Thiothenoyltrifluoroacetone as the Extracting and Colorimetric Reagent for Bismuth

Abstract

Thiothenoyltrifluoracetone (STTA) was used for the simultaneous extraction and direct spectrophotometric determination of bismuth at microgram concentration. About 98.5 μg of bismuth was extracted as the orange-red colored complex with 10 ml of 0.001 M STTA in carbontetrachloride. The extraction was quantitative at pH 6. The system conformed to Beer's Law in the concentration range of 2.5 to 30 μg/ml of bismuth at 460 nm. The method is both sensitive and selective.

The molar absorptivity was 5.6 × 10³ and sensitivity was 0.037 μg/cm². The method is selective as it is possible to accomplish extraction and colorimetrically determination of bismuth in the presence of 1:50 of several ions. Only ions such as cadmium, tin, iron, titanium and nickel interfere seriously. The overall process of extraction and determination takes hardly 30 minutes. The method is reproducible.     

Microdetermination of Trace Cobalt In Water By Direct Polyurethane From Thin-Layer Spectrophotometry

Abstract

Traces of cobalt in water sample are preconcentrated into a white thin-layer of a parallelpiped polyurethane foam, by the sorption of its thiocyanate complex from acidic medium.

The cobalt thiocyanate complex possesses a blue colour in the foam matrix which has a maximum absorption at 625 nm. the absorbance of the Dlue species is mesured directly in the foam matrix at 680 625 and 540 nm. with different media in the measuring cell. the net absorbance at 625 nm is calculated using a multiwavelength program, where the value of the blank is subtracted. Beer's law is obeyed in the concentration range 0.025-2.0 μg per dl with a detection limit of 25 μg per dl for a 100 ml sample volume. the method is specific for cobalt     

The Energy Distribution of Electronic States in a Liquid Metal

Abstract

A method is developed for calculating for a liquid metal the total number of electronic states below an energy E. The method remains valid when the electron-ion pseudopotential is energy dependent. It is based upon an idea of Lloyd (1967), which we have extended and developed into a form suitable for numerical calculation. Calculations for liquid bismuth reveal no sharp structure in the density of states. The bandwidth for five valence electrons per atom is 1.18 Ry, which corresponds to a bandwidth effective mass of 0.63 electron mass, compared with the first order perturbation estimate of 0.87.     

Indirect Determination of Phosphate by X-ray Fluorescence Spectrometry Using Polyurethane Foam

Abstract

An indirect X-ray fluorescence method for phosphate has been established based on the extraction of phosphomolybdate by polyurethane foam. The molybdenum, which is associated in a fixed ratio with phosphorus, is determined directly on foam, by X-ray fluorescence spectrometry.     

Flameless Atomic Absorption Determination of Volatile Hydrides Using Cold Trap Collection

Abstract

The hydrides of arsenic, antimony, bismuth, and selenium are collected in a liquid nitrogen cold trap and then volatilized into either an argon-entrained air-hydrogen flame or into a Perkin-Elmer HGA-2000 Graphite Furnace for atomic absorption measurement. Flameless atomization results in approximately ten-fold lower detection limits. The sensitivities and detection limits in nanograms are, respectively, 1.0 and 0.2 for arsenic, 5.6 and 1 for antimony, 2.0 and 1 for bismuth, and 40 and 10 for selenium.     

Extraction,Separation and Spectrophotometric Determination of Bismuth(III) Using 1(4′-Bromophenyl) 4,4,6-Trimethyl (1H,4H)-Pyrimidine-2-Thiol

Abstract

The operating conditions for the spectrophotometric determination of bismuth(III) with 1-(4′-bromophenyl)-4,4,6-trimethyl-(1H,4H)-pyrimidine-2-thiol (4′bromo PTPT) as a ligand by a liquid-liquid extraction technique are presented. In acidic conditions bismuth(III) forms a yellow complex with the ligand which can be extracted in chloroform with an absorption maxima at 410 nm. The molar absorptivity is 1.5×10⁴ l mole^?1 cm^?1 and Sandell's sensitivity is 14.3 ng cm^?2. The difference in the absorbance between the chloroform blank and bismuth(III) sample increases linearly in the concentration range 2-14 ppm at 0.3 M hydrochloric acid. The proposed method is extremely sensitive, rapid, reproducible and has been satisfactorily applied to the determination of trace amounts of bismuth(III) in synthetic mixtures, alloys and pharmaceutical formulations and also provides binary separation of bismuth(III) from selenium, tellurium, lead, antimony, copper and gold. The overall process of extraction and determination takes about 15 to 20 min.     

The Preparation and Application of Bismuth (III) Ion‐Selective Electrode Based on Nanoparticles of Bismuth Sulfide

Abstract

Nanoparticles of bismuth sulfide were prepared in the organic phase and the optimum synthesis conditions for the nanoparticles were studied in detail. Transmission electron microscope (TEM) results indicated that the size distribution of the nanoparticles was proportional with an average diameter of 46.4 nm. A novel bismuth ion‐selective electrode (ISE) was prepared by dispersing the bismuth sulfide nanoparticles in polyvinylchloride (PVC) membrane. The linear range was 1.00×10^?8～1.00×10^?4 mol L^?1 and the detection limit was 8.10×10^?9 mol L^?1. The response of the electrode was fast with quite reasonable reproducibility and stability. It was used to determine bismuth in three kinds of stomach medicines and the results were in good agreement with the flame atomic absorption spectrometry (FAAS) method.     

Integrated Bismuth Oxide Ultrathin Nanosheets/Carbon Foam Electrode for Highly Selective and Energy-Efficient Electrocatalytic Conversion of CO2 to HCOOH

Electroreduction of CO₂ into formic acid (HCOOH) is of particular interest as a hydrogen carrier and chemical feedstock. However, its conversion is limited by a high overpotential and low stability due to undesirable catalysts and electrode design. Herein, an integrated 3D bismuth oxide ultrathin nanosheets/carbon foam electrode is designed by a sponge effect and N-atom anchor for energy-efficient and selective electrocatalytic conversion of CO₂ to HCOOH for the first time. Benefitting from the unique 3D array foam architecture for highly efficient mass transfer, and optimized exposed active sites, as confirmed by density functional theory calculations, the integrated electrode achieves high electrocatalytic performance, including superior partial current density and faradaic efficiency (up to 94.1 %) at a moderate overpotential as well as a high energy conversion efficiency of 60.3 % and long-term durability.     

The Determination of Trace Elements by Solid State Luminescence

Abstract

Phosphor luminescence, resulting from the incorporation of trace metal ions into a solid state crystal lattice, has been applied to the quantitative determination of lead and bismuth. The relative fluorescence intensity is linear for 15 to 100 ng of bismuth per spot on calcium carbonate. Lead(II), preconcentrated by co-precipitation with calcium oxalate, can be determined at the ng per ml level by measurement of luminescence after ignition of oxalate to oxide; results are reproducible and the calibration curve is linear up to 15 μg of lead per 100 mg of calcium oxalate precipitate.     

Determination of Traces of Mercury (II) and Phenylmercury by Direct Polyurethane foam Thin-Layer Spectrophotometry

Abstract

The determination of mercury and phenylmercury in the ppb concentration range using polyurethane foam (PUF) thin-layer spectrophotometry has been described. Sorption of mercury and phenylmercury into foam parallepiped loaded with diphenylthiocarbazone (dithizone) contributed to considerable improvement in the absorbance value of the colored species, being concentrated about 140 times.

The method allowed the achievement of satisfactory results, the detection limits are 5 and 10 μg per litre for mercury and phenylmercury, respectively, for 100ml sample volume. The average recovery from tap water amounts to 100% for mercury and 96.6% for phenylmercury.     

Anodic Stripping Voltammetry Determination of Pb(II) and Cd(II) at a Bismuth/Poly(aniline) Film Electrode

Abstract

A novel voltammetric method—anodic—using a bismuth/poly(aniline) film electrode has been developed for simultaneous measurement of Pb(II) and Cd(II) at low µg L^?1 concentration levels by stripping voltammetry. The results confirmed that the bismuth/poly(aniline) film electrode offered high‐quality stripping performance compared with the bismuth film electrode. Well‐defined sharp stripping peaks were observed for Pb(II) and Cd(II), along with an extremely low baseline. The detection limits of Pb(II) and Cd(II) are 1.03 µg L^?1 and 1.48 µg L^?1, respectively. The bismuth/poly (aniline) electrode has been applied to the determination of Pb(II) in tap water samples with satisfactory results.     

Back titration with mercuric nitrate in alkaline medium

Summary Small amounts of bismuth in the order of 100 g up to 25 mg were potentiometrically determined by back titration with mercuric nitrate in alkaline media. The method gives highly accurate results and is further successfully applied for analysis of pairs of bismuth together with one of the cations of calcium, copper, cadmium, zinc, manganese, nickel, lead, aluminium and lanthanum.See also Z. analyt. Chem. 161, 401 (1958); 163, 81 (1958).     

The Determination of Bismuth By Hydride Generation and Non-Dispersive Atomic Fluorescence Detection

Abstract

A sensitive determination of bismuth by hydride generation with non-dispersive atomic fluorescence spectrometric detection is proposed. A commercially available electrodeless discharge lamp was used as the light source. Studies on interference effects from foreign elements are reported and the determination of bismuth in copper metal was considered in detail.     

Preparation of cis-1,1,1,4,4,4-hexafluorobut-2-ene by cis-selective semi-hydrogenation of perfluoro-2-butyne

Cis-1,1,1,4,4,4-hexafluorobut-2-ene has a zero ozone depletion potential (ODP), low global warming potential (GWP) and non-flammable properties, so it is believed to be a potential foam expansion agent. For the synthetic process of cis-1,1,1,4,4,4-hexafluorobut-2-ene, the process catalysts are the key factors for its yield and cost. In this paper, the catalysts of palladium attached to porous aluminum fluoride, to active carbon, to Al₂O₃, and the blends of palladium and bismuth to AlF₃ used to prepare cis-1,1,1,4,4,4-hexafluorobut-2-ene by cis-selective semi-hydrogenation of perfluoro-2-butyne were investigated. The performance of above-mentioned catalysts was compared in reaction process. The experimental results indicate that the additive of bismuth to palladium catalyst is useful for improving the activity and selectivity compared to Pd/C and Pd/Al₂O₃. The role of bismuth in the synthetic process is discussed based on the experimental results and theory analysis.     

The Extraction And Recovery Of Polychlorinated Biphenyls (PCB) Using Porous Polyurethane Foam

Abstract

A fast and efficient method has been developed for the extraction and concentration of PCB from water. The method uses porous polyurethane foam as the absorption column for the PCB which is eluted with acetone and hexane for G. C. analysis.     

Bismuth(III) dication trapped on a chlorobismuthate

Abstract

Metal cations observed with tetrachloroaluminate anion provide insights into the structure and stability of reactive cations. Addition of tris(3,5-dimethylpyrazolyl)borate anion (Tp^Me2) to [BiCl₂][AlCl₄] traps a bismuth(III) dication, [Tp^Me2Bi]²⁺, possessing a highly electrophilic bismuth center with short coordinate Bi―N bonds. [Tp^Me2Bi]²⁺ has weak interactions with the chlorides of [Bi₃Cl₁₃]_∞. Strong affinity of [Tp^Me2Bi]²⁺ with the triflate (OTf) observed in [Tp^Me2Bi(OTf)₃]^- demonstrates the high electrophilicity at bismuth.     

Separation and determination of some trivalent metal ions using rhodamine B grafted polyurethane foam

The incorporation of rhodamine B into polyurethane foam matrix was prepared by mixing the rhodamine B with polyol (polyether) prior to the addition of diisocyanate reagent to form the polyurethane foam material. Rhodamine B grafted polyurethane foam (Rod.B-PUF) was found to be very suitable for the separation and preconcentration of trivalent metal ions e.g. bismuth (III), antimony (III) and iron (III) from thiocyanate solutions. Bismuth and antimony were separated from concentrated acid medium (1–6 M H₂SO₄). Iron (III) was separated from pH 1 to 3. The kinetics of sorption of the Bi (III), Sb (III) and Fe (III) onto the Rod.B-PUF was found to be fast, the extraction is accomplished from 5 to 10 min with average values of half-life of sorption (t_1/2) of 2.9 min. The average values of the Gibbs free energy (ΔG) for the sorption of metal ions onto Rod.B-PUF are ?6.6 kJ mol^?1, which reflect the spontaneous nature of sorption process. The sorption mechanism of the metal ion onto Rod.B-PUF was also discussed.     

Automated Determination of Arsenic,Selenium, Antimony,Bismuth and Tin by Atomic Absorption Utilizing Sodium Borohydride Reduction

Abstract

An automated system for the determination of arsenic, selenium, antimony, bismuth and tin is described. These elements and their compounds are reduced with sodium borohydride to the corresponding hydride. Sensitivity of the automated system is comparable and in most cases better than the manual technique. The automated method was found superior to the manual with respect to reproducibility and ease of operation.     

Foam Countercurrent Chromatography Based on Dual Counter-Current System

Abstract

A novel method of performing foam separation is described. The method utilizes a gas-liquid dual countercurrent flow through a helical column subjected to a particular type of synchronous planetary motion. Samples introduced at the middle portion of the column, in either batch or continuous mode, are separated according to the foam affinity. Any material having an affinity to the foam is quickly carried with the foaming stream and eluted through one end of the column whereas other materials are carried with the liquid stream in the opposite direction and eluted out through the other end of the column. Capability of this foam countercurrent chromatographic method is demonstrated on separations of rhodamine B and Evans blue with an anionic surfactant, SDS, as a collector of rhodamine B. Successful preliminary separation of protein samples, BSA and sheep hemoglobin, indicates that the present method may be effectively applied to separation and purification of various biological samples such as enzymes, membrane receptors, etc.     

Supramolecular assemblies of two piperazine metal-organic bismuth(III) derivatives: a new precursor for the preparation of bismuth(III) oxide bromide nano-structures

Two BiBr₃ supramolecular complexes, [Bi(2-bpmp)Br_2.06Cl_0.94] (1) and [Bi(4-H₂bpmp)Br_4.29Cl_0.71]·H₂O (2) {2-bpmp = N,N′-bis(2-pyridylmethyl)piperazine and 4-bpmp = N,N′-bis(4-pyridylmethyl)piperazine}, were prepared by reaction of bismuth(III) chloride and potassium bromide with two nitrogen donor ligands under thermal gradient conditions using the branched tube method. Compounds 1 and 2 were structurally characterized by single-crystal X-ray diffraction. In monomeric 1, bismuth is coordinated by two pyridyl and piperazine nitrogens of 2-bpmp, and by three halides. Compound 2 is also monomeric but is bonded to only one pyridyl nitrogen. In both compounds, extensive hydrogen-bonding interactions lead to supramolecular networks; in 2, the hydrogen bonds are augmented by π–π stacking interactions. Thermal stabilities of both compounds were studied by thermal gravimetric and differential thermal analyses. Thermal decomposition of nanosized 1 and 2 in air produced BiOBr nanoparticles.