Adsorption/Desorption of Organic Acids onto Different Adsorbents for Their Recovery from Fermentation Broths

Abstract

Activated carbon and a weak base resin were used as adsorbents for organic acids of relevance in green chemistry. Equilibrium adsorption studies in single and binary systems of acetic, propionic and butyric acids were carried out using various solvents (water, ethanol, and n-propanol) and equilibrium isotherm models were tested. The resin had a higher adsorption capacity than the activated carbon (about 35 %). Data on adsorption of binary systems suggested competition between the acids and a chain size dependence. In the studies using organic solvents, the resin showed a higher adsorption capacity than the activated carbons. This work showed the importance of conducting a complete and integrated study of an adsorption process including both adsorption and desorption steps. The use of resin with n-propanol as eluent achieved the best recovery in the simulated purification of propionic acid.