RSM-CCD optimized Prosopis juliflora activated carbon for the Adsorptive uptake of Ofloxacin and disposal studies

Abstract

This research deals with the preparation of Prosopis juliflora activated carbon (PJAC) via pyrolysis and chemical activation of Prosopis juliflora wood and evaluation of its suitability as an adsorbent for the uptake of ofloxacin (OFX) antibiotic. The morphological and chemical properties of PJAC were analyzed using different characterization techniques, and the effects of experimental parameters related to OFX adsorption were evaluated. Experiments for the OFL adsorption on PJAC were designed by Central composite design (CCD) based on response surface methodology (RSM) design expert software and were performed. The influence of initial OFL concentration ( C o ), PJAC dosage (m), time (t) and pH on % OFL removal and capacity (mg/g) (q e ) were calculated. The 3D response surface graphs were also obtained for both responses, and the polynomial quadric model was fitted with higher coefficient values of R 2 . Equilibrium adsorption kinetic study followed pseudo-second-order for OFX sorption onto PJAC. The isotherms such as Langmuir, Redlich–Peterson (R-P) and Freundlich models were well suited for experimental data under optimized experimental conditions and found to be pH = 6, m = 16.23 g/L and t = 336 min. H-bonding and π − π EDA interactions are the dominating adsorption mechanisms involved in the adsorption of OFL onto the PJAC surface. To ensure the safe disposal of OFX loaded PJAC, a stabilization technique was used. Further, to ensure the encapsulation of OFX, a cytotoxicity test was also performed by checking the leachate potential against strains Bacillus halodurans (strain KG1) and Escherichia coli (strain K12) microbes. • PJAC was synthesized using Prosopis juliflora, a harmful weed by pyrolysis technique. • Adsorption ability of PJAC was examined for removal of OFL antibiotic from its aqueous solution. • π − π EDA interactions and H-bonding are the dominating mechanisms in adsorption of OFL on PJAC. • Stabilization technique used for safe disposal of OFX loaded PJAC was found efficient.