Selective and Regenerable Metal Sorbing Vesicles for Metal Ion Recovery

用于金属离子回收的选择性和可再生金属吸附囊泡

• 批准号: 9525019
• 负责人: Harold Monbouquette
• 金额: $ 21万
• 依托单位: University of California-Los Angeles
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 1995
• 资助国家: 美国
• 起止时间: 1995-10-01 至 1999-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9525019&HistoricalAwards=false
• 关键词: Selective; Regenerable; Metal; Sorbing; Vesicles

CTS-9525019 Monbouquette UCLA The central goal of this research is to demonstrate the feasibility of novel metal-sorbing vesicle media for the selective recovery of toxic heavy metal ions, such as Cu2+, Cd2+ and Pb2+, from dilute aqueous solution in a continuous process. Metal-sorbing vesicles, which are submicron-diameter, surfactant bilayer membrane capsules, have been engineering to scavenge and to concentrate metal ions by virtue of a lipophilic metal carrier in the vesicle wall and a water-soluble, meal-chelating agent dissolved in the aqueous vesiclle interior. The carrier facilitates transport of the charged metal ion across the otherwise impermeable lipiid bilayer while the encapsulated chelating agent provides the driving force for metal ion uptake. Batch results show that suspensions of engineered metal-sorbing vesicles, which present 103-104m2 of surface area per liter of suspension, can selectively reduce Pb2+ or Cu2+ concentrations from 1-5 ppm to low ppb levels in minutes or less while concentrating the metal by 3 orders of magnitude. These results were used to design a bench-scale continuous metal-ion extractin process where the vesicles and the feed stream were contacted using a hollow-fiber ultrafiltration cartridge. Lead ions were selectivly separated in this continous systems, which was described well by a simple mathematical model. However, this continuous system did not include a vesicle regeneration stage for metal ion release such that the vesicles could be reused repeatedly. During the proposed three-year project, this separations technology will be brought forward in three areas critical to the establishment of technical feasibility: design for selectivity, continous processing with vesicle regeneration, and vesicle stability enhancement. The overall selectively of the metal-sorbing vesicle depends in a non-additive way on the relative affinity of both carrier and chelator for the ions present in solution. A proposed qualitative model of this fundamentally new mechanisms in separations shows that the overall systems can be orders of magnitude more selective than the carrier or chelator alone if their selectivity profiles are properly matched. The selectivity of vesicles harboring carefully chosen carrier and chelator pairs will be determined to confirm the qualititative model of metal-sorbing vesicle selectivity. As for vesicle reusability, preliminary data indicates that metal-laden vesicles can be regenerated in minutes at slightly elevated temperature and a moderate pH of 2.0. A metal-sorbing vesicle regeneration process will be further investigated, optimized and integrated into a bench-scale continuous metal-ion recovery system. A descriptive mathematical model of the system, useful for process design, will be constructed and tested by comparison to experimental results. Finally, polymerized vesicles of various chemistry will be tested for improved stability at the elevated levels of detergent, alcohols, and Ca2+ ions, for example, that could be encountered in an actual process stream. Coupled to this study will be an assessment of the permeability and regenerability properties of the polymerized vesicles, as these properties have a direct impact on the efficacy of the proposed continuous metal recovery systems. Currently there is no data available in the literature on carrier mediated transport across polymerized vesicle bilayers.

CTS-9525019 Monbouquette UCLA 本研究的中心目标是证明新型金属吸附囊泡介质的可行性，用于选择性回收有毒重金属离子，如Cu 2+，Cd 2+和Pb 2+，从稀水溶液中的连续过程。 金属吸附囊泡是亚微米直径的表面活性剂双层膜胶囊，已被设计用于通过囊泡壁中的亲脂性金属载体和溶解在水性囊泡中的水溶性膳食螯合剂来清除和浓缩金属离子。内部。 载体促进带电金属离子穿过原本不可渗透的脂质双层的运输，而封装的螯合剂为金属离子吸收提供驱动力。 批量结果显示，每升悬浮液具有103- 104 m2表面积的工程化金属吸附囊泡的悬浮液可以在几分钟或更短的时间内将Pb 2+或Cu 2+浓度从1-5 ppm选择性地降低到低ppb水平，同时将金属浓缩3个数量级。 这些结果被用来设计一个实验室规模的连续金属离子提取过程中的囊泡和进料流接触使用中空纤维超滤盒。 在该连续体系中，铅离子被选择性地分离，并用一个简单的数学模型进行了描述。 然而，该连续系统不包括用于金属离子释放的囊泡再生阶段，使得囊泡可以重复使用。在拟议的三年项目期间，将在对建立技术可行性至关重要的三个领域提出这种分离技术：选择性设计、囊泡再生连续处理和囊泡稳定性增强。 金属吸附囊泡的总体选择性以非加和的方式取决于载体和螯合剂对溶液中存在的离子的相对亲和力。 一个拟议的定性模型，这从根本上是新的机制在分离表明，整体系统可以是数量级的选择性比单独的载体或螯合剂，如果他们的选择性配置文件是适当匹配。 将确定具有精心选择的载体和螯合剂对的囊泡的选择性，以确认金属吸附囊泡选择性的定性模型。 至于囊泡的可重复使用性，初步数据表明，载金属囊泡可以在稍微升高的温度和2.0的中等pH值下在几分钟内再生。 一个金属吸附囊泡再生过程将进一步研究，优化和集成到一个实验室规模的连续金属离子回收系统。 一个描述性的数学模型的系统，有用的工艺设计，将构建和测试的实验结果进行比较。 最后，将测试各种化学性质的聚合囊泡在例如实际工艺流中可能遇到的较高水平的去污剂、醇和Ca 2+离子下的改进的稳定性。 与本研究相结合的是对聚合囊泡的渗透性和可再生性的评估，因为这些性质对所提出的连续金属回收系统的功效有直接影响。 目前，在文献中没有关于载体介导的跨聚合囊泡双层转运的数据。