Electrospun PAN/Biochar okara nanofibers for efficient oxytetracycline removal: Process optimization via response...

The environmental risks associated with oxytetracycline (OTC) contamination have raised increasing concern due to its persistence and contribution to antimicrobial resistance. In this study, electrospun polyacrylonitrile/biochar (PAN/Biochar) nanofibers were developed and evaluated as efficient, reusable adsorbents for the removal of OTC from aqueous solutions. The adsorption process was systematically optimized using experimental studies in conjunction with response surface methodology (RSM) based on Box-Behnken Design (BBD). Characterization analyses confirmed the successful incorporation of biochar into the PAN matrix, resulting in enhanced porosity, electrical conductivity, and surface functionality of the nanofibers. Batch adsorption experiments demonstrated a maximum OTC adsorption capacity of 178.12 mgg^-1 under optimized conditions. The spent nanofibers also exhibited notable antibacterial activity against Escherichia coli and Staphylococcus aureus, indicating their dual functionality. Kinetic data were best described by a pseudo-second-order model, while equilibrium data fit the Harkin-Jura isotherm, suggesting multilayer adsorption on a heterogeneous surface. While numerous studies have explored the removal of pharmaceutical contaminants using electrospun nanofibers, this work uniquely integrates biochar derived from sustainable biomass within a polyacrylonitrile (PAN) matrix to create a multifunctional adsorbent with enhanced adsorption capacity and intrinsic antibacterial properties. Unlike conventional adsorbents that often target single functionalities, the PAN/Biochar composite exhibits synergistic effects arising from combined physical adsorption, chemical interactions, and microbial inhibition. Moreover, the application of Response Surface Methodology with Box-Behnken Design (RSM-BBD) enabled precise optimization of process parameters by systematically evaluating interaction effects, thereby surpassing the limitations of one-factor-at-a-time approaches. This comprehensive strategy not only improves oxytetracycline (OTC) removal efficiency but also addresses the emerging challenge of antimicrobial resistance through a dual-action material platform, highlighting its potential for practical water treatment applications.