Ion transport in natural and engineered membranes: implications for pollutant analysis, toxicity and remediation

水中含有溶解的离子，它们是带电的原子或分子。为了生存，生物体需要能够将一些有益的离子输送到他们的细胞中，并处理有毒的离子。它是水生生物中的生物膜，与水接触，控制溶解离子进出细胞内部的运输。正常的跨膜运输确保了健康的生物体，但如果这种运输中断，可能会导致毒性。同样，通过排除污染物，工程膜也可以用于清洁水域。了解离子在膜上的传输将有助于适当保护水生生物，但实验洞察力也将允许设计用于特定污染物修复的膜，甚至可以选择性和灵敏地检测污染物离子。为此，本研究方案分为三个部分：毒性、分析和修复。 毒性。在我实验室的早期工作中，直接从鱼类中获得了鳃细胞，以研究金属离子的运输。这项拟议的研究计划将转而研究连续细胞系中的培养细胞。有人建议，这种细胞系可能会取代动物试验来评估污染物的毒性。为了使这种测试被接受，有必要评估细胞系来源的细胞在化学上是否与原代培养相似。 分析。在我的实验室中，膜已被用来构建用于分析特定金属离子的离子选择电极。这种电极包括一种离子载体(亲离子化合物)，它只选择性地结合感兴趣的金属离子。作为一种新的监测工具，我建议将离子选择膜构建到监测设备中。用离子选择膜取代现有监测设备中的膜将消除测量物种的任何模糊之处，并可能彻底改变基于膜的监测方法，使其能够广泛用于污染物监测。 补救措施。地表水中磷酸盐(一种带负电荷的离子)浓度升高会造成负面影响，但如果磷酸盐能够被分离出来，它就可以作为一种有价值的肥料产品进行回收。现有的废水处理方法会产生高磷酸盐污泥。将探索使用膜来去除磷酸盐，以从废水污泥中生产化学纯肥料。如果对污泥施加电势，离子就会随着负离子移动到正极而迁移。为了确保回收溶液中只含有磷酸盐，将在处理过的固体和接收电极之间使用一层选择性磷酸盐膜。 总结。该研究计划将是基础研究和应用的结合，提供很好的学习和培训机会，并为水管理中的毒理学、分析和补救问题产生实用的解决方案。

Water contains dissolved ions, which are charged atoms or molecules. For survival organisms need to be able to transport some beneficial ions into their cells, and dispose of toxic ones. It is the biological membranes in aquatic organisms that interface with water and control the transport of dissolved ions to/from the interior of cells. The normal transport across membranes ensures healthy organisms, but if this transport is interrupted toxicity can result. Similarly, engineered membranes can be used to clean waters by excluding pollutants. Understanding the transport of ions across membranes will allow for appropriate protection of aquatic life, but also experimental insights will allow for engineering of membranes for specific contaminant remediation, or even selective and sensitive detection of contaminant ions. To this end, this research proposal is divided into three parts: toxicity, analysis and remediation. TOXICITY. In earlier work in my lab, gill cells were obtained directly from fish to study metal ion transport. This proposed research program will instead investigate cultured cells from continuous cell lines. There is a suggestion that such cell lines might replace animal testing for the assessment of pollutant toxicity. For such testing to be acceptable it is necessary to assess if cell-line derived cells behave chemically similarly to primary cultures. ANALYSIS. In my lab membranes have been used to construct ion selective electrodes for analysis of specific metal ions. Such electrodes include an ionophore (ion-loving compound) that selectively binds only the metal ion of interest. As a new monitoring tool, I propose to build ion-selective membranes into monitoring devices. Replacing membranes in existing monitoring devices with an ion-selective membrane will remove any ambiguity in what species are measured and could revolutionize membrane-based monitoring methods and allow for their wide-spread acceptance for contaminants monitoring. REMEDIATION. Elevated concentrations of phosphate (a negatively charged ion) in surface waters can cause negative impacts, but if the phosphate can be separated it can be recovered as a valuable fertilizer product. Existing wastewater treatment methods result in a high phosphate sludge. The use of membranes to remove phosphate to generate chemically pure fertilizer from wastewater sludge will be explored. If an electric potential is applied to the sludge, the ions will migrate with negative ions moving to the positive electrode. To ensure that the recovery solution include only phosphate a phosphate selective membrane will be used between the treated solids and the receiving electrode. SUMMARY. The research program will be a combination of fundamental studies and applications and provide great learning and training opportunities as well as generating practical solutions to toxicological, analytical and remediation issues in water management.