分离水中低浓度有机溶剂的表面活性萃取技术

This application proposed a novel technique, surface active extraction, to isolate and separate dilute organic solvent dissolved in aqueous solution, which is a kind of universal waste and also very difficult to treat by conventional separation techniques in industry. Since the surface active extraction technique based on the difference of solubility and surface tension, it possessed both the advantages of solvent extraction, which are easy operation and easy scale-up, with the advantages of flotation, which are high efficiency to treat dilute system and low cost. It may be a new solution to treat the waste water or to recover the valuable organics from dilute solution..In this application, the interaction mechanism between extractant molecule and surrounding molecules, which may be water molecule, target organic solvent molecule or the gas molecule, is investigated through the molecular simulation based on quantum chemistry together with the analysis of infrared spectrum, nuclear magnetic resonance spectrum. The surface active extractant is designed according to the acquired mechanism. Then the new extractant is synthesized and its extraction and interface properties are systematically studied. The distribution coefficients under different phase condition and the dynamic coefficients are going to be determined. With the help of computation of fluid dynamics about the different structure of the extractor and flotation column, the surface active extraction technique and the apparatus are developed experimentally with the consideration of high extraction efficiency and low reminiscent extractant micro-emulsions.

低浓度有机溶剂水溶液是工业中常见又难以采用常规分离技术很好处理的体系。本申请提出表面活性萃取技术，通过设计具有高表面活性的萃取剂，将溶剂萃取技术与气体浮选技术耦合，同时利用溶解度、表面活性两种性质差异完成物质分离。该过程既具有溶剂萃取技术的操作简便、技术成熟的优点，也具有气体浮选技术的运行成本低、对低浓度物系分离效率高的特色，针对废水处理、有价物质回收将有广泛的用途。.本申请将采用量子化学计算结合红外光谱、核磁共振波谱的解析，考察萃取剂分子结构与周围环境分子（水分子、目标有机溶剂分子及气体分子）间相互作用规律；在此基础上合成表面活性萃取剂并对其萃取性质、表面性质进行评价；测定表面活性萃取剂相关的热力学、动力学参数，结合流体计算，在萃取器、气浮器上研究工艺操作条件，操作设备形式等对萃取效率、微乳液滴在气泡表面的粘附能力的影响，完成萃取器与气浮器的耦合，为气助溶剂萃取技术的应用提供基础理论。

生产、生活中会产生很多的含低浓度有机物废水，特别是含有机溶剂的工业废水。本申请提出通过氟取代改性现用的萃取剂，制备表面活性萃取剂，通过萃取回收废水中的有机溶剂或有机物，而后通过气泡浮选法回收残留在水相中的表面活性萃取剂。.在对醇类萃取剂的研究中发现，相比正辛醇，氟代后辛醇的萃取能力降低。通过密度泛函理论（DFT）计算比较不同程度氟代的氟代辛醇分子的原子电荷密度分布（NPA）和分子静电势（MEP），结果表明氟代辛醇对苯甲酸的萃取作用位点位于氧原子附近；氟代辛醇的萃取能力随着氟原子取代程度的降低而增强。通过对正辛醇的疏水端进行部分氟代改性后，其在萃取水相中的残留质量比小于百万分之2，可解决因萃取剂在萃取过程中流失而造成的“二次污染”问题，同时采用多级逆流萃取工艺，也能保证氟代萃取剂对目标物的萃取能力。.在对磷酸酯类萃取剂的研究中发现，磷酸三戊酯被氟取代后，其疏水性大大增强，其水中溶解度降低了80.9%，在萃取体系中的溶剂残留降低85.5%，萃取体系中由于溶剂残留造成的CODCr 降低了76.9%。单级萃取率仍然可以达到85%。.氟代稀释剂与氟代萃取剂协同效应研究中发现，C6F12H2与C8H5F13O为正向协萃效应；而C6F14与C8H5F13O有反协萃效应；C6F13H与C8H5F13O的协萃效应随被萃酸浓度的增大，由正向效应变为反向效应。.以气液双膜模型为基础，建立了气液界面吸附与挥发物理模型和数学模型。在过程模拟中，发现这个过程存在多尺度现象，即分子扩散速度（10-9）与气泡宏观运动速度（10-2）尺度存在巨大的尺度差异，这些结果在Fluent与Materials Studio的模拟结果中也得到证实。.经优化后，在自行设计制作的带集沫槽的气浮柱上，采用气泡浮选法回收了难挥发、高表面活性的氟苯。表明适用于表面活性萃取技术的氟取代表面活性萃取剂需要同时具备可以接受的萃取性能和非常低的气相挥发度。