The rapid isolation and determination of iridium after simultaneous liquid-liquid extraction and determination of platinum,palladium, rhodium and gold

The proposed method provides a rapid isolation of iridium form the other noble metals, as well as from Ni, Cu, Fe, Cr, Co and Na. The scheme comprises an initial removal of ruthenium and osmium by volatilization of their tetroxides followed by the simultaneous extraction of platinum, palladium, rhodium and gold as their 2-mercaptobenzothiazole—tin(II) chloride complexes into chloroform. Iridium in the raffinate is complexed by the same reagent system, after boiling, and extracted into chloroform. The extracts after evaporation of the solvent are converted to hydrochloric acid solutions and the noble metals are determined by atomic absorption spectrometry. Satisfactory results are obtained for various noble metal solutions, and for a solid platiniferous sample.     

A new solvent extraction scheme for the separation of platinum,palladium, rhodium and iridium

A new scheme is proposed for the separation of platinum, palladium, rhodium and iridium in hydrochloric acid solutions, by solvent extraction. Platinum and palladium are complexed with 2-mercaptobenzothiazole and potassium iodide and simultaneously extracted into chloroform, thus separating them from rhodium and iridium. Palladium is separated from platinum by extracting its dimethylglyoxime complex into chloroform, while rhodium is separated from iridium by extracting its 2-mercaptobenzothiazole complex into chloroform after reduction with tin(II) chloride.     

Extraction of gold, palladium and platinum from chloride, bromide and iodide solution with di-n-octyl sulphide (DOS) in cyclohexane

The extraction of gold, palladium and platinum from hydrochloric acid, hydrobromic acid and iodide media by solutions of di-n-octyl sulphide in cyclohexane was examined. From distribution data it was concluded that the monosolvates AuX(3).DOS and disolvates PdX(2).2DOS are extracted. Extraction of platinum was efficient only from iodide solutions; a disolvate PtI(4).2DOS was formed. The possibility of separation of gold and palladium from platinum by extraction from bromide or chloride solutions and simultaneous extraction of palladium and platinum from an iodide medium was demonstrated.     

Development of Cloud Point Extraction for Simultaneous Extraction and Determination of Platinum and Palladium Using Inductively Coupled Plasma Optical Emission Spectrometry in Platinum-Palladium Spent Catalysts

A new on-line cloud point extraction system coupled to inductively coupled plasma optical emission spectrometry was designed for simultaneous extraction, preconcentration and determination of trace amounts of platinum and palladium in platinum-palladium spent catalysts. This was based on the complexation of the metal ions with 1,8-diamino-4,5-bis(hydroxyamino)anthraquinone reagent in the presence of non-ionic surfactant of Triton X-114. After phase separation, the surfactant-rich phase was diluted with concentrated HNO₃ (70%, w/w); the analytes concentrations were determined by inductively coupled plasma-optical emission spectrometry. Several factors influencing the instrumental conditions and extraction were evaluated and optimized. Under the optimum conditions, the enhancement factors of the proposed method were 35.4 and 29 for platinum and palladium, respectively. The detection limits were 0.3 and 0.45 µ g L^?1. Finally, the developed method was successfully applied to the extraction and determination of platinum and palladium in platinum-palladium spent catalysts samples and satisfactory results were obtained.     

Extraction of palladium and platinum with trioctylphosphine oxide (TOPO) in various solvents from hydrochloric and hydrobromic acid media

The extraction of palladium and platinum with trioctylphosphine oxide (TOPO) in cyclohexane, chloroform, methyl isobutyl ketone (MIBK) and 2,2′-dichlorodiethyl ether (DCDE) from hydrochloric and hydrobromic acids in dependence on the concentration of the acids and the extractant has been investigated. The obtained relation have been discussed and the possibilities of the separation of palladium, platinum, gold and their simultaneous extraction have been pointed out.     

The application of microchemical methods to radiochemical analysis : Part III. Solvent extraction of diethyldithiocarbamates and the radiochemical separation and purification of cobalt,nickel, palladium,silver and cadmium

The advantages of solvent extraction of diethyldithiocarbamatcs in radiochcmical separations are discussed. The development of a procedure for the separation and purification of cobalt and nickel from mixtures containing fission products is described; diethyldithiocarbamate extraction is used extensively. A scheme incorporating this procedure is also described whereby the fission products palladium, cadmium and silver are also determined on the same sample.     

Studies on the extraction of platinum metals with tri-iso-octylamine from hydrochloric and hydrobromic acid: separation and determination of gold, palladium and platinum

The extraction of Pd(II), Rh(III), Ir(III), Au(III) and Pt(IV) from hydrochloric and hydrobromic acid with 5% tri-iso-octylamine solution in carbon tetrachloride has been studied. The gold extract from hydrochloric acid is yellow and absorbs at 325 nm, the palladium compound is red and absorbs at 290 nm and 467 nm, and the platinum compound is blood-red and shows absorption at 268 nm. The gold, palladium and platinum extracts from hydrobromic acid are crimson. reddish brown and blood-red, with maximum absorption at 260, 345 and 300 nm respectively. Methods have been devised for the separation of gold from platinum and for its determination and also for the simultaneous determination of palladium and platinum.     

The analytical chemistry of the pyridine thiocyanates—III The separation of rhodium, palladium and platinum

A procedure is described for the separation and subsequent colorimetric determination of rhodium, palladium and platinum through the formation of complex and ammine-type thiocyanates, using solvent extraction. Suggestions are put forward as to the nature of the complexes in solution.     

Simultaneous Determination of Microgram Amounts of Platinum and Palladium in Presence of Base Metals by Isolation on Anion Exchange Resin-Loaded Paper and X-Ray Spectrometry

Abstract

A procedure for simultaneous determination of microgram amounts of platinum and palladium in solutions of base metals is described. The two metals are isolated on an anion exchange resin-loaded paper disk and determined by X-ray spectrometry. The method is applied to the determination of platinum and palladium in nickel matte.     

Extraction chromatographic separation of platinum(IV) from real samples and associated elements

 The extraction behavior of platinum(IV) was studied with N-n-octylaniline as a function of different parameters, such as pH, concentrations of weak acids, mineral acids, reagents and elution time. A selective method was developed for the extraction chromatographic studies of platinum(IV) and its separation from several metal ions with N-n-octylaniline (liquid anion exchanger) as a stationary phase on silica gel. The quantitative extraction of platinum(IV) was observed with 0.067 mol/L N-n-octylaniline and 0.015 mol/L ascorbic acid at pH 1.0. Metal ion was stripped from the column with water and determined spectrophotometrically with stannous chloride method. The proposed method is free from the interference of a large number of cations and anions. Platinum(IV) was separated from pharmaceutical preparations, alloys and synthetic mixtures. Mutual separation scheme was developed for platinum(IV), palladium(II) and gold(III). The log-log plot of N-n-octylaniline concentration versus the distribution ratio indicates that the probable extracted species is ［RR′NH+2 ］· Pt(C6H7O6)－3.     

Substoichiometric determination of traces of palladium by neutron-activation analysis

A highly selective, rapid one-step radiochemical separation procedure for palladium has been developed. It is based on the solvent extraction of palladium diethyldithiocarbamate from a 5M hydrochloric acid solution with a substoichiometric amount of copper diethyldithiocarbamate in chloroform. The separation has been applied to the determination of traces of palladium by neutron-activation analysis, in platinum, the rocks W-1 and PCC-1 and a biological material (kale). Amounts of palladium down to 10(-8) g have been determined.     

Substoichiometric determination of traces of palladium by radioactive isotope-dilution analysis

A radioactive isotope-dilution method for the determination of traces of palladium has been developed. It is based on the solvent extraction of palladium dithizonate from acid solution by means of a substoichiometric amount of dithizone in carbon tetrachloride. The separation has been applied to the determination of traces of palladium in platinum, the rocks W-1 and PCC-1 and a biological material (kale). Amounts of palladium down to 3 ng have been determined.     

Simultaneous determination of palladium, platinum, rhodium and gold by on-line solid phase extraction and high performance liquid chromatography with 5-(2-hydroxy-5-nitrophenylazo)thiorhodanine as pre-column derivatization regents

In this paper, 5-(2-hydroxy-5-nitrophenylazo)thiorhodanine (HNATR) was synthesized. A new method for the simultaneous determination of palladium, platinum, rhodium and gold ions as metal-HNATR chelates was developed using a rapid analysis column high performance liquid chromatography equipped with on-line solid phase extraction technique. The samples (Water, human urine, geological samples and soil) were digested by microwave acid-digestion. The palladium, platinum, rhodium and gold ions in the digested samples were pre-column derivatized with HNATR to form colored chelates. The Pd-HNATR, Pt-HNATR, Rh-HNATR and Au-HNATR chelates can be absorbed onto the front of the enrichment column when they were injected into the injector and sent to the enrichment column [Zorbax Stable Bound, 10 mm x 4.6 mm, 1.8 microm] with a buffer solution of 0.05 mol L(-1) phosphoric acid as mobile phase. After the enrichment had finished, by switching the six ports switching valve, the retained chelates were back-flushed by mobile phase and travelling towards the analytical column. These chelates separation on the analytical column [Zorbax Stable Bound, 10 mm x 4.6 mm, 1.8 microm] was satisfactory with 72% acetonitrile (containing 0.05 mol L(-1) of phosphoric acid and 0.1% of Triton X-100) as mobile phase. The palladium, platinum, rhodium and gold chelates were separated completely within 2.5 min. Compared to the routine chromatographic method, more then 80% of separation time was shortened. By on-line solid phase extraction system, a large volume of sample (10 mL) can be injected, and the sensitivity of the method was greatly improved. The detection limits (S/N=3, the sample injection volume is 10 mL) of palladium, platinum, rhodium and gold in the original samples reaches 1.4, 1.8, 2.0 and 1.2 ng L(-1), respectively. The relative standard deviations for five replicate samples were 2.4-3.6%. The standard recoveries were 88-95%. This method was applied to the determination of palladium, platinum, rhodium and gold in human urine, water and geological samples with good results.     

钯、铑和铂的同时分光光度测定

贵金属混合物光度分析常需分离,同时测定的报导亦少见。本文提出了一种不用分离,不用萃取,不用解联立方程,灵敏、简便同时分光光度测定三种贵金属的方法。     

New applications of azamacrocyclic ligands in ion recognition, transport and preconcentration of palladium

This work deals with the evaluation of a synthesized 15-membered triolefinic azamacrocycle containing a NH group, (E,E,E)-1,6-bis(p-tolylsulfonyl)-1,6,11-triazacyclopentadeca-3,8,13-triene (R₂NH), for the selective extraction of palladium and platinum from aqueous chloride matrices prior their analysis by ICP-AES. The optimal conditions for liquid–liquid experiments have been evaluated, with special emphasis given to the selection of the organic solvent and the optimal aqueous chloride concentration for the extraction of PdCl₄²⁻ and PtCl₆²⁻. The selective transport and separation of palladium(II) from a mixture of Pd(II) and Pt(IV) was accomplished by means of a supported liquid membrane system containing the macrocycle as carrier dissolved in anethol and 0.5 M thyocianate solution as stripping solution. A C18 cartridge has been activated with the reagent R₂NH in order to test the feasibility of achieving the preconcentration of palladium solutions. Enrichment factors close to the theoretical ones were obtained with the designed system and using thiourea as eluting solution.     

Pt/Pd/C catalysts with ultra low platinum content for oxygen reduction reaction

The activity of Pt/Pd/C ETEK catalysts of the core-shell type with an ultralow content of platinum (0.5–15 μg cm^?2) based on a commercial palladium catalyst is shown to exceed the activity of commercial Pt/C ETEK catalysts in the oxygen reduction reaction. The activity sharply increases with the decrease in the platinum content down to values corresponding to monolayer and submonolayer of platinum on palladium. This dependence wasn’t observed for the same amounts of platinum deposited on the carbon support Vulcan XC-72. This makes it possible to conclude that the most probable factor responsible for the high catalytic activity of Pt/Pd/C ETEK is the effect of palladium on the electronic properties of platinum rather than the effect of structural modification of the platinum deposit induced by the decrease in the platinum amount deposited on a foreign metal or a carbon support.     

Chelate von β-dicarbonylverbindungen und ihren derivaten—teil XLIV. Die extraktion von silber,gold, palladium und platin mit thiodibenzoylmethan1

The extraction of silver(I), gold(III), palladium(II) and platinum(IV) with thiodibenzoylmethane is reported, and methods for the extraction—photometric determination of silver and palladium in trace concentrations are described. Addition of EDTA allows a satisfactory selectivity to be achieved. The influence of foreign metals and complexing agents is discussed.     

Extraction of Palladium(II), Platinum(II), and Platinum(IV) by Bisacylated Diethylenetriamine from Hydrochloric Acid Solutions

The extraction properties of bisacylated diethylenetriamine are studied in the extraction of palladium(II), platinum(II), and platinum(IV) from hydrochloric acid solutions. Optimum extraction parameters are determined. The extraction of metal ions at these parameters follows an ion-associative mechanism. The concentration constants and thermodynamic parameters of extraction reactions are calculated. The feasibility of the extraction separation of palladium and platinum from base metals is verified.     

Neutron activation analysis for iridium,palladium and silver in platinum

A sensitive procedure for the simultaneous determination of trace levels of iridium, palladium and silver in a platinum stock, by thermal-neutron activation analysis utilizing gamma-ray spectrometry, was developed. The radiochemical-separation scheme involved an elution of the chloro complexes of iridium and silver, and subsequently palladium, through a strongly-basic anion-exchange resin, followed by further chemical-separation methods. The ion-exchange method served to greatly reduce the hazard from radiations emitted by the bulk of the activities in the matrix. Activities of 13.5-hr¹⁰⁹Pd, 74.2-d¹⁹²Ir and 255-d^110m Ag were monitored by accumulation of pulses from a 3-in diam. NaI(T1) crystal detector. Further discrimination was attained by resolution of decay curves. The procedure provided analyses for a platinum stock of 0.015±0.0021 ppm Ir; 0.028±0.0043 ppm Pd and 2.4±0.27 ppm Ag.     

The separation of platinum and palladium by selective extraction of H(2)Pt(SCN)(6) and H(2)Pd(SCN)(4) using a polyTHF-impregnated filter

Platinum and palladium are known to form complexes with the thiocyanate ion in solution. The isolation and separation of both platinum and palladium as thiocyanate complexes is demonstrated by passing them through an organic-impregnated filter (OIF) prepared with polyTHF. Simultaneous extraction is performed by converting both metals into the extractable form. Sequential extraction is achieved by exploiting the difference in the rates of formation for the extractable complexes of the two metals. The extraction of both metals is rapid with quantitative recoveries of platinum with flow rates as high as 600 ml min⁻¹ in small samples, while recoveries from larger volume samples were considerably lower. Once extracted, the metals can be removed from the OIF by conversion to a non-extractable form with a high pH eluting solution. The rapid separation, isolation and preconcentration of both platinum and palladium from aqueous samples is demonstrated.