The Effect of pH on Aniline Removal from Water Using Hydrophobic and Ion-Exchange Membranes

Filian K.; Mendez-Ruiz J.I.; Garces D.; Reveychuk K.; Ma L.; Melendez J.R.; Díaz-Mendoza C.; Cornelissen E.; Valverde-Armas P.E.; Gutierrez L. · Water (Switzerland) (2025) · DOI: 10.3390/w17040547

Resumen

The presence of aniline, a toxic aromatic amine, has been recorded in different industrial wastewaters. This study aims to investigate the transport of charged and neutral aniline species in aqueous solutions through hydrophobic and ion-exchange membranes (IEMs). Hydrophobic polyoctylmethylsiloxane (POMS) and polydimethylsiloxane (PDMS) membranes and cationic (CEMs) and anionic (AEMs) exchange membranes were tested using diffusion cells and electrodialysis (ED). Diffusion experiments showed that neutral aniline removal reached 90% with POMS and 100% with PDMS due to the concentration gradient between feed (pH = 10) and receiving (pH = 3) solutions. For IEMs, neutral aniline exhibited a faster transport than charged species, with neutral-to-charged transport ratios of 6.6:1 for AEMs and 3.2:1 for CEMs, type I. During ED experiments, an external electric potential increased the charged aniline transport, achieving higher initial fluxes (124.7 mmol·m2·h−1 at pH 4) compared to neutral aniline (43.6 and 53.2 mmol·m2·h−1 for AEMs and CEMs, type I). ED also demonstrated that charged aniline can be removed up to 97% using IEMs. These findings demonstrate the effectiveness of hydrophobic and IEMs in removing aniline, providing insights into its transport mechanism, contributing to the optimization of membrane technologies in treating industrial wastewater effluents, and environmental sustainability.

Instituciones: Universidad del Pacífico