Carboxylic acids selective recovery from wastewater using electrodialysis
M. Richa, Raúl García-Cervilla, Justo Lobato, P. Cañizares, Manuel A. Rodrigo
Abstract
Carboxylic acids (CAs), such as oxalic acid and acetic acid, are valuable by-products formed during the partial oxidation of organic matter in wastewater treatment. Conventional advanced oxidation processes focus on mineralization, often at high costs, without recovering these useful compounds. This study aims to explore electrodialysis (ED) as a sustainable alternative to separate and purify these acids, adding value to wastewater treatment processes. To do this, in this work, the influence of current density on the efficient purification of oxalic acid from a mixture of four carboxylic acids was studied. Experiments were conducted using a four-compartment electrodialysis cell equipped with the appropriate anion and cation exchange membranes. Key parameters were validated by examining the migration and recovery rates of acids under controlled experimental conditions. A current density of 25 mA/cm² was found to be the most effective for the purification of oxalic acid, achieving higher recovery than other higher and lower current densities. With these results, this study highlights electrodialysis as a viable approach for the selective separation and purification of carboxylic acids. Careful optimization of operational parameters enables efficient acid recovery, enhancing the economic and environmental sustainability of wastewater treatment systems.