Calcium-alginate/carbon nanotubes/TiO₂ composite beads for removal of bisphenol A

In this study, composite calcium-alginate/carbon nanotubes/TiO₂ beads were prepared and tested for their potential in the removal of bisphenol A (BPA) from aqueous solutions. The removal traits were inspected using a fixed-bed sorption column. By varying parameters such as bed height (15-20 cm), flow rate (2.0-6.0 mL.min^-1) and inlet BPA concentration (10-30 mg.L^-1) we assessed the removal capacity of these composites. The highest sorption capacity of 5.46 mg.g^-1 was achieved at 10 mg.L^-1 BPA concentration, 2.0 mL.min^-1 flow rate and 20 cm bed height at saturation. Adams-Bohart, Yoon-Nelson and Dose-Response isotherm models were applied to evaluate the performance of the column at different inlet concentrations. The experimental data satisfactorily fit the Dose-Response model with high correlation (r² > 0.97) across the breakthrough curve. Regeneration of the used adsorbent beads were performed by immersion in the desorption solvent followed by light irradiation. It was postulated that inclusion of TiO₂ facilitates the desorbed pollutant degradation from the used adsorbent beads.