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.

Tailings are a significant concern due to their potential release of toxic elements into the environment, posing risks to ecosystems and human health. Therefore, understanding their polluting potential is crucial for effective mitigation strategies. This study evaluates the contaminating potential of eight tailing dams in the upper basin of the Puyango River in southern Ecuador. A physicochemical and mineralogical characterization of the tailings was conducted. The contents of As, Cd, Co, Cr, Cu, Mo, Ni, Pb, Sb, Se, V, and Zn were determined using Inductively Coupled Plasma Mass Spectrometry (ICP-MS) and Inductively Coupled Plasma Optical Emission Spectrometry (ICP-OES). The contamination index (IC) and the risk (R_I) to the environment and population were evaluated. As a result, it was found that As, Cu, Pb, Se, and Zn exceeded the maximum permissible limits in all the samples according to Ecuadorian regulations. Six of the eight tailing dams presented very high pollution levels (21.28 < IC < 298.61), indicating a severe contamination risk. As, Sb, and Se were the most significant contributors to the index, with 29%, 31%, and 20% contribution to the overall IC, respectively. However, the risk assessment indicated a low risk (R_I < 5) to both the population and the natural environment, mainly due to the distance between the tailing dams and the potential receptors. While the present risk associated with the studied tailing dams is low, there exists potential for long-term escalation.