Separation of the non-volatile noble metals by reversed-phase extraction chromatography.
The procedure involves the use of tri-n-butyl phosphate (TBP) adsorbed by Porasil C and stepwise elution with sulphuric acid and hydrochloric acid. The distribution coefficients for the two systems (TBP and hydrochloric acid and TBP and sulphuric acid) and the elution characteristics were studied. A description is given of a procedure applicable to the analysis of prills obtained from the fire assay of platinum-bearing ores.
Ion-exchange resins in non-aqueous solvents-III Solvent-uptake properties of ion-exchange resins and related adsorbents.
Solvent-uptake properties for several synthetic resins and common adsorbents were determined by the centrifugation method. Data are reported for eighteen different solvents, which include water and the common polar and non-polar organic solvents. The cation-exchange resins are of two varieties: the microreticular or gel type and the macroreticular or porous type. The latter resin being rigid and porous takes up all types of solvents, whereas the former resin, which relies on swelling of the resin matrix, does not take up the nonpolar solvents. Data for the H(+) form and Na(+) form macroreticular resin are compared. Unsulphonated polystyrene-divinylbenzene polymers which possess similar micro- and macroreticular properties to the cation-exchange resins were also studied in the same solvents. The swelling properties of these non-polar resins are compared with each other and with the polar cation resins. Other adsorbents, which are frequently used as supports in chromatography were also examined in the same solvents. Several of these have large average pore diameters and surface areas like the macroreticular resin.
The solution chemistry of rhodium(III) IN 6 N HCl
Abstract On the evidence of absorption spectra and adsorption on a Dowex-2 column rhodium chloride or rhodium hydroxide heated in 6 N HCl at 110° reaches equilibrium in approximately one hour. At equilibrium approx. 95% of the rhodium is in the form of hexachlororhodate(III), probably with a small amount of polynuclear chlororhodium complexes but apparently negligible amounts of aquo-chloro-complex anions. During the heating of rhodium hydroxide in 6 N HCl the intermediate formation of quite stable aquo-chloro complexes was demonstrated by isolation on Dowex-2 columns and determination of their absorption spectra.