Extraction of zinc with 3-methyl-1-phenyl-4-trifluoroacetyl-pyrazolin-5-one /FAP/ into chloroform has been investigated as a function of pH. The extraction is masked with cyanide and citrate ions. The extracted zinc can be quantitatively stripped into appropriate aqueous solutions. The distribution data of other metal ions show that zinc can be separated from a number of elements. Few possible applications of such separations from analytical and radiochemical point of view have been suggested.
Extraction of mercury with 3-methyl-1-phenyl-4-trifluoroacetyl-pyrazolin-5-one /FAP/ in chloroform has been described. Maximum extraction /97.3%/ and a distribution coefficient /D/ of 36.5 have been achieved at pH 8. Among the anions tested, thiourea, thiosulphate and cyanide mask the extraction of mercury. Solution of O. 2M KCN was found most suitable stripping agent for mercury. Decontamination data show that mercury can be separated from toxic elements arsenic, cadmium, antimony and thallium; and from other metal ions i. e. Ga/III/, In/III/, Ge/IV/, Sn/II/, Fe/II/, Ir/IV/ and Pt/IV/. A few separations of analytical and radiochemical importance have been discussed.
The sorption behavior of Sn(II) onto Haro river sand has been examined with respect to nature of electrolyte, agitation time,
dosage of sorbent and concentration of sorbate. Maximum sorption (95.5%) has been achieved from 0.034M hydrochloric acid solution
after equilibrating sorbate (2·10−5M) and sorbent (50 mg) for 120 minutes at aV/W ratio of 90 cm3·g−1. The kinetic data have been subjected to Morris-Weber and Lagergren equations. The kinetics of sorption proceeds a two stage
process consisting of a relatively slow initial uptake followed by a much rapid increase in the sorption. The rate constant
of intraparticle transport, Kd, comes out to be 8.75·10−8 mol·g−1·min−1/2 and the first order rate constant for sorption is 0.0416 min−1. The sorption data of Sn(II) onto Haro river sand followed Langmuir, Freundlich and Dubinin-Radushkevich (D-R) type isotherms.
The Langmuir constant,Q, related to sorption capacity and,b, related to sorption energy are computed to be 10.6±1.1 μmol·g−1 and 1123±137 dm3·mol−1, respectively. The D-R isotherm yields the values ofCm=348±151 μmol·g−1 and β=−0.01044±0.0008 mol2·kJ−2 and ofE=6.9±0.3 kJ·mol−1. In all three isotherms correlation factor (γ) is ≥0.99. The influence of common anions and cations on the sorption has been
investigated. Zn(II), Mg(II), oxalate, Pb(II), Mn(II) and tartrate reduce the sorption significantly whereas Fe(II) causes
substantial increase in the sorption. It is essential that all ions causing a decrease in the sorption of Sn(II) must be absent
from the sorptive solution otherwise low sorption yields would result.
The sorption of Cd(II) on Haro river sand from deionized water is reported. The sorption system obeyed according to the Freundlich and Dubinin–Radushkevich (D-R) isotherms. The Freundlich parameters 1/n = 0.67±0.05 and of A = 1.38±1.14 mmole·g-1 have been ascertained. D-R isotherm yields the values of = -0.003741±0.000321 kJ2·mole-2, Xm = 0.23±0.21 mole·g-1 and of E = 11.6±0.5 kJ·mole-1. The influence of common anions and cations on the sorption was examined. Trivalent Bi enhances the sorption whereas Fe, Cr, Al and chromate ions reduce the sorption significantly. Hf(IV) and Ag(I) indicate substantial sorption (61–98%) whereas Gd(III), Re(VII) and Sc(III) show low sorption (<5%). The elements having low sorption can be separated from elements indicating higher sorption using Haro river sand column.
The extraction of group VIII elements with 1-phenyl-3-methyl-4-trifluoracetyl-pyrazolone-5 from aqueous solutions in chloroform
has been studied as a function of pH. Fe(III), Ni(II), Pd(II) and Rh(III) show partial extraction whereas Co(II) is extracted
quantitatively. The effect of citrate, cyanide, fluoride, iodide, thiosulphate and thiourea on the extraction of metal ions
has been investigated. Back-extraction studies were carried out to strip metal ions from organic phase into appropriate aqueous
solutions. Based on these findings some useful analytical separations have been proposed and a few of their possible applications
have been discussed.
The extraction of group IB, IIB and IIA-VA elements with 1-phenyl-3-methyl-4-trifluoroacetyl-pyrazolone-5 in chloroform has
been investigated as a function of pH. The stripping of metal ions into solutions of KCN, HClO4 and appropriate pH buffers has been studied. The masking effects of cyanide, citrate, iodide, thiosulphate and thiourea on
the extraction have been examined. Selective group and individual separations have been proposed on the basis of pH control,
masking effects and back-extraction.
The adsorption of cadmium on manganese dioxide has been investigated from different media in relation to shaking time, pH, composition and concentrations of electrolyte, adsorbent and adsorbate. The conditions for maximum adsorption have been established. Serious interference of EDTA in the adsorption is noticed. The selectivity of the oxide for different metal ions has been examined. More than 98% adsorbed cadmium is eluted, with 50 cm3 of 3M nitric acid solution from the oxide column.
The extraction of palladium/II/ with diphenyl-2-pyridylmethane /DPPM/ in benzene has been investigated from thiocyanate-nitrate media and optimized. Thiosulphate ions showed strong interference and reduced the extraction below 1%. Separation factors determined for most of the elements were better than 103. This extraction method affords palladium preconcentration and its separation from Sc/III/, Co/II/, Cu/II/, Zn/II/, Se/IV/, Sr/II/, Ru/III/, Cd/II/, Cs/I/ and Eu/III/. Few possible applications of such separations have been cited.
Sorption of europium on zirconium oxide has been studies as a function of shaking time, concentration and nature of electrolyte. The effect of initial europium concentration and the amount of adsorbent has been investigated in the range from 6.6·10–10 to 6.6·10–8 mol·dm–3 and between 10 to 200 mg of the oxide. Maximum sorption (>99.8%) from pH 10 buffer and low sorption (<3%) was observed from 0.01 mol·dm–3 nitric or perchloric acid solution. Citrate, sulfate, EDTA and carbonate reduced the sorption significantly. Under optimal conditions Ag(I), Cs(I), Tc(VII), Sb(V), Cu(II), Nd(III), Fe(III), and especially Nd and Fe showed low distribution coefficients. The data followed both Dubinin-Radushkevich and Langmuir-type isotherms. The mean free energy, of sorption was evaluated to be 10.1 kJ mol–1 and the sorption capacity was found to be 22.2 mmol g–1, using the Dubinin-Radushkevich isotherm.
Adsorption of mercury onto manganese dioxide was studied in relation to the concentrations of electrolyte, adsorbent and adsorbate and foreign ions. Adsorption of other metal ions under similar conditions was also measured. Adsorption decreases with increasing electrolyte concentration. Thiosulfate, thiocyanate, iodide and all cations tested suppress the adsorption; the greater the ionic potential of cation, the weaker the adsorption of mercury. Adsorption follows the Freundlich-type isotherm over a wide range of mercury concentration (10–7–10–8 g·ml–1). 98% of the adsorbed mercury can be eluted from the oxide column with 60 ml of 3M nitric acid solution.