Recovery of carboxylic acids produced during dark fermentation of food waste by adsorption on Amberlite IRA-67 and activated carbon

Amberlite IRA-67 and activated carbon were tested as promising candidates for carboxylic acid recoveryby adsorption. Dark fermentation was performed without pH control and without addition of externalinoculum at 37°C in batch mode. Lactic, acetic and butyric acids, were obtained, after 7 days of fermen-tation. The maximum acid removal, 74%, from the Amberlite IRA-67 and 63% from activated carbon wasobtained from clarified fermentation broth using 200 gadsorbent/Lbrothat pH 3.3. The pH has significanteffect and pH below the carboxylic acids pKa showed to be beneficial for both the adsorbents. Theun-controlled pH fermentation creates acidic environment, aiding in adsorption by eliminating use ofchemicals for efficient removal. This study proposes simple and easy valorization of waste to valuablechemicals.