J. P. Rawat

Synthesis and characterization of zirconium(IV) iodovanadate and its use as electron exchanger

Samples of zirconium(IV) iodovanadate have been synthesized under varying mixing ratios by adding a mixture of aqueous solution of 0.1 M potassium iodate and 0.1 M sodium metavanadate to aqueous solution of 0.1 M zirconium oxychloride at pH 1. The ion exchange capacity of the material for Na(+) ion was found to be 2.20 meqg(-1) of dry exchanger. The material has been characterized on the basis of chemical composition, FTIR and TGA. The chemical stability of the product has been checked in neutral, acidic and basic media. The product has been used as electron exchanger. The oxidation of Fe(II), Sn(II), ascorbic acid and thioglycolic acid was achieved by batch-equilibrium technique successfully. The maximum redox capacity of the exchanger has been found to be 4.20 meqg(-1) of exchanger by column process.

Chromatographic behaviour of 47 metal ions on titanium(IV) arsenate papers

Titanium arsenate papers with As/Ti ratios 0.2-2.2 have been prepared and 47 metal ions chromatographed on these papers in 10(-5)-4M nitric acid. The effect of pH and of the Ti/As ratio on the R(f) values has been studied. A new quantity R(i) (R(i) = R(f) on untreated papers minus R(f) on treated papers) has been defined. The effect of the concentration of the loading reagents on the Ti/As ratio of the ion-exchanger precipitated on the papers has been determined Contrary to Alberti, it is shown that Lederers equation is obeyed by titanium arsenate papers in the sodium form if the activity of Na(+) ions is considered instead of their concentration. It has also been demonstrated that the selectivity sequence for cations on titanium arsenate papers is not the same as that on titanium arsenate columns.

Synthesis, ion-exchange properties and analytical applications of iron(III) antimonate

Abstract Iron(III) antimonate is readily synthesized and shows excellent thermal and chemical stability. Distribution coefficients for 27 ions are presented. The separation possible include Mg—Sr, AI—Ga, Y—La, Mg—Cd—Zn, and Th—Sm.

Kinetic studies on the exchange of bivalent metal ions on amberlite IRC-718: An iminodiacetate resin

Abstract The rate of uptake of alkaline earth metals, copper, and lead have been investigated by a chelating ion exchange resin containing iminodiacetic acid as ligand attached to the copolymer of styrene and divinyl benzene of macroporous matrix structure. It binds alkaline earth metals, Cu, and Pb by the formation of chelate complexes with the carboxylate group of this resin. The experiments discussed in this work have allowed to establish the paramount importance of the presence of this chelating group in obtaining practically useful rates of metal ion uptake. The kinetic parameters like diffusion coefficient (D o), activation energies (ΔE a) and entropy of activation have been evaluated under the conditions favoring a particle diffusion control mechanism and the study followed the three models i.e., Nernst Planck, B t technique and Ash model. K d values in demineralised water (DMW) were found in the order Cu2+ > Pb2+ > Mg2+ > Sr2+ > Ba2+ > Ca2+.

Sorption equilibria of lead(II) on some indian soils — the natural ion exchangers

Abstract Sorption equilibria of lead (II) on two different types of soils have been studied at 30 and 50°C. The sorption data are analyzed in terms of sorption isotherms , the Langmuir equation, distribution coefficient and various thermodynamic parameters. The data of both the soils fit in close agreement with the Langmuir equation and yield ‘H’ type isotherms at both the temperatures. The sorption of lead (II) is higher in Aligarh soil than Haldighati soil and lower at higher temperature in both the soils. The thermodynamic equilibrium constant K o and Δ G o , ΔH o and ΔS o values have been calculated for predicting the nature of sorption.

Thermodynamics of ion-exchange on ferric antimonate

A simple approach to ion-exchange equilibria on ferric antimonate has been applied. The values of selectivity coefficients for Ba2+, Mg2+, Ca2+ and Sr2+ have been measured using equilibrium experiments at constant ionic strength and at different temperatures from 20 to 60°C. The thermodynamic equilibrium constant and values of ΔG°, ΔH° andΔS° are reported.

Synthesis and ion-exchange properties of niobium arsenate

Abstract Eight samples of niobium arsenate with different ratios of niobium to arsenic have been prepared, and their stabilities and compositions have been determined. The results of thermogravimetry and X-ray studies are reported and compared with those for niobium pentoxide. The separations of Mg 2+ from Al 3+ and Mn 2+ , of Ga 3+ from Al 3+ and of Hg 2+ from Cd 2+ are achieved. A plot of p K sp · r 0 vs. K d is a straight line.

Sorption equilibria of cobalt(II) on two types of Indian soils — the natural ion exchangers

Abstract Sorption equilibria of cobalt(II) on two types of soils have been studied at 30°C and 50°C by a batch process. The sorption data are analyzed in terms of sorption isotherms, the Langmuir equation, the distribution coefficient and various thermodynamic parameters. The adsorption data are in close agreement with the Langmuir equation at both temperatures. Sorption of cobalt(II) is higher in Bhopal soil than in Tehri soil and lower at the higher temperature in both soils. The thermodynamic equilibrium constant K0 and the ΔG0, ΔH0 and ΔS0 values have been calculated in order to predict the nature of sorption.

Equilibrium studies for the sorption of Cu2+ on lanthanum diethanolamine — A chelating material

A new chelating material lanthanum diethanolamine (basically an anion exchanger) has been synthesized. It has been characterized using IR, ESCA, TGA and DTA. Equilibrium studies of Cu2+ sorption have been conducted and a mechanism is proposed for this process.

Separation and Recovery of Some Metal Ions Using Pan Sorbed Zinc Silicate as Chelating Ion Exchanger

Abstract A new inorganic ion exchanger zinc silicate has been synthesized. Its properties such as ion exchange capacity, heat effect and stability etc. have been studied. Sorption of PAN over zinc silicate formed a chelate ion exchanger which showed greater selectivity for some metal ions especially for Cu2+, Ni2+, Co2+, Fe3+, Ag+, Ag3+ and Pt4+. Selectivity has been determined on the basis of distribution coefficients of these metal ions. Separations of Pt(IV) from Fe(III), Au(III) from Fe(III), Ag(I) from Cu(II) and Au(III) from Cu(II) have been reported. The recovery of Pt(IV) and Au(III) from dilute solutions has also been studied.