Separation of Itaconic Acid from Aqueous Solution onto Ion-Exchange Resins

Itaconic acid (IA) is an unsaturated diacid, a promising compound that might replace part of the petrochemical-based monomers, such as acrylic acid, as a building block for polymers. Recent developments in biotechnology allow the efficient production of IA through fermentation processes. However, further enhancements are necessary in the downstream (recovery) of the product. This investigation examined the separation of IA by adsorption from aqueous solutions, using two types of commercial, strongly basic ion-exchange resins: Purolite A-500P and PFA-300. To evaluate the separation process, the following parameters were tested: pH (from 3.03 to 6.33), temperature (from 10 to 50 degrees C), and IA concentration (from 0.41 to 6.50 g center dot L-1). The Freundlich and Langmuir isotherms were shown to be good fits to the experimental data, and the adsorption kinetics for IA was found to follow a pseudo-second-order (PSO) model. After batch tests, continuous adsorption experiments were carried out using a fixed bed column, and a simplified mathematical model was developed and evaluated in order to determine the adsorption parameters. The experimental data obtained from the column tests were aligned with those obtained from the isotherms and batch simulations with PSO. The resin PFA-300 proved to be more efficient for IA recovery through adsorption, with a maximum capacity of 0.154 g(IA center dot)g(resin)(-1) when compared to the resin A-500P, with a maximum capacity of 0.097 g(IA center dot)g(resin)(-1). Both resins have high affinity for the solute, being half-saturated with equilibrium concentrations below 0.25 g center dot L(-)1 of acid.