Use of Ligand-Modified Micellar-Enhanced Ultrafiltration in the Selective Removal of Toxic Metal Ions from Polluted water

该建议涉及去除二价金属离子， 以稀量存在，通过配体从水溶液中 改性胶束强化超滤。 在该方法中， 将表面活性剂分子加入到水溶液中， 浓度超过CMC，使分子形成 胶束 胶束是表面活性剂分子的聚集体， 其中不同分子的非极性链延伸， 堆叠在一起以形成球状疏水核， 围绕核心并保持接触的极性部分 水相。 还向水溶液中加入 金属络合配体，其由亲水性尾和 与金属离子络合的部分。 配体 络合金属离子，并且配体-金属组装体 通过溶解胶束， 疏水性尾部进入膜内部。 水性 然后迫使溶液通过不 允许胶束通过。 因此，金属离子 保留，附着在胶束上，在一个 膜的一侧，并且渗透物含有减少的 离子的水平。 这种分离最吸引人的特点是它的 选择性 配体可以是工程化的， 与特定的金属离子结合。 因此，水溶液 其仅具有一种不希望高浓度离子， 在不浪费材料的情况下， 去除其他离子。 PI和CoPI获得了NSF的资助 1988年开发了该工艺并研究了其选择性。 作为 在提案的“以前的结果”部分中报告 NSF支持”，由先前资助的研究 证明了分离的可行性。 在 特别是在溶液的搅拌单元超滤中， 含有Cu 2 +/Ca 2+的混合物，使用配体NIDA， 优先结合铜离子， 超过90%。 目前的建议扩展了在 先前授予的特定选择性去除二价 Pb 2+、UO 22+、Hg 2+、Cd 2+、Cu 2+、Zn 2+、Ca 2+的合成 新的配体 配体与离子的结合常数，以及 当配体 游离于溶液中并溶解于胶束中。 这些 测量将通过滴定 和透析实验。 超滤实验将在 使用螺旋缠绕膜组件进行。 该提案 注意，这种配置允许对 层流边界层和浓差极化 现象。

This proposal is concerned with removing divalent metal ions, present in dilute amounts, from aqueous solutions by ligand modified micelle enhanced ultrafiltration. In this method, surfactant molecules are added to the aqueous solution in concentrations exceeding the CMC so that the molecules form micelles. Micelles are aggregates of surfactant molecules in which the nonpolar chains of different molecules extend and stack together to form a ball-like hydrophobic core with the polar parts surrounding the core and remaining in contact with the aqueous phase. Also added to the aqueous solution are metal complexing ligands consisting of a hydrophic tail and a moiety which complexes with the metal ion. The ligand complexes the metal ion, and the ligand-metal assembly attaches itself to the micelle by solubilization of the hydrophobic tail into the membrane interior. The aqueous solution is then forced through a membrane which does not allow passage of the micelles. Thus the metal ion is retained, attached to the micelle, in the retentate on one side of the membrane, and the permeate contains a reduced level of the ion. The feature of this separation which is most attractive is its selectivity. Ligands can be engineering which exclusively bind to a particular metal ion. Therefore an aqueous solution that has only one ion at an undesirable high concentration can be cleansed of that ion without wasting materials on the removal of other ions. The PI and CoPIs received an NSF grant to develop the process and study its selectivity in 1988. As reported in the section of the proposal "Results from Prior NSF Support", research supported by the previous grant demonstrated the feasibility of the separation. In particular, in a stirred-cell ultrafiltration of a solution containing a mixture of Cu2+/Ca2+, using the ligand NIDA which binds the copper ion prefentially, rejection of copper was upwards of 90 percent. The present proposal extends the technique developed in the previous grant to the specific selective removal of divalent Pb2+, UO22+, Hg2+, Cd2+, Cu2+, Zn2+ and Ca2+ and synthesizing new ligands. Binding constants of the ligands with ions, and their protination constants will be measured when the ligand is free in solution and solubilized in a micelle. These measurements will be undertaken by a combination of titration and dialysis experiments. Ultrafiltration experiments will be undertaken using a spiral wound membrane module. The proposal remarks that this configuration allows for modelling of the laminar boundary layer, and concentration polarization phenomena.