Metal specific sequestering agents

Two fundamental questions in the design of an actinide-specific sequestering agent are the coordination number and geometry actually preferred by the metal ion with a given ligand. The... 

The Synthesis, Thermodynamic Behavior, and Biological Properties of Metal-Ion-Specific Sequestering Agents for Iron and the Actinides... 

The reaction of secondary diamines, carbon disulfide, and alkali metal hydroxides gives bisdithiocarbamate salts, which, upon reaction with bischloro-methylated aromatics, afford soluble polydithiocarbamates (392). The coordination chemistry of these polymers should be investigated. They may prove to be interesting, and, perhaps, specific, metal-sequestering agents. 

Divalent and trivalent transition metal cations (Fe, Cu, Al, Zn, Ni, Cr, etc.) also have several harmful effects, such as flocculation or catalytic destabilization of the bleaching systems that furnish active oxygen, and must, therefore, be eliminated as well. To this end, organic sequestering agents that are more specific to the metallic cations to be removed are used. This subject is, however, on the fringes of the agreed definition of a builder. 

The silicate anion, in all its many forms, has specific properties which make it a valuable component in the various enhanced recovery processes. Among these properties are its ability to sequester multi-valent metal cations to act as a sacrificial agent in the adsorption process by clays to maintain water-wettability to reduce permeability in high permeability areas to improve sweep and to aid in reducing IFT at the oil/water interface. Each of these properties depends on the size, charge, and basicity of the silicate molecule, which can be varied by changing ratio and concentration. 

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