Metal ion recovery

Ion Flotation and Foam Separation. Ions and dissolved surfactant molecules can be removed from solutions by the agency of foam. In this case ions are sandwiched in foam films. The scientific basis of these processes is weU understood and successes of metal ion recovery from solutions including U, Pt, Au, as weU as different surfactants (detergents) have been reported in the Hterature. 

In summary, examination of metal ion recoveries from humic acid samples by different chemical extractants has confirmed that in any extraction procedure very careful consideration must be given to the associated chemical equilibria and the impact of competing reactions. 

Reverse osmosis also serves some of the waste management and resource recovery needs in the metals and metal finishing industry. Effluent streams from mining and plating operations containing heavy metals, acids, and other chemicals can be treated with reverse osmosis to recover both the metal as its salt, and purified water for reuse. For metal ion recovery from dilute solutions, however, reverse osmosis faces competition from conventional solvent extraction, membrane-based solvent extraction, and its variant, coupled transport (see Section V.F.3). 

Metal ion recovery by cementation 21. Green chemistry The recovery and reuse of... 

Prdtsch, M. Marr, R. "Development of a Continuous Process for Metal Ion Recovery By Liquid Membrane Permeation Proceedings Inter. Solvent Extrac. Conf. 1983, pp 66-67. 

These chelating resins have found most of their use in metal ion recovery processes in the chemical and waste recovery industries. They may find use in fermentation applications where the cultured organism requires the use of metal ion cofactors. Specific ion exchange resins have also been used in laboratory applications that may find eventual use in biotechnology product recovery applications. 

The next step towards successful development of the SF extraction process is to move from small-scale investigations to bench scale feasibility studies. Bench-scale data will provide information to evaluate process design issues and to establish the utility of this technology. Key conqwnents of this technology that must be evaluated are (a) ligand solubility in SC COj. (b) metal ion extraction into SC CO2, (c) metal chelate solubility in SC CO2, and (d) metal ion recovery from a metal-laden SC CO2 phase. Hie overall goal of the SFE process is the concentration of the contaminants, as depicted in Hgure 6. 

This overview chapter has the objective of introducing the SyiQ>oslum Series volume and the subject of liquid membrane technology. If membranes are viewed as semi-permeable phase separators, then the traditional concept of membranes as polymer films can be extended to Include liquids and liquid-swollen polymers. The addition of a mobile complexatlon agent to the membrane Is known as facilitated liquid membrane separation. Often, In liquid phase facilitated transport systems, the solute flux Is coupled to the opposite flux of another species. This process, common in metal ion recovery schemes, is known as coupled transport. 

Commercial eind laboratory applications of liquid membrane technology are discussed including gas transport, sensor development, metal ion recovery, waste treatment, biotechnology and biomedical engineering. Immobilized liquid membranes, emulsion or liquid surfactant membranes, and membrane reactors are discussed. Economic data from the literature for liquid membrane processes are presented and compared with existing processes such as solvent extraction and cryogenic distillation of air. 

Maureira, A., Rivas, B.L., Metal ions recovery with alginic acid coupled to ultrafiltration membrane, Eur. Polym. J. 45, 573, 2009. 

Hydrogels show a marvelous prospect for the procedure of metal-ions recovery from dilute solutions (Peter 1995, Varma et al. 2004). Recently, the adsorption of natural organic pollutants (such as humic acids) from aqueous solution using chitosan adsorbents has attracted intensive attention in environment and health fields (Ngah and Musa 1998, Wu et al. 2002, Yan and Bai 2005). Adsorbents, derived from a nature polymer, are required for environment-conscious technologies. The adsorptions of metal ions and humic acid from aqueous solutions onto radiation cross-linked chitosan derivatives were introduced here. 

A detailed analysis shows that the mechanism of metal ion recovery as a result of pH perturbation is different in water and in SDS micellar solution. The kinetics of dissociation of Ni(2-methyl-8-hydroxyquinoline) by H have also been studied in aqueous and micellar solutions of the ionic surfactants SDS and CTAN (cetyltrimethylammonirun nitrate) and of the nonionic surfactants Triton X-100 and Brij 35. Activation parameters were the same in water and neutral micelles, but very different in SDS and CTAN. The ratedetermining step was claimed to be dissociation of the NiL" complex at the micelle-water interface. 

Silica Polyamine Composites Advanced Materials for Metal Ion Recovery and Remediation... 

PFSA membranes have excellent chemical inertness and mechanical integrity in a corrosive and oxidative environment, and their superior properties allowed for broad application in electrochemical devices and other fields such as superacid catalysis, gas drying or humidification, sensors, and metal-ion recovery. Here, we refer their important applications in electrochemical devices for energy storage and conversion including PEMFC, chlor-alkali production, water electrolysis, vanadium redox flow batteries, lithium-ion batteries (LIBs), and solar cells. 

In other work designed to prepare and test ion exchange materials for metal ion recovery and oxidation-reduction properties (3), we had occasion to prepare a series of polythiosemicarbazides The initial compounds worked with were prepared as follows ... 

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