Trace metals recovery from water

Hitchon B., Perkins E. H., and Gunter W. D. (2001) Recovery of trace metals in formation waters using acid gases from natural gas. A/)/)/. Geochem. 16, 1481-1497. 

Figure 10.37 Precision and recovery data for Trace Metals in Drinking Water Certified Reference Material (CRM) by ICP-MS. The ICP-MS used was a PE SCIEX Elan 6000 and the CRM is from High Purity Standards, Charleston, SC. (From Wolf et al. 1995, used with permission.)...

A very important practical and environmentally beneficial aspect of the use of a separate aqueous phase in catalytic reactions producing water-insoluble products is the potential for relatively easy and complete recovery of water-soluble catalysts. This could lead to the elimination of further steps for removal of traces of heavy metal from the product and to considerable savings. ... 

If the mo is correct, the recovery in the unknown matrix is satisfactory, and a satisfactory pyrolysis temperature has been determined the rest is detail. We try to use NIST materials to confirm a method and to build confidence. We use NBS 1643, Trace Metals in Water, as a further test of our standards. Also remember that small volumes of solution left in a room environment change concentrations rapidly in both directions because of solvent evaporation and contamination from settling dust. 

There are several reasons for performing speciation. Of course there are the academic studies of various types of trace metals and their conversion and equilibria of various forms. Industrial speciation is important. The effectiveness of chromium plating baths depends on the amounts of Cr(III) and Cr(VI) that are present. Gold plating processes involve the use of Au(I) and Au(III) cyanide complexes. Vanadium speciation is important in the recovery of sulfur from geothermal water. 

Thirty-four minor and trace elements are of potential environmental concern (n ). Sulfur is the element of major concern due to its abundance in flue gases from some coal-burning plants and its subsequent contribution to "acid rain." Sulfur as acidic ions of sulfate can also contribute to pollution of surface water and groundwater. Other elements of greatest concern are As, B, Cd, Pb, Hg, Mo, and Se. With the exception of B and Se, these elements are strongly associated with mineral matter in the coal and are concentrated in waste piles from coal preparation plants. If the waste disposal site is not constructed as a closed system, pollution of nearby groundwater is possible. Boron and Se may contribute to the pollution risk as they are associated with both mineral and organic components. On the other hand, certain coal-mine wastes have potential for recovery of valuable metals such as zinc and cadmium (18). 

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