10.1021/je500523n.s001 Md. Dilwar Alam Khan Md. Dilwar Alam Khan Arshia Akhtar Arshia Akhtar Syed Ashfaq Nabi Syed Ashfaq Nabi Kinetics and Thermodynamics of Alkaline Earth and Heavy Metal Ion Exchange under Particle Diffusion Controlled Phenomenon Using Polyaniline-Sn(IV)iodophosphate Nanocomposite American Chemical Society 2014 0.03 M solution activation Heavy Metal Ion Exchange ion exchange ion exchange process metal ion exchange particle diffusion Particle Diffusion Controlled Phenomenon 2014-08-14 00:00:00 Journal contribution https://acs.figshare.com/articles/journal_contribution/Kinetics_and_Thermodynamics_of_Alkaline_Earth_and_Heavy_Metal_Ion_Exchange_under_Particle_Diffusion_Controlled_Phenomenon_Using_Polyaniline_Sn_IV_iodophosphate_Nanocomposite/2264557 The poly­aniline-Sn­(IV)­iodo­phosphate nanocomposite (PANI-SnIP) has been synthesized, and its various kinetic and thermo­dynamic parameters for alkaline earth and heavy metal ion exchange were evaluated. Above 0.03 M solution of metal ions, the particle diffusion controlled phenomenon is found to be predominant (<i>R</i><sup>2</sup> > 0.98). The kinetic and thermo­dynamic parameters like diffusion coefficient (<i>D</i><sub>o</sub>), energy of activation (<i>E</i><sub>a</sub>), enthalpy of activation (Δ<i>H</i>*), entropy of activation (Δ<i>S</i>*), and free energy of activation (Δ<i>G</i>*) were evaluated under particle diffusion controlled phenomenon. The fractional attainment of equilibrium was faster at an elevated temperature, and the rate of exchange is predominated by Hg­(II) ions in the case of multi­component systems. The positive values of the standard enthalpy change (Δ<i>H</i>*) indicate the endothermic nature of the ion exchange process. The ion exchange follows an associative mechanism as indicated by Δ<i>S</i>* < −130 J mol<sup>–1</sup> K<sup>–1</sup>. The comparatively fast kinetics of ion exchange by the nanocomposite depicts its applicability for environmental remediation.