J. Starý

Systematic study of the solvent extraction of metal β-diketonates

Abstract The extraction of 30 metals (Be, Mg, Ca. Sr, Ba, Sc, La, Ti, Zr, Th, Cr, Mo, U, Mn, Co, Fe, Ni, Pd, Cu, Ag, Zn, Cd, Hg, Al, Ga, In, Tl, Sn, Pb and Bi) by solutions of acetylacetone, benzoylacetone and dibenzoylmethane in benzene has been studied in relation to the pH values for extraction. The extraction constants and two-phase stability constants of the β-diketonates were calculated; these can be used to determine the optimum conditions for the separation of many metals. The linear relationship between the distribution coefficients of β-diketones and their corresponding β-diketonates has been confirmed.

A systematic study of the solvent extraction of metal cupferrates

Abstract The extraction of the cupferrates of 33 metals (Be, Mg, Ca, Sr, Ba, Al, Ga, In, Tl, Se, Y, La, Ti, Zr, Th, V, Nb. Mo, W, U, Mn. Fe, Co, Ni. Pd, Cu, Ag, Zn, Cd, Hg. Pb, Sb and Bi) with chloroform was studied in relation to pH values. The extraction constants and two-phase stability constants of the cupferrates were calculated; these can be used to determine the optimum conditions for the separation of many metals.

Systematic study of the cumulation of elements on alga

The cumulation of 14 elements on alga Chlorella kessleri and Scenedesmus obliquus has been radiometrically studied at different pH and at different concentrations of element investigated in the absence and in the presence of other elements. The cumulation of individual species can be quantitatively described using the affinity constant, maximum value of the cumulation factor or maximum capacity of algal cells to cumulate the species in question. Data for the cumulation of 42 species of 30 elements are summarized.

Mechanism of the uptake of metal cations by Algal Cell Walls

Nondisintegrated sprayed dried cells of Scenedesmus obliquus have been applied for the study of the cumulation of metal cations. It has been found that algal cell walls behave predominantely as polyfunctional weakly acidic cation exchangers. Equilibrium constants for different exchange reactions have been determined radiometrically which allow to calculate the form of algal cell walls in various experimental conditions. Metal cations present in microconcentrations may be cumulated predominantly by another cell wall ligands in comparison with the cumulation of macroconcentrations of the same cations.

Dithizone extraction of methylmercury, ethylmercury and phenylmercury

Abstract The distribution of methylmercury, ethylmercury and phenylmercury species between aqueous phases and pure carbon tetrachloride or dithizone solutions in carbon tetrachloride has been studied in detail. The stability constants of the chloride complexes and the extraction constants are reported. The influence of 16 masking agents at various pH values has been investigated; the distribution data found experimentally are compared with the calculated results.

The cumulation of alkali earths and alkali metals on alga

Abstract The cumulation of strontium, cesium, rubidium and sodium on alga has been radiometrically investigated at different pH and at different concentrations of elements studied in the absence and in the presence of other salts. It has been found that the cumulation can be quantitatively described using the affinity constants K M. The cumulation decreases in the order (log K M-values are given in brackets): H+ (6.2), Ba2+ (4.8), Sr2+ and Ca2+ (4.6), Mg2+ (4.2), Cs+, Rb+ and NH4 + (2.9), K+ (2.7, Na+ (2.6) and Li+ (2.4).

Stability and distribution constants of thallium(I) dithiocarbamates

Stability and distribution constants of thallium(I) chelates with diethyl-(I), pyrrolidine- (II), piperidine- (III), phenylethyl- (IV) and methylphenylethyldithiocarbamate (V) have been radiometrically determined using ion-exchange and solvent extraction methods. Stability constants of individual chelates do not change considerably, however, the distribution constants of neutral chelates increase in the order II

The accumulation of radium, barium and lead in algae

A mixture of radium-224, lead-212 and barium-133 as well as a mixture of lead-210 and bismuth-210 were used for the investigation of these elements in algae Scenedesmus obliquus in dependence of equilibrium pH in the absence and in the presence of other salts. It has been found that the affinity constant KM decreases in the following order (lg KM values are given in parentheses): Ra2+ (5.1), Ba2+ (4.8), Sr2+ and Ca2+ (4.6), Mg2+ (4.2), Cs+, Rb+ and NH4+ (2.9), K+ (2.7), Na+ (2.6) and Li+ (2.4). The uptake of lead and bismuth is more complicated because of the accumulation of free cations as well as hydroxo complexes.

The cumulation of elements on algal cell walls

Cumulation factors of 44 species of 32 elements, determined mainly using radiometric methods, are summarized. On the basis of experimental results obtained, general conclusions on the influence of specific surface of algal cells, on the charge and the concentration of species studied, on the pH-value and on the concentration of other metal salts and complexing agents are drawn.

Cumulation of anionic species on Algal cells

The cumulation of 13 anionic species on alga Chlorella kessleri has been radiometri‐cally investigated at different pH and concentration of species studied. It has been found that the cumulation of anionic species generally decreases with the increase of equilibrium pH and concentration of species studied.