EXTRACTION CONCENTRATING OF SCANDIUM (III) IN COMPLEX FORM WITH 2-HYDROXY-5-T-BUTYLPHENOL-4-METOXYAZOBENZENE AND ITS DETERMINATION BY ATOMIC-ABSORPTION SPECTROMETRY

Complexation of scandium 2-hydroxy-5-T-butylphenol-4-metoxyazobenzene (HR) was studied by atomic-absorption and spectrophotometric methods. Optimum conditions of formation and extraction of the complex were found. Maximum light absorbance of a complex in n-butanol is in the range of 470÷480 nm. Molar absorption coefficient equals to (2.2–3.0).104. Stability constant of scandium in n-butanol is л=2.8·1010. Selective and sensitive techniques of extraction-atomic absorption determination of scandium in soils were developed

Thermal Conductivity of Sand-Lime Products Modified with Foam Glass Granulate

Waste glass constitutes a significant part of general waste worldwide. Unfortunately, only a small percentage is recycled. It is, therefore, quite important that it can be applied in the production of construction materials. The main aim of this article is to determine the thermal conductivity of the products modified with granulated foam glass (GFG) (recycled product) of the 0.25–0.5 mm fraction, as well as to indicate dependence of the change in volume density of samples caused by the use of GFG and the change of the thermal conductivity coefficient compared to reference samples. For the purpose of this research, various parameters were examined i.a. volume density, water absorption, determination of the pore size distribution by mercury porosimetry and determination of the heat conduction coefficient with the use of a plate apparatus. The test results were developed on the basis of a mathematical model that determined the influence of the filler on the functional properties of the product. The research has shown that the use of GFG in the sand-lime products will contribute to lowering their thermal conductivity by more than 50% compared to traditional products.

Moment analysis in collision-induced absorption: Determination of a single parameter empirical model for the induced dipole moment of He-Ar gas mixtures

We present a method for the construction of a one-adjustable-parameter empirical model for the induced dipole moment. The method is based on classical physics principles and relies on the first three spectral moments of the collision-induced absorption spectra at various temperatures and new interaction potentials. In this work it is applied to the spectra of He-Ar mixtures. Our values are in good agreement with the available ab initio data. The profiles calculated with these models at various temperatures are in excellent agreement with experiment.

Extractive separation of selenium for atomic-absorption determination in purified sulfur

The expanding use of sulfur in medicine, science and technology has tightened the requirements for the impurity composition, including the content of selenium in sulfur. Combined extraction-atomic absorption methods have been developed to determine selenium in purified sulfur. The possibility of using thiourea derivatives such as sodium diethyldithiocarbamate and diphenylthiocarbazone for the extraction of microgram amounts of selenium from sulfuric acid solutions was studied. Optimal conditions for the extraction of selenium from sulfate solutions are determined. Two procedures for selenium separation are proposed: extraction of selenium diethyldithiocarbamate with ethyl acetate from a solution of sulfuric acid with pH 3 or extraction of selenium dithizonate with chloroform from a 5.25 – 6.0 M sulfuric acid solution. The results of the extraction-atomic absorption determination of selenium in sulfur are compared for both procedures of selenium separation. The accuracy of the selenium determination in purified sulfur is confirmed by the method of varying sample weight. The optimal temperature-time parameters for the electrothermal atomic absorption determination of selenium are determined. The limit of selenium determination is 1 × 10–5 % wt. The values of sr in the range of selenium content 2 × 10–5 — 1 × 10–4 % wt. change from 0.10 to 0.12.

New Atomic Absorption Methods for Metals Determination in Aviation and Automotive Gasoline

New methods for direct atomic absorption determination of lead and lithium as antiknock additives components in aviation and automotive gasoline in the concentration ranges 100–1700 (Pb) and 2.5/0.25–100 (Li) mg/L have been developed. To overcome the difference in analytical signals for samples and standard solutions due to concentration values and matrix effects the proper sample dilution and the addition of the blank as pure reagent hydrocarbons mixture in the solutions have been offered. The methods have high precision, are simple and may be recommended for gasoline quality control and identification procedures.