Recovery of nicotine from aqueous extracts of tobacco wastes by an H+-form strong-acid ion exchanger

Equilibrium ion exchange isotherms of nicotine on an H+-form strong-acid resin, Amberlite IR-120, have been determined in order to assess the possibility of using such a system to recover nicotine from aqueous nicotine extracts. The effect of pH on the experimental equilibrium isotherms has been explained by taking into account that the nicotine can be removed by two different mechanisms: a conventional exchange in ionic form and an acid/base reaction between the neutral amino group of the nicotine and the fixed acid groups of the cation exchanger. Theoretical equations for equilibrium isotherms including the different ways in which the nicotine can be adsorbed by the resin were derived. The proposed model accounts for the influence of pH on the equilibrium isotherms by means of an empirical equation. The theoretical equilibrium isotherms for any constant pH were determined from the theoretical equations. An additional equilibrium isotherm for nicotine-NH3 was also obtained. Adsorption, elution, and regeneration experiments have also been reported. Intraparticle diffusivity of nicotine was determined from the breakthrough curves. Theoretical breakthrough and elution curves were calculated by using the analytical solution for a rectangular isotherm in a single-component system.