A kinetic study of ion exchange in tantalum arsenate to understand the theoretical aspects of separations

The parameters effective diffusion coefficients, activation energies, and entropies of activation are reported for the exchange of the ammine-complex cations of cobalt, viz. [Co(NH3)6]3+ and[Co(en)3]3+ (en = enthylenediamine) on chromium ferrocyanide gel in the H form. The values of these constants throw significant light on the possible structural changes in the exchanger framework caused by the introduction of these large size complex cations. Kinetic measurements have been made as the function of particle size of the exchanger, temperature, and solution concentration of the exchanging ions. The slow step governing the rate of exchange is diffusion of ions through the exchanger particles.

Section: Resultsmentioning

confidence: 50%

Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Kinetics of ion exchange of some complex cations on chromium ferrocyanide gel

Saraswat¹,

Srivastava²,

Sharma³

1979

“…Nancollas and Paterson (2) have found particle diffusion to be the slow step which determines the rate of exchange on zirconium phosphate. Similar observations have also been made on some hydrous oxides ( 2 4 ) and tantalum arsenate (5). However, with less concentrated solutions, the rate-determining step for exchange on zirconium phosphate involves both film and particle diffusion (6).…”

Section: Introductionsupporting

confidence: 59%

wA radiochemical study of the kinetics of ion-exchange on zirconium antimonate

Mathew¹,

Tandon²

1977

This paper reports the radiochemical study of the kinetics of ion-exchange of Rb+ and Cs+ with H+ on zirconium antimonate. The slow step which determines the rate of exchange of these ions is diffusion through the particle. Values for the diffusion coefficients, energy of activation, and entropy of activation have been calculated. The data obtained have been compared with those reported for other organic and inorganic exchangers.

“…The observed concentrations of detergents for the particle-diffusion mechanism are considerably less than those reported for the exchange sorption of some simple as well as complex cations on various sorbents (14)(15)(16)(21)(22)(23)(24)(25)(26)(27)(28). It is well known that the rate of uptake and mobility of ions in solution effectively determine the characteristics of the liquid film surrounding the sorbent particle.…”

Section: Fig 2 Plots Of F Vs T Andmentioning

confidence: 66%

Kinetics and mechanism of ion exchange sorption of some detergents on zinc ferrocyanide

Srivastava¹,

Jain²,

Oberoi³

et al. 1982

Studies have been made on the kinetics and mechanism of exchange sorption of detergents on zinc ferrocyanide using a modified limited bath technique. The effects of concentration, particle size of the sorbent material, and temperature on the sorption rate have been investigated. In the case of cationic detergents (cetyl pyridinium bromide and cetyl trimethylammonium bromide), equilibrium is attained in a period of 2–3 h while 12–16 h are required for anionic detergents, viz., sodium dodecyl sulphate and sodium dodecyl benzene sulphonate. The slowest step governing the sorption rate is found to be the diffusion within the exchanger particles at higher concentrations. The effective diffusion coefficients have been evaluated at four different temperatures and found to be comprised of mainly two components. The energy barriers against the diffusion of exchanging ions have been assessed from the Arrhenius equation. Entropies of activation for various sorption systems have also been calculated. The results are discussed in terms of the size and geometry of the detergents, pore-widths in the sorbent material, and the electric potential gradient along the diffusion path. No change in the internal structure of zinc ferrocyanide is inferred due to the sorption of detergent ions.