effect of pH, extraction solvent, electrolyte (NaCl), concentration of P204 in organic phase, air flow rate and flotation time were investigated in detail, and the optimal conditions for FCE were gained. Under the optimal conditions, the PABA was separated and concentrated from aqueous phase. After the back-extraction, the product was characterized by FTIR, and it was shown to be PABA. The purity of the product was determined by HPLC. The comparison of FCE and complexation extraction was also discussed.In the third part, the separation mechanism of the separation and concentration of organics with amphoteric functional groups by FCE was studied. There are two processes in the FCE, bubble masstransfer and complexation transfer. And the complexation reaction between the organics with amphoteric functional groups and P204 is the most important step, which controls the kinetic process of FCE. Actually, the bubble masstransfer process strengthened the complexation extraction. The experimental results demonstrate that FCE is shown to be a more effective way of separating and concentrating model compounds than complexation extraction. The essential difference of the FCE and the traditional complexation extraction was investigated.更多还原