Platinum group elements solubility

S. Caroli, A. Alimonti, F. Petrucci, B. Bocca, P. Schramel, M. Zischka, C. Pettersson, U. Wass, M. Luna, J. C. Saenz, J. SantamarEnvironmental risk of particulate and soluble platinum group elements released from gasoline and diesel engine catalytic converters, Sci. Total Environ., 296 (2002), 199D208. 

Ruehle T, Schneider H, Find J, Herein D, Pfaender N, Wild U, Schloegl R, Nachtigall D, Artelt S, Heinrich U (1997) Preparation and characterisation of Pt/A1203 aerosol precursors as model Pt-emissions from catalytic converters. Appl Catal B Environ 14 69-84 Schafer J, Hannker D, EckWdt JD, Stiiben D (1998) Uptake of traffic-related heavy metals and platinum group elements PGE by plants. Sci Total Environ 215 59-67 Speranza A, Leopold K, Maier M, Taddei AR, Scoccianti V (2009) Pd-nanoparticles cause Increased toxicity to kiwifruit pollen compared to soluble Pd. Environ Pollut (submitted) Sures B, Zimmermann S (2007) Impact of humic substances on the aqueous solubility, uptake and bioaccumulation of platinum, palladium and rhodium in exposure studies with Dreissena polymorpha. Environ Pollut 146(2) 444 51... 

Moldovan M, Rauch S, Gomez M, Palacios M, Morrison GM (2001) Bioaccumulation of palladium, platinum and rhodium fixrm urban particulates and sediments by the freshwater isopod Asellus aquaticus. Water Res 35 4175-4183 Moldovan M, Palacios MA, Gomez MM, Morrison G, Rauch S, McLeod C, Ma R, Caroli S, Alimonti A, Petrucci F, Bocca B, Schramel P, Zischka M, Pettersson C, Wass U, Luna M, Saenz JC, Santamarfa J (2002) Environmental risk of particulate and soluble platinum group elements released from gasoline and diesel engine eatalytic converters. Sci Total Environ 296 199-208... 

A An answer to this question may be found by consulting Chapters 25, 26, 27 and 28 in the first edition of Chemistry of the Elements, by N. N. Greenwood and A. Earnshaw (1984). A possible separation process which exploits the differing reactivities and solubilities of the platinum group metals (Box l.l) is shown in Scheme 1.1. 

Numerous elements form multicharged anionic complexes which are able to associate with hydrophobic basic dyes. They include anions of the heteropoly acids of Si, Ge, P(V), and As(V), the bromide complexes of Bi and Te(IV), and the thiocyanate complexes of Mo and W. Flotation of sparingly soluble ion-associates formed between the multicharged anionic complexes (with halides, SnC, and thiocyanate) of the platinum-group metals and... 

Rubeanic acid (I) reacts in ammoniacal solution in its aci-form (II) with copper, cobalt and nickel salts giving insoluble colored compounds (see page 329). In solutions containing strong mineral acid, rubeanic acid reacts only with certain elements of the platinum group. With palladium and platinum salts, red crystalline precipitates are obtained they are inner complex salts (III) of a semi-aci-form of rubeanic acid. Ruthenium salts give a soluble blue compound, whose structure is not known. 

The most widely used method for adding the elements of hydrogen to carbon-carbon double bonds is catalytic hydrogenation. Except for very sterically hindered alkenes, this reaction usually proceeds rapidly and cleanly. The most common catalysts are various forms of transition metals, particularly platinum, palladium, rhodium, ruthenium, and nickel. Both the metals as finely dispersed solids or adsorbed on inert supports such as carbon or alumina (heterogeneous catalysts) and certain soluble complexes of these metals (homogeneous catalysts) exhibit catalytic activity. Depending upon conditions and catalyst, other functional groups are also subject to reduction under these conditions. 

Platinum is classed by tradition and commercial usefulness as a precious metal that is soft, dense, dull, and silvery-white in color, and it is both malleable and ductile and can be formed into many shapes. Platinum is considered part of the precious metals group that includes gold, silver, iridium, and palladium. It is noncorrosive at room temperature and is not soluble in any acid except aqua regia. It does not oxidize in air, which is the reason that it is found in its elemental metallic form in nature. Its melting point is 1,772°C, its boiling point is 3,827°C, and its density is 195.09g/cm. ... 

The TcAl6 phase was shown to be isoslructural with MnAlf, and ReAle- TcAli2 exhibits the same structure as M0AI12 and ReAli2 [51]. No new intermediate phases were found to exist in alloys of technetium with rhodium, palladium or platinum. The solubility of technetium in these metals increases in the given sequence ]71]. The group Vlll transition elements Co, Ni, Rh, Pd, Ir. and Pt show extensive solid solubility in technetium metal at 1050 "C [72]. The solid solubility of technetium in nickel is... 

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