Determination of ion-exchange kinetic parameters for the conducting nanocomposite polyaniline zirconium titanium phosphate

• Kinetics studies envisage the mechanism of ion exchange on the surface of nanocomposite PANI-ZTP.
• Exchange process governed by particle controlled diffusion phenomenon which is faster than the film diffusion.
• Self-diffusion co-efficient of Ba2+ is highest because of greater ionic size.
• Activation energy is calculated by using verified and validated Arrhenius equation.
• Negative values of ΔS° indicate the presence of more active exchangeable sites in the proposed nanocomposite.

The kinetics and mechanism for the ion-exchange processes like Mg(II)–H(I), Ca(II)–H(I), Sr(II)–H(I), Ba(II)–H(I), Ni(II)–H(I), Cu(II)–H(I), Mn(II)–H(I) and Zn(II)–H(I) at different temperatures using approximated Nernst–Plank equation under the particle diffusion controlled phenomenon were studied for the polyaniline zirconium titanium phosphate nanocomposite cation-exchanger. Some physical parameters, i.e. fractional attainment of equilibrium U(τ)U(τ), self-diffusion coefficients (D0), energy of activation (Ea) and entropy of activation (ΔS°) have been estimated. These investigations revealed that the equilibrium is attained faster at higher temperature probably due to availability of thermally enlarged matrix of polyaniline zirconium titanium phosphate (PANI-ZTP) nanocomposite cation exchange material. These results are useful for predicting the ion exchange process occurring on the surface of this cation-exchanger.