Improving the Adsorption Performance of Eriochrome Black T Using Aluminum Oxide Films as a Nanoadsorbent

Optimizing industrial wastewater treatment systems requires efficient, cost-effective, and easily adaptable technologies. In this context, adsorption emerges as a promising alternative through the use of advanced nanostructured materials that optimize contaminant removal and facilitate their separation from the treated medium. This work evaluates the use of nanoporous anodic aluminum oxide (AAO) as a nanoadsorbent for the removal of Eriochrome Black T (EBT) dye, analyzing the effect of thermal and chemical modifications on its performance. The results demonstrated that calcination and chemical etching with NaOH, applied individually, increased removal efficiency by 10% compared to untreated AAO. Notably, the combined treatment (calcination + alkaline etching) boosted removal efficiency by 38% after 1 h of contact. Furthermore, this synergistic modification extended the viability of the process to alkaline media (up to pH 10) and allowed the material to be reused for four consecutive cycles, maintaining an 85% removal rate. Finally, the kinetic analysis elucidated the influence of the structural and chemical modifications on the adsorption rate, obtaining satisfactory correlations with various theoretical models.