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2 Physicochemical Problems of Mineral Processing

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Extraction properties of tetraheptylresorcin[4]arenes in relation to Cr(III) ions

Konczyk J., Miroshnychenko S., Kozlowski C.

Physicochemical Problems of Mineral Processing

2016

Vol. 52, iss. 2

835--844

Resorcin[4]arene-based ligand bearing four heptyl chains at the lower rim of the molecule was prepared and modified by four tetradietoxyphosphoryl groups in the upper rim. The compounds obtained were characterized by NMR spectroscopy and their extractability toward chromium(III) ions was studied. The influence of process parameters such as the pH of aqueous phase, agitation time and also extractant’s structure and concentration on efficiency of Cr(III) ions solvent extraction is presented. The highest yield of Cr(III) solvent extraction was obtained for two-hour agitation time of 5.010−4 M metal solution of pH 5.0 and 5.010−3 M chloroform solution of the tetradietoxyphosphorylated derivative of heptyl-resorcin[4]arene. Under optimal conditions, competitive solvent extraction of Cr(III), Zn(II), and Cd(II) ions was performed and separation factor values were established as 77.0 and 24.9 for Cr(III)/Cd(II) and Cr(III)/Zn(II) ions pairs, respectively. The stoichiometry of formed metal-ligand complexes 1:1 was found by classical slope analysis method.

Lead(II) removal from aqueous solutions by solvent extraction with tetracarboxylresorcin[4]arene

Konczyk J., Kozlowski C., Walkowiak W.

Physicochemical Problems of Mineral Processing

2013

Vol. 49, iss. 1

213--222

A novel tetracarboxylresorcin[4]arene was synthesized and its selective complexing ability towards Pb(II) ions was examined. The influence of several parameters such as pH of aqueous phase, agitation time, extractant and modifier concentrations on solvent extraction of Pb(II) ions from the aque-ous nitrate phase into chloroform organic phase was studied. The stoichiometry of the formed metal-ligand complexes was established by slope analysis. Pb(II) ions were quantitatively extracted in the form of 2:1 Pb(II)-resorcin[4]arene complex from aqueous solutions of pH 5.5 to the solution of ligand in chloroform. Competitive solvent extraction experiments in the presence of Zn(II) and Cd(II) ions were also carried out and high selectivity of the extractant towards Pb(II) over Zn(II) and Cd(II) was found. The selectivity order was: Pb(II) >> Cd(II) > Zn(II).