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

Equilibrium ion exchange isotherms of nicotine on an H+-form strong-acid re sin, Amberlite IR-120, have been determined in order to assess the possibil ity of using such a system to recover nicotine from aqueous nicotine extrac ts. The effect of pH on the experimental equilibrium isotherms has been exp lained by taking into account that the nicotine can be removed by two diffe rent mechanisms: a conventional exchange in ionic form and an acid/base rea ction between the neutral amino group of the nicotine and the fixed acid gr oups of the cation exchanger. Theoretical equations for equilibrium isother ms including the different ways in which the nicotine can be adsorbed by th e resin were derived. The proposed model accounts for the influence of pH o n the equilibrium isotherms by means of an empirical equation. The theoreti cal equilibrium isotherms for any constant pH were determined from the theo retical 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 th e breakthrough curves. Theoretical breakthrough and elution curves were cal culated by using the analytical solution for a rectangular isotherm in a si ngle-component system.