Biosorption of Cefpodoxime Proxetil Using Modified Agricultural Waste: Acid‐Treated Longan Peel and Surface Interactions in Bioremediation

ABSTRACT This study explores the potential of biosorption process towards the bioremediation of third‐generation broad spectrum antibiotic Cefpodoxime proxetil (CP) using agricultural waste. This research focuses on using the fruit peel of Dimocarpus longan as an efficient and eco‐friendly biosorbent. Furthermore, Acidified longan peel (ALP) powder has altered physicochemical properties of the Longan Peel (LP) with enhanced bio adsorption capacity for CP from 43% (8.60 mg/g) to 88% which implies that 17.62 mg/g of the antibiotic adsorbed on the ALP. The conditions at which the acidification was conducted for raw longan peel powder was with 0.5N HCl for overnight on agitation at 120 rpm on shaker. This chemical modification of the Longan peel improved adsorption process with a spike in the percentage of removal of antibiotic from 43% to 88%. This highest adsorption was obtained under the optimized conditions of agitation at 120 rpm, pH 3, concentration of antibiotic (100 mg/L), adsorbent dosage of 4% and with contact time of 5 h. The kinetic studies revealed that the adsorption mechanism follows a pseudo second order kinetics with an R 2 value of 0.89627 implying the process to be chemisorption associated with chemical bonds like π‐π stacking, hydrogen bonding, hydrophobic‐hydrophobic interactions, and electrostatic interactions. Equilibrium studies data shows that the process to closely fit into the Redlich‐Peterson isotherm model with R 2 value of 0.90667 which indicates deviation from standard Langmuir and Freundlich models. The process follows both monolayer adsorption and multilayer adsorption. The Acidified Adsorbed Longan Peel (AALP) and the Acidified Unadsorbed Longan Peel (AULP) were characterized using FTIR, SEM‐EDX, Zeta Potential, BET and XRD to analyze the structural and surface morphological changes before and after adsorption. Studies unrevealing the potential of agricultural biowaste as a promising and sustainable alternative towards circular economy.