Mathematical Modelling for Fixed-Bed Column and Batch Adsorption Studies of Antibiotic and CO2 Capture Using Soybean Stover Biochar

Biochar is a versatile material increasingly recognized for its efficacy in wastewater treatment and environmental remediation. Herein, phosphoric acid-activated soybean stover biochar (ASSB) was prepared via torrefaction under inert atmospheric conditions and evaluated for its adsorption capabilities towards pharmaceutical Norfloxacin (NFX) alongside its CO2 capture potential. Comprehensive characterization using FT-IR, XRD, SEM, EDX, TGA-DTA, and BET analysis revealed a substantial surface area of 298.82 m(2) g(-1) for ASSB. Batch adsorption studies demonstrated remarkable maximum adsorption capacities of 203.05 mg g(-1) for NFX. Response surface methodology (RSM) facilitated the optimization of operational constraints. Isotherm and kinetic analyses indicated that the adsorption of NFX confirmed the Langmuir model and pseudo-second-order kinetics, respectively, with thermodynamic assessments confirming the spontaneity of the adsorption process. Column studies further validated the efficiency of ASSB in large-scale applications. Clark model was found to be the best fit out of non-linear Thomas, Bohart-Adams, and Wolborska column modelling. Regeneration capacity was checked using a gamma irradiation dose of 6 kGy with 84% removal up to the fifth cycle. This study underscores the multifunctional utility of ASSB in pharmaceutical wastewater treatment and CO2 capture (49.96 cc g(-1) at 273 K), highlighting its promising prospects for sustainable environmental applications.