Silver partitioning

Silver occurs naturally in several oxidation states, the most common being elemental silver (Ag°) and the monovalent ion (Ag+). Soluble silver salts are, in general, more toxic than insoluble salts. In natural waters, the soluble monovalent species is the form of environmental concern. Sorption is the dominant process that controls silver partitioning in water and its movements in soils and sediments. As discussed later, silver enters the animal body through inhalation, ingestion, mucous membranes, and broken skin. The interspecies differences in the ability of animals to accumulate, retain, and eliminate silver are large. Almost all of the total silver intake is usually... 

Sorption is the dominant process that controls silver partitioning in water and its movement in soils and sediments. Silver may leach... 

A very important practical case of concentration cell is that in which two electrodes of the same material are immersed in solutions of an electrolyte of different concentrations. Thus, if two silver plates are immersed in solutions of silver nitrate of different concentrations, and are connected by a wire, the metal dissolves in the dilute solution and is precipitated from the strong solution, and this goes on until both solutions have the same concentration. Let us consider a cell containing the solutions of concentration fi, f2 in two chambers A and B, separated by a porous partition, and containing silver plates. When F coulombs pass round the circuit the following changes occur, where n is the migration ratio of the anion ... 

Sanders, J.G. and G.R. Abbe. 1987. The role of suspended sediments and phytoplankton in the partitioning and transport of silver in estuaries. Contin. Shelf Res. 7 1357-1361. 

Shafer, M.M., J.T. Overdier, and D.E. Armstrong. 1998. Removal, partitioning, and fate of silver and other metals in wastewater treatment plants and effluent-receiving streams. Environ. Toxicol. Chem. 17 630-641. 

The conversion of the m-monoolefin to its silver nitrate complex 1 was accomplished by adding 1.66 g. (0.010 mole) of the distilled reaction product to a solution of 1.70 g. (0.010 mole) of silver nitrate in 50 ml. of boiling methanol. The resulting solution, when cooled, deposited the complex as white needles, m.p. 79° dec. recrystallization from methanol separated 1.0 g. of the complex, m.p. 80° dec. After this complex had been partitioned between water and ether, the ether phase was separated, dried over magnesium sulfate, and concentrated. Distillation of the residual liquid in a short path still separated 0.45 g. of the pure (Note 6) cfs-cyclodecene, b.p. 70° (1.0 mm.), n B 1.4852. 

Wasik, S.P. and Tsang, W. Gas chromatographic determination of partition coefficients of some unsaturated hydrocarbons and their deuterated isomers in aqueous silver niUate solutions. J. Phys. Chem., 74(15) 2970-2976, 1970. 

I. 4-methoxyacetophenone (30 //moles) was added as an internal standard. The reaction was stopped after 2 hours by partitioning the mixture between methylene chloride and saturated sodium bicarbonate solution. The aqueous layer was twice extracted with methylene chloride and the extracts combined. The products were analyzed by GC after acetylation with excess 1 1 acetic anhydride/pyridine for 24 hours at room temperature. The oxidations of anisyl alcohol, in the presence of veratryl alcohol or 1,4-dimethoxybenzene, were performed as indicated in Table III and IV in 6 ml of phosphate buffer (pH 3.0). Other conditions were the same as for the oxidation of veratryl alcohol described above. TDCSPPFeCl remaining after the reaction was estimated from its Soret band absorption before and after the reaction. For the decolorization of Poly B-411 (IV) by TDCSPPFeCl and mCPBA, 25 //moles of mCPBA were added to 25 ml 0.05% Poly B-411 containing 0.01 //moles TDCSPPFeCl, 25 //moles of manganese sulfate and 1.5 mmoles of lactic acid buffered at pH 4.5. The decolorization of Poly B-411 was followed by the decrease in absorption at 596 nm. For the electrochemical decolorization of Poly B-411 in the presence of veratryl alcohol, a two-compartment cell was used. A glassy carbon plate was used as the anode, a platinum plate as the auxiliary electrode, and a silver wire as the reference electrode. The potential was controlled at 0.900 V. Poly B-411 (50 ml, 0.005%) in pH 3 buffer was added to the anode compartment and pH 3 buffer was added to the cathode compartment to the same level. The decolorization of Poly B-411 was followed by the change in absorbance at 596 nm and the simultaneous oxidation of veratryl alcohol was followed at 310 nm. The same electrochemical apparatus was used for the decolorization of Poly B-411 adsorbed onto filter paper. Tetrabutylammonium perchlorate (TBAP) was used as supporting electrolyte when methylene chloride was the solvent. 

US EPA (2005). Procedures for deriving equilibrium partitioning sediment benchmarks (ESBs) for the protection of benthic organisms metal mixtures (Cadmium, Copper, Lead, Nickel, Silver and Zinc). EPA-600-R-02-011. Office of Research and Development, Washington, DC 20460. 

Sorption is the dominant process controlling partitioning in water and movement in soil. Silver may leach from soil into groundwater acidic conditions and good drainage increase the leaching rate. Silver is bioconcentrated to a moderate extent in fish and invertebrates. 

Physical and Chemical Properties. No data exist on the partition coefficients and Henry s law constant for silver and its compounds. A vapor pressure has been determined for silver at very high temperatures (greater than 900 °C), but not for any of its compounds. Generally, the fate of silver in the environment is fairly well understood however, a determination of these environmentally... 

Environmental Fate. The factors governing the environmental fate of silver are not well characterized. While silver and its compounds are transported in the air, water, and soil, and are partitioned between these media, the mechanisms of transport and partitioning are not well-defined. No partition coefficients or constants have been determined for silver or its compounds. Little information was found in the available literature on transformation of silver in water or soil. Some microorganisms present in these media may be able to transform silver and silver compounds however, silver is not expected to be significantly transformed in the environment because it is toxic to microorganisms. Further information on the size and flux of environmental compartments and the transport and transformations of silver and silver compounds in the environment would be useful in defining pathways for potential human exposure. 

Thus Mori et al. [303] determined carbofuran by extraction of the soil with acetonitrile containing silver nitrate, partitioning with methylene chloride,... 

Acetonitrile-silver nitrate extracts of soil, partitioned with methylene chloride and cleaned up on silica gel, have been used in the high-performance liquid chromatographic determination of benfuracarb and carbofuran herbicides [204], McGarevy et al. [336] and Lin and Cooper [336] used optimised isocratic high-performance liquid chromatography with UV detection to determine Aldicarb and its metabolites in soil. 

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