Removal of chloride ions from an industrial polyethylenimine flocculant shifting it into an adhesive promoter using the anion exchange resin Amberlite IRA-420

The strongly basic ion exchanger Amberlite IRA-420 has demonstrated that it can be used for chloride removal. The equilibrium isotherms of chloride ions in PEI-HCl at 20 and 40 °C, and NaCl and HCl at 30 °C in aqueous solution on Amberlite IRA-420 have been obtained. The presence of HPEI+ as coion exerts an important influence on the ion exchange equilibrium. This behavior can be explained by the competition between the protonated amine groups of PEI and the quaternary groups of the resin the chloride ions that tends to promote a slightly non-favorable equilibrium. In the same way, the kinetic studies indicated that the chloride ions are slowly removed in presence of polyethylenimine. Finally, the Nernst-Planck homogeneous model allowed obtaining the self-diffusion coefficients for both the chloride and hydroxide ions in the Amberlite IRA-420 and the values are in the same order of magnitude as those reported in the literature.