Copper oxide-incorporated pillared clay granular nanocomposite for efficient single and binary, batch and fixed bed column adsorption of levofloxacin and crystal violet

Abstract

This study investigates single and binary removal of levofloxacin (LV) and crystal violet (CV) using granular CuO-silica pillared clay (G-CuO-SPC) in batch and continuous setups. Silica pillared clay (SPC) synthesized by sol–gel with SiO2 agents and cationic surfactants exhibited a 15-fold increase in surface area after column formation. CuO nanoparticles were incorporated into SPC by direct thermal decomposition, and alginate biopolymer facilitated granulation. Characterization techniques (XRD, N2 adsorption–desorption, FTIR, FESEM and EDS-mapping) confirmed uniformly-dispersed monoclinic CuO nanoparticles in G-CuO-SPC. LV adsorption peaked at pH:5–6, while CV adsorption was almost pH-independent. Sips isotherm modeling revealed maximum capacities for LV (705.2–731.1 mg/g) and CV (914.4–992.4 mg/g) at 25-55℃, with capacities decreasing in binary systems. LV and CV adsorption on G-CuO-SPC was spontaneous, exothermic, and occurred via mechanisms, including electrostatic interaction, van der Waals forces, hydrogen-bonding, and n-π interaction. Fixed-bed analysis favored the Yan model, indicating multilayer adsorption without a classical S-shaped profile.