Influence of the Degree of Chitosan Sulfoethylation on the Sorption of Palladium(II) Chloride Complexes from Multicomponent Solutions

The influence exerted by the degree of substitution of sulfoethylated chitosan cross-linked with glutaraldehyde on the sorption of Pd(II) chloride complexes from multicomponent solutions containing Pt(IV), Cu(II), Ni(II), Co(II), Cd(II), and Zn(II) was studied. The sorption of transition metal ions under the conditions of the experiment at pH 0.5–5.0 is virtually fully suppressed. The strongest interfering effect on the Pd(II) sorption is exerted by Pt(IV). Calculation of the selectivity coefficients K_Pd/Pt shows that the selectivity of the Pd(II) sorption relative to Pt(IV) increases with an increase in the degree of substitution of chitosan from 0.3 to 0.5. Integral kinetic curves of the Pd(II) sorption were obtained, and the dependences were subjected to mathematical processing using the models of diffusion and chemical kinetics. The equilibrium in the palladium(II) chloride solution–sorbent system is attained within 40 min. Pd and Pt are quantitatively desorbed from the sorbent surface under dynamic conditions with 3.5 M HCl solution.     

Preconcentration and separation of trace Pd(II) and Pt(IV) with silica gel bonded by aminopropyl-benzoylazo-4-(2-pyridyl-azo)-resorcinol

This paper reports a simple and highly selective method for preconcentrating and separating of trace Pd(II) and Pt(IV) with silica gel bonded by aminopropyl-benzoylazo-4-(2-pyridy-lazo)-resorcinol (ABPR-SG). ABPR-SG is stable in solution from 6 mol/L HCl to pH 7.0 and in common organic solvents. The maximum adsorptive capacity of Pd(n) on ABPR-SG is 362 μmol/g. After preconcentration and separation by using ABPR-SG column, Pd(II) and Pt(IV) of μg/L level in artificial water samples can be measured reliably by common spedrophotometry. The maximum concentration factors of Pd(II) and Pt(IV) on ABPR-SG column are 143 and 125 respectively. The chromatographic column packed with ABPR-SG can be reused. The method is simple and efficient.     

MEKC determination of vanadium from mineral ore and crude petroleum oil samples using precapillary chelation with bis(salicylaldehyde)tetramethyl‐ethylenediimine

An analytical procedure has been developed for the separation of Cu(II), Ni(II), Co(II), Fe(II), Pd(II), Th(IV), V(IV), and determination of Fe(II), Co(II), Ni(II), and V(IV) by MEKC after chelation with bis(salicylaldehyde)tetramethylethylenediimine (H₂SA₂Ten). Uncoated fused silica capillary was used with an applied voltage of 30 kV with photo‐diode array detection at 228 nm. SDS was added as micellar medium at pH 8.2 with sodium tetraborate buffer (0.1 M). Linear calibrations were established within 0.015–1000 μg/mL of each element with LOD within 5–67 ng/mL. The method was applied for the determination of vanadium from crude oil and ore samples in the range 0.34–2.40 and 114.2–720.7 μg/g with RSD 1.7–3.8 and 0.98–2.30% (n = 3), respectively. Fe, Ni, and Co present in crude oil and ore samples were also determined with RSD 1.3–2.8, 1.1–4.1, and 1.2–3.5% (n = 3), respectively. The results were compared with that of supplier's specifications and atomic absorption spectrometry (AAS). Method was evaluated by standard addition technique.     

Synthesis of N-Methyl-2-Thioimidazole Resin and Its Complex Behavior for Noble Metal Ions

The functional group capacity and the percentage of functional group conversion of crosslinked polystyrene resin bearing N-methyl-2-thioimidazole (MTIR) synthesized under optimum conditions are as high as 4.08 mmol/g resin and 96.0%, respectively. The apparent activation energies of sorption of MTIR for Au(III) and Pt(IV) are 13.1 and 13.4 kJ/mol, respectively. The sorption behavior of MTIR for Au(III), Pt(IV), and Pd(II) obeys the Freundlich and Langmuir isotherms. The sorption capacities of MTIR for Au(III), Pt(IV), and Pd(II) are as high as 4.33, 2.12, and 2.33 mmol/g resin, respectively. Au(III), Pt(IV), and Pd(II) adsorbed on MTIR can be eluted quantitatively by the eluant. The resin can be regenerated easily and reused without an obvious decrease in the sorption capacity for Au(III) and Pd(II). The resin has high sorption selectivity for noble metal ions. Au(III) can be separated quantitatively in the presence of high concentrations of Cu²⁺, Fe³⁺, Ni²⁺, and Mn²⁺. The recovery of platinum from the spent industrial catalysts is 98.6% by MTIR. The preconcentration and separation of palladium and platinum from the anode deposits of electrolysis of crude copper have been investigated. The resin may have potential industrial uses.     

Sorption of palladium(II), rhodium(III), and platinum(IV) on Fe(3)O(4) nanoparticles

The adsorption of palladium(II), rhodium(III), and platinum(IV) from diluted hydrochloric acid solutions onto Fe(3)O(4) nanoparticles has been investigated. The parameters studied include the contact time and the concentrations of metals and other solutes such as H(+) and chloride. The equilibrium time was reached in less than 20 min for all metals. The maximum loading capacity of Fe(3)O(4) nanoparticles for Pd(II), Rh(III), and Pt(IV) was determined to be 0.103, 0.149, and 0.068 mmol g(-1), respectively. A sorption mechanism for Pd(II), Rh(III), and Pt(IV) has been proposed and their conditional adsorption equilibrium constants have been determined to be logK=1.72, 1.69, and 1.84, respectively. Different compositions of eluting solution were tested for the recovery of Pt(IV), Pd(II), and Rh(III) from Fe(3)O(4) nanoparticles. It was found that 0.5 mol L(-1) HNO(3) can elute all of the metal ions simultaneously, while 1 mol L(-1) NaHSO(3) was an effective eluting solution for Rh(III), and 0.5 mol L(-1) NaClO(4) for Pt(IV). In competitive adsorption, the nanoparticles showed stronger affinity for Rh(III) than for Pd(II) and Pt(IV).     

1-(2-氨乙基)吡咯烷树脂的合成及其对贵金属的吸附

研究了试剂摩尔比、反应温度、反应时间对1-(2-氨乙基)吡咯烷树脂合成的影响规律.此树脂的功能基含量2.74 mmol/g树脂,对Au(Ⅲ)、Os(Ⅳ)、Pt(Ⅳ)、Ir(Ⅳ)、Ru(Ⅲ)、Pd(Ⅱ)的吸附容量分别高达950、520、436、418、314、302 mg/g树脂.FT-IR、元素分析表征了树脂结构.测定了吸附速率曲线,配位比,表观吸附活化能△E_(Au)=6.4、△E_(Pt)=33.7kJ/mol.XPS研究了吸附机理.     

Pyrimidinethiol as a reagent for extraction separation of platinum metals and gold Determination of Pd(II), Os(VIII) and Ru(III)

The solvent extraction separation of Pt(IV), Pd(II), Os(VIII), Ru(III) and Au(III) from one another and also from Rh(III) and Ir(III) with 1-(2'-nitro-4'-tolyl)-4,4,6-trimethyl-(1H, 4H)-2-pyrimidinethiol has been investigated. Photometric procedures have been developed for the determination of Pd(II), Os(VIII) and Ru(III) with the same reagent. The reagent allows the enrichment of Pd(II) and Au(III) at the trace level from a large volume of aqueous medium even in the presence of base metals. The method can be used for the determination of platinum metals and gold in alloys.     

Investigation of the usefulness of NTA, EDTA and DTPA in separation of some platinum metals on cellulose exchangers

The possibility of using NTA, EDTA and DTPA as complexing agents for separation of some platinum group ions on cellulose ion-exchangers has been investigated. The greatest differences in the affinities of Pd(II) and Pt(IV) toward the cellulose ion-exchangers are obtained in the presence of DPTA, Cellex D (as ion-exchanger) in hydroxide form. The column separation of Pd(II) from Pt(IV), Rh(III) from Pd(II) and of a Rh(III)Pd(II)Pt(IV) mixture can be achieved with DPTA and chloride solutions. The method can be for determination of the components of RhPdPt alloys.     

<Emphasis Type="Italic">N</Emphasis>-(2-(2-Pyridyl)ethyl)chitosan (PEC) for Pd(II) and Pt(IV) sorption from HCl solutions

Chitosan was modified by grafting 2-pyridyl-ethyl moieties on the biopolymer backbone for the synthesis of a Platinum Group Metal (PGM) sorbent. The sorbent was tested for Pd(II) and Pt(IV) sorption from HCl solutions. Stable for HCl concentrations below 0.5 M, the sorbent reached sorption capacities as high as 3.2 and 2.6 mmol metal g⁻¹ for Pd(II) and Pt(IV), respectively. Metal sorption mainly proceeds by electrostatic attraction in acidic solutions, though a contribution of complexation mechanism cannot be totally rejected. The resistance to intraparticle diffusion is the main controlling mechanism for uptake kinetics. While agitation speed has a limited effect on kinetics, metal concentration and sorbent dosage have a greater effect on the kinetic profiles. The intraparticle diffusivity varies between 3 × 10⁻¹¹ and 4.5 × 10⁻¹⁰ m² min⁻¹. Thiourea (combined with HCl solution) is used for Pd(II) and Pt(IV) desorption. The resin could be desorbed and recycled for a minimum of five cycles maintaining high efficiencies of sorption and desorption.     

Complexing of Pd(II) and Pt(II) by dithiooxamide immobilized on SiO2

It is shown that dithiooxamide immobilized on SiO₂ can bind Pd(II) and Pt(II) from aqueous chloride solutions by complexing. Values have been derived for the effective Pd(II) and Pt(II) sorption constants for dithiooxamide immobilized on SiO₂, which represent stronger binding of Pd(II) than Pt(II). L. V. Pisarzhevskii Institute of Physical Chemistry, National Academy of Sciences of Ukraine, 31 Prospekt Nauki, Kiev 252039, Ukraine. Translated from Teoreticheskaya i éksperimental'naya Khimiya, Vol. 34, No. 6, pp. 366–370, November–December, 1998.     

Sorption Selectivity of Palladium(II) by Poly(N-2-Sulfoethylallylamine) under Static and Dynamic Conditions

Russian Journal of Applied Chemistry - The process of Pd(II) sorption from hydrochloric acid solutions was studied in the pH range of 0.5–5.0 in the presence of Pt(IV) and a number of...     

Amorphous and ordered organosilicas functionalized with amine groups as sorbents of platinum (II) ions

Two groups of amine-functionalized organosilicas have been synthesized: amorphous polysiloxane xerogels (APX) and ordered mesoporous organosilicas (OMO) by co-condensation of tetraethoxysilane and appropriate alkoxysilanes: aminopropyltriethoxysilane and N-[3-(trimethoxysilyl)propyl]ethylenediamine. The obtained materials were characterized by sorption measurements, X-ray diffractometry, elemental analysis, transmission electron microscopy, and scanning electron microscopy. The OMO samples have well developed porous structure—the values of specific surface area are in the range 740–840 m²/g. While the APX samples are less porous having the corresponding values in the range 280–520 m²/g. The sizes of the ordered mesopores of OMO are in the range 5.9–6.5 nm while for the APX they are 2.9–12.1 nm indicating structural differences between both groups of the samples. All samples were tested as the sorbents of Pt(II) ions. The influence of various parameters such as pH, contact time, equilibrium concentration on Pt(II) adsorption ability onto prepared adsorbents was studied in detail. Additionally, the effect of chloride concentration on Pt(II) adsorption was investigated. The values of static sorption capacities were in the range of 32–102 mg_Pt(II)/g and 20–139 mg_Pt(II)/g for OMO and APX series, respectively.     

Determination of platinum (II,IV) and palladium(II) as thiocyanate complexes by capillary zone electrophoresis analysis of carboplatin and similar drugs

The thiocyanate complexes of Pd(II), Pt(II) and Pt(IV) were studied by capillary zone electrophoresis. Pd(II) can be detected in the form of the thiocyanate complex at 305 nm with higher sensitivity than in the form of its chloro complex (absorption maximum 214 nm). A detection limit equal to 5 ppb for Pd has been finally achieved. The possibility of simultaneous determination of Pd(II) and Pt(IV) in the form of thiocyanate complexes has also been demonstrated. When the method optimized for the determination of Pt(II) was applied to the drugs Cykloplatin and Ribocarbo (containing carboplatin) and Platidiam (containing cisplatin), good agreement of the platinum content with the declared value was obtained. Samples of vehicle exhaust particulates (National Institute for Environmental Studies, Japan, No. 8 reference material) were also analyzed.     

Separation and determination of small amounts of palladium and platinum

Summary A procedure is described for the separation of 20 to 100g of Pd(II) from 100 to 300g of Pt(IV) in a mixture. The method is based on the selective separation of Pd(II) on silica gel, leaving Pt(IV) in the solution phase. Complete recovery of Pt(IV) in the supernate has been checked with¹⁹⁷Pt as the radioactive indicator. The deposited palladium is extracted with dil. HCl, and the separated components are determined spectrophotometrically. A possible mechanism has been suggested.

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Zusammenfassung Die Trennung eines Gemisches aus 20 bis 100g Pd(II) und 100 bis 300g Pt(IV) wurde beschrieben. Sie beruht auf der selektiven Adsorption von Pd(II) an Kieselgel. Das vollständige Verbleiben von Pt(IV) in der Lösung wurde mit¹⁹⁷Pt radiochemisch erwiesen. Das adsorbierte Pd wird mit verd. HCl extrahiert und spektrophotometrisch gemessen. Eine mögliche Interpretation des Adsorptionsvorganges wird angeführt.

     

Highly efficient adsorbing noble metal ions by 3,4-dihydroxycinnamic acid-modified activated carbon

A method was established for the preconcentration of trace Au(III), Pd(II) and Pt(IV) by activated carbon modified with 3,4-dihydroxycinnamic acid. The separation and preconcentration conditions of analytes were investigated, such as effects of pH, the contacting time, the sample ?ow rate and volume, the elution condition and the interfering ions. At a pH of 1.0, the maximum static sorption capacity of the sorbent was found to be 374.8, 96.6 and 137.5 mg g^?1 for Au(III), Pd(II) and Pt(IV), respectively. The adsorbed metal ions were effectively eluted with 2.0 mL of 4% thiourea in 0.5 M HCl solution and determined by inductively coupled plasma optical emission spectrometry. The detection limit (3σ) of this method defined by IUPAC was found to be 0.12, 0.18 and 0.32 ?g L^?1 for Au(III), Pd(II) and Pt(IV), respectively. The relative standard deviation (RSD) was lower than 3.0% (n = 8) towards standard solutions. The method has been validated by analysing certified reference materials and successfully applied to the determination of trace Au(III), Pd(II) and Pt(IV) in road sediments samples.     

Synthesis of Functional Resins Containing Heterocyclic Rings and Their Sorption Properties for Noble-Metal Ions

Five kinds of functional resins, 2-aminopyridine resin (2-APR), 3-APR, 4-APR, 2-hydroxypyridine resin (2-HPR), and 2-thiolbenzothiazole resin (2-TBTR), were synthesized. The functional group capacities of the resins were 3.0–4.2 mmol/g resin. The sorption capacities of 4-APR, 3-APR, and 2-APR for Au(III) and Pt(IV) were 3.12–3.22 mmol Au(III)/g APR and 1.27–1.60 mmol Pt(IV)/g APR. The molar complex ratios, Au(III)/NH-C₅H₄N and Pt(IV)/NH-Cs H₄N were 0.84–0.97 and 0.34–0.48, respectively. Selective sorption of 4-APR for various coexistent metal ions over a wide acidity range (1–5 N HCl) was in the following order: Pt(IV) > Au(III) > Cd²⁺ > Zn²⁺ > Pd(II) > Mn²⁺, Cu²⁺, Fe³⁺. The Au(III) adsorbed on APR can be quantitatively eluted with 2% aqueous thiourea. The regenerated APR can be reused without apparent decrease in the sorption capacity for Au(III). The separation of Au(III) and Cu²⁺ was studied preliminarily. The excellent properties show that APR may be used in the gold industry. The sorption capacities of 2-HPR for Au(III) is 0.99 mmol Au(III)/g 2-HPR. That of 2-TBTR for Au(III) is less than that of APR. 2-HPR is stable below 100°C, while 4-APR and 2-APR are stable below 80°C in air.     

Determination of platinum and palladium in road dust after their separation on immobilized fungus by electrothermal atomic absorption spectrometry

A flow solid phase extraction procedure based on biosorption of Pt(IV) and Pd(II) on Aspergillus sp. immobilized on cellulose resin Cellex-T was proposed for the separation and preconcentration of Pt and Pd before their determination by electrothermal atomic absorption spectrometry (ETAAS). The analytical conditions including sample pH, eluent type, flow rates of sample and eluent solutions were examined. The analytes were selectively retained on the biosorbent in acidic medium (pH 1) and subsequently eluted from the column with 1 mL of thiourea solution (0.25 mol L^− 1 thiourea in 0.3 mol L^− 1 HCl). The reproducibility of the procedure was below 5%. The limit of detection of the method was 0.020 ng mL^− 1 for Pt and 0.012 ng mL^− 1 for Pd. The method validation was performed by analysis of certified reference materials BCR-723 (tunnel dust) and SARM-76 (platinum ore). The developed separation procedure was applied to the determination of Pt and Pd in road dust samples by ETAAS.The applied biosorbent is characterized by high sorption capacity: 0.47 mg g^− 1 for Pt and 1.24 mg g^− 1 for Pd.     

Exthaktiv-Spekthophotometrische Bestimmung Von Rh(III) in Gegenwart Der Platinmetalle,Gold Und Silber Unter Anwendung Von 1-(2-Pyridylazo)-2-Naphthol

Abstract

A spectrophotometric method is described for the determination of 25–150μ;g of rhodium (III) using 1-(2-pyridylazo)-2-naphthol. One milligram of Ir(III) or Ir(IV), 200μ;g Ru(IV), 400μ;g Os(IV), 350μ;g Pt(IV), 5 mg Ag(I), and 100μ;g Au(III) do not interfere. Larger amounts of silver and gold are removed as AgCl and, after reduction with ascorbic acid, Au metal. A modification of the method permits the successive determination of 4–100μ;g of Hh(III) and 50–500μ;g of Pd(II) in a single sample.     

Sorption-spectrophotometric determination of zirconium and chromium(VI) from a single sample on a two-layer support using Arsenazo III and 1,5-diphenylcarbazide

The possibility of the sorption-spectrometric determination of zirconium(IV) and chromium(VI) from a single sample using a two-layer support made of polyacrylonitrile fiber filled with a PANF-KU-2 cation exchanger and PANF-AV-17 anion exchanger is studied. After sorption zirconium is determined with Arsenazo III on PANF-KU-2 and chromium is determined with 1,5-dipehnylcarbazide on PANF-AV-17. The sorption of zirconium and chromium is studied in the dynamic mode from solutions of HCl, HNO₃, and H₂SO₄ and the optimal conditions of the simultaneous sorption of zirconium on PANF-KU-2 and chromium on PANF-AV-17 from 0.25 M HCl is chosen. Diffuse reflection spectra of zirconium and chromium complexes have are on the solid phase and the conditions of zirconium determination are optimized. Calibration curves are linear in the range of zirconium and chromium concentration 0.005–0.025 μg/mL; the detection limits are 0.002 μg/mL. The selectivity of zirconium and chromium determination is tested in the presence of interfering ions. A procedure is developed for their determination from a single sample at zirconium to chromium ratios from 3: 1 to 1: 3.     

Extraction and spectrophotometric determination of platinum(IV) using tetramethylthiuram disulfide

The extraction and photometric determination of platinum(IV) with tetramethylthiuram disulphide has been studied. Addition of an excess of stannous chloride and maintaining acidity to 2–6 M with HCl is necessary for quantitative extraction. With 10 ml of TMTD in toluene and equilibration for 30 sec, platinum is extracted as a pale yellow complex in the organic phase. It has λ_max at 348 nm and obeys Beer's law in the concentration range of 0.2 to 9.0 μg of Pt per ml. The complex is stable for 3 hr. The ratio of Pt:TMTD in the extracted species is found to be 1:1. Most of the anions and cations are tolerated in large ratio. The method can be satisfactorily applied for the determination of platinum in the presence of four- and eightfold excesses of ruthenium and osmium, respectively.