Wiesław Apostoluk

Effect of solvent in competitive alkali metal cation transport across bulk liquid membranes by a lipophilic lariat ether carboxylic acid carrier

Abstract Fluxes and selectivities for competitive alkali metal cation transport across bulk liquid membranes by the lipophilic crown ether carboxylic acid carrier sym -(octyl)dibenzo-16-crown-5-oxyacetic acid have been determined in a variety of chlorinated hydrocarbon and aromatic hydrocarbon solvents. The membrane solvents include: dichloromethane, chloroform, carbon tetrachloride, 1,2-dichloroethane, 1,1,1-trichloroethane, o -dichlorobenzene, toluene and p -xylene. The total alkali metal cation and Na + fluxes, as well as the Na + /K + and Na + /Li + transport selectivity ratios, are compared with selected properties of these organic solvents using the Schmidt, Swain, Koppel–Palm and Kamlet–Taft models. The best correlations are obtained for the Na + flux and the Na + /K + transport selectivity.

Solvent extraction of chromium(III) from alkaline media with quaternary ammonium compounds. Part I

For the first time, it has been experimentally demonstrated that hydrophobic quaternary ammonium compounds dissolved in hydrocarbons are able to effectively extract chromium(III) from alkaline aqueous solutions. Experimental investigation has been performed on extraction of chromium(III) with benzyldodecyldimethylammonium bromide (BDDMA-Br), trioctylmethylammonium chloride (TOMA-Cl) and trioctylmethylammonium hydroxide (TOMA-OH). The yield of chromium(III) extraction was studied at various contact times of the aqueous and organic phases, the composition of the phases, and ageing time of the initial aqueous phase. Under optimal conditions, the extraction of chromium(III) goes quickly with Cr(III) removal exceeding 99%.

Anion exchangers with alkyl substituted guanidyl groups ☆: Gold sorption and Cu(II) coordination

Abstract Two methods of introducing guanidyl groups into polymer matrix were investigated in this work: the reaction of cyanamide (alkyl substituted cyanamides) and carbodiimides with amino groups in modified polystyrene. The new anion exchangers (AEG) with alkyl substituted guanidyl groups contain 1.5–2.3 mmol/g of ligands and exhibit high selectivity towards Au(CN) 2 − anions. From the solution containing 2 ppm of gold the sorption is as high as 30 mg/g. Furthermore, AEG reveal high affinity towards tetrachloroaurate anions. The log K in diluted solution is about 5. The values of gold sorption as dicyanoaurate or tetrachloroaurate anions on AEG with alkyl substituted hydrogen atoms in guanidyl groups is two–four times higher than sorption on anion exchangers synthesized previously by exchange of chlorine with guanidine or aminoguanidine. The EPR studies of Cu(II)-loaded AEG were undertaken to correlate the structural properties of the formed complexes with the nature of the ligands, the ligand concentration, water regain of the resins and pH.

New selective resins with guanidyl groups

Abstract Conditions of reaction between nitrile groups of acrylonitrile/vinyl acetate/divinylbenzene (ANNA/DVB) copolymer and aminoguanidine bicarbonate (AGB) leading to N-substituted amides have been optimized. It has been found that the highest concentration of amino groups can be achieved carrying out aminolysis in the presence of a butanol/water mixture as solvent. Resin obtained under such conditions has 2.20 mmol/g of amino groups and 2.40 g/g water regain. Modified resins display a smaller average pore diameter (5.6 nm) than starting ANNA/DVB copolymer (11.2 nm), indicating that the pore surface is covered with amide gel. When water is used as solvent in aminolysis reaction the degree of modification is smaller and the structure of the resulting resin is similar to that of the starting copolymer. Sorption of Cu(111) on obtained resins is high and proportional to amino group concentration, whereas sorption of Au(CN)2 under alkaline conditions in the presence of excess KCN depends on the structure of the acrylic resin but not on amino group content. Resins which have been modified with AGB in the presence of a butanol/water mixture are 9-times (49.3 mg/g of dry resin) more effective in gold cyanide removal than those modified in water. Other polymers such as: methacrylic acid/trimethylolpropane trimethacrylate (TMPMA), glycidyl methacrylate/TMPMA, glycidyl methacrylate/trimethylolpropane triacrylate and vinylbenzylchloride/styrene/divinylbenzene have been investigated as matrices for aminoguanidine ligands. In the case of the latter polymer, containing 2 wt% of crosslinking agent, sorption of gold cyanide is 55.0 mg/g.

An improved estimation of water-organic liquid interfacial tension based on linear solvation energy relationship approach.

An equation based on the linear solvation energy relationship (LSER) was proposed to predict the interfacial tension between organic liquid and water. The equation takes into account five parameters characterizing properties of the organic liquid molecule: excess molar refraction, solute dipolarity/polarizability, effective hydrogen bond acidity, effective hydrogen bond basicity, and the McGowan molar intrinsic volume. The proposed equation provides a better approximation of the interfacial tension than a similar one derived earlier by Freitas et al. (J. Phys. Chem. B 101 (1997, 7488-7493), which is based on seven terms.

Influence of the structure of chelating resins with guanidyl groups on gold sorption

Abstract The chemical composition and structure of copolymers determines modification degree, concentration of ligands, their accessibility and hence capacity and selectivity of chelating resins. In order to investigate all such influences, a new series of copolymers have been obtained: one with increased polarity and hydrophilicity of polymer surface has been synthesized from vinyl benzyl chloride (VBC), methyl methacrylate (MM) and divinylbenzene (DVB) mixture, another one with toluene and hexadecane as inert diluents. As was expected copolymers synthesized in the presence of hexadecane, which is thermodynamically poor for the mixture of monomers, are porous with small pores (less than 1.8 nm radius) and with macropores (radius bigger than 17 nm). After modification with aminoguanidine bicarbonate, resins with the ligand concentration in the range 1–2 mmol/g are more hydrophilic but porosity decreases due to the elasticity of networks. The copolymers and resins obtained in the presence of toluene have a gel expanded structure. The ability of resins to remove dicyanoaurate complexes has been tested under the following conditions: an excess of potassium cyanide, 50 mg/l of dicyanoaurate concentration and ratio of aminoguanidine ligands to gold complexes 7.7:1. Under these conditions the sorption for the concentration of ligands of 1.2 mmol/g was about 23 mg/g and for 2.0 mmol/g it was 30 mg/g. Sorption of gold increases with increased ligand content. Sorption of gold at pH 7 is higher than at pH 9.5 and at 13.5 comparable to that at pH 9.5. Lowering dicyanoaurate concentration to 5 mg/l decreases the sorption of gold, but when the ligand to dicyanoaurate anions ratio is 1.1:1 the sorption reaches 30 mg of gold/g, which corresponds to a distribution coefficient of 6900. However, better sorption at low ligand to dicyanoaurate ratio is accompanied by much lower extraction degree and distribution coefficient.

The Uptake of Gold(I) from Ammonia Leaching Solution by Imidazole Containing Polymeric Resins

Abstract The polymeric resins containing guanylthiourea, 1-methylimidazole, 2-mercapto-1-methylimidazole ligands have been synthesized from vinylbenzyl chloride-divinylbenzene copolymers and used in the removal of Au(I) from ammonium buffer and ammoniacal thiosulphate solutions. The best gold sorption from ammonium buffer that contains 100 g/dm3 NH3 · H2O and 5 g/dm3 (NH4)2SO4, is reached in the case of 1-methylimidazole resin (2) (27.9 mg/g) and all three resins do not have a measurable sorption of copper(II) ammine complexes. The resins display a higher affinity towards gold(I) from ammoniacal thiosulphate solutions than from the ammonium buffer solution. The XPS analysis of gold loaded resins suggests the presence of gold at Au(I) oxidation state, most likely in the form of ionic pair Au(NH3)2 +OH− or neutral complex AuNH3OH and as highly-dispersed metallic gold. The degree of gold desorption is about 50% using 1% potassium cyanide solution in 0.3% hydrogen peroxide solution. Resins retain their capacity towards gold in five consecutive sorption/desorption cycles.

INTERFACIAL TENSION ESTIMATION IN ORGANIC/AQUEOUS SYSTEM

ABSTRACT Linear solvation energy relationships are used to estimate the interfacial tension at solvent/water interfaces for systems containing ‘dry’ and ‘wet’ solvents. The correlation analysis works also in the systems containing Primene 81R and metal salts. The models ?° = a - b, log xS,W - b2 log xW,S and ?° = a - b log (xS,W + xW,S)give good estimation of the interfacial tension. In the systems containing Primene 81R the surface pressure is correlated with solvent parameters according to relation ?°-7 = a + D7r*=c/3

Estimation of properties of dialkylorganophosphorus acidic extractants in two-phase liquid systems

Abstract The distribution, dimerization and dissociation constants of dialkylorganophosphorus acidic extractants XYP(O)OH affecting their behaviour in the two-phase liquid systems involving ‘dry’ solvents have been correlated with the properties of solutes and solvents in accordance with the Kamlet and Taft and Leggett models. It has been demonstrated that dialkyl derivatives of phosphoric, phosphonic and phosphinic acids could be regarded as members of the same family of acidic extractants. As a result, the distribution, dimerization and dissociation constants as well as the products of these constants can be estimated from the appropriate statistically valid correlations involving the molar intrinsic volumes and Kabatchnik constants of considered acids and solvatochromic parameters π *, α and β of ‘dry’ solvents. Both compared models are adequate for the analysis and estimation of equilibrium constants of dialkylorganosphosphorus acids; however, the Leggett model has been found as more convenient than the Kamlet and Taft model.

ESTIMATION OF ALCOHOL ADSORPTION PARAMETERS AT HYDROCARBON/WATER INTERFACES IN SYSTEMS CONTAINING VARIOUS HYDROCARBONS

Abstract The modified Kamlet-Taft model was used to correlate adsorption parameters (adsorption constants in Szyszkowski and Temkin equations,surface excess and molecular area at saturated interfaces and free energy, enthalpy and entropy of adsorption) of aliphatic alcohols at hydrocarbon/water interfaces with solvent parameters, temperature and molar intrinsic volume of alcohols. Statistically valid equations were obtained which can be used to predict the adsorption behavior of alcohols in extraction systems.