Electrokinetic Extraction Research Articles

Long chain alkyl and choline substituted xanthates as extractants for cadmium(II)

The complexes of cadmium(II) with the xanthate anions ROCS − 2 (R = C 2H 5, 1-C 4H 9, 1-C 8H 17, 1-C 18H 37 and CH 2CH 2N(CH 3) + 3) have been synthesized. The stoichiometry of the complexes in aqueous solution has been confirmed as 1:2 for cadmium:xanthate by the mole ratio method. The aqueous solubility of the complexes decreases with increasing alkyl chain length of R, but increases in the presence of the cetyltrimethylammonium and dodecylsulphate detergent ions. The choline-substituted xanthate ligand can be used for the electrokinetic extraction of cadmium ions from soils where its efficiency is approximately 10% of that of EDTA. The addition of the ionic detergents cetyltrimethylammonium bromide (CETAB), cetyltrimethylammonium- p-toluenesulphonate (CETATS) or sodium dodecylsulphate (SDS) increases the aqueous solubility of the cadmium xanthates by some 20%.

Electro-kinetic extraction of contaminants from polluted soil

Atomic force microscopy has been used to study structures formed on the surface of highly oriented pyrolytic graphite following the evaporation of n-dodecane (C12H26) and n-pentane (C5H12). Previous work on the evaporation of n-hexadecane (C16H34) revealed the graphite surface to be decorated with two species of isolated features on the terraces and continuous features at the steps. Models were proposed describing the orientations of the molecules within the features which were dependent on the length of the n-alkane molecule. Experiments have now been performed with shorter-chain alkanes, which show that the structural models derived from the hexadecane system also apply to the observed structures composed of dodecane and pentane.