Enhanced Adsorption of Toxic and Biologically Active Levofloxacin Residuals from Wastewater Using Clay Nanotubes as a Novel Fixed Bed: Column Performance and Optimization.

Kaolinite nanotube particles (KNTs) were synthesized by a chemical exfoliation and scrolling process in the existence of sonication waves. The KNT product was identified as a mesoporous material (12 nm in pore diameter) with high surface area (105 m/g) and promising adsorption affinity for the levofloxacin antibiotic (LVOX) residuals in wastewater. The KNT particles were used as a fixed bed in the continuous adsorption column system for LVOX considering the essential variables. The investigation of the KNT fixed bed in a continuous column for 1800 min verified its suitability to reduce the LVOX content in 9 L of polluted solutions by 80.4%. This was recognized after using the KNT bed of 4 cm in height, a flow rate of 5 mL/min, a pH value of 8, a total flow interval of 1800 min, and an LVOX concentration of 10 mg/L. The regeneration study of the bed declared effective recyclability properties for the KNT particles in the LVOX adsorption column system. The dynamic properties of the KNT bed-based column system were explained based on Thomas, Adams-Bohart, and the Yoon-Nelson kinetic models. The LVOX adsorption reaction by KNTs follows Langmuir behavior with homogeneous and monolayer uptake form. The Gaussian energy (2.05 kJ/mol) and the thermodynamic parameters emphasized physical, spontaneous, and exothermic adsorption reactions for LVOX by KNTs.