Abstract
<title>Abstract</title> <p>β-Lactam antibiotics in aquatic environments pose significant environmental and public health risks owing to their persistence and contribution to antimicrobial resistance. However, the influence of pillar chemistry and synthesis strategy on the structure-performance relationship of pillared clays remains insufficiently understood. In the present study, aluminium- and zirconium-pillared bentonite were synthesized using a microwave-sonochemical hybrid approach that was designed to promote controlled hydrolysis, intercalation, and dispersion of metal polycations within the clay framework. The structural modification increased the specific surface area from 53 to 272 m². g⁻¹ and significantly enhanced the adsorption performance toward ampicillin. Equilibrium data were satisfactorily described by the Langmuir isotherm, while adsorption kinetics followed the pseudo-second-order model. The maximum adsorption capacities at 298 K were 73.67 mg. g¹ for AlPC, 59.17 mg. g⁻¹ for ZrPC, and 16.17 mg. g⁻¹ for pristine bentonite. The developed adsorbents were further validated using a representative hospital wastewater matrix obtained from Doon Hospital effluents. Mechanistic analyses suggest that adsorption involves electrostatic interactions, hydrogen bonding, Lewis acid-base interactions, and pore-filling effects within the expanded interlayer structure. The materials retained satisfactory adsorption performance over three adsorption-desorption cycles using NaOH. A preliminary laboratory-scale cost assessment suggests potential economic viability that requires further validation.</p>