Design of Electrospun Hydrophobically Modified Polyacrylic acid Hydrogel Nanofibers and their Application for Removal of Ciprofloxacin

Abstract The global water scarcity crisis has been exacerbated by the increasing demand for clean water and water pollution caused by the persistent release of pharmaceuticals such as ciprofloxasin, into water systems. The biodegradation and adsorption potential of CIP is crucial for its elimination in wastewater treatment systems. However conventional methods in wastewater treatment plant (WWTP) often struggle to efficiently eliminate of CIP from water due to its chemically stability and nonbiodegradability. Many researchers observed that CIP was not biodegraded even after 48 days in municipal WWTP, therefor no CIP removal occurred. The objective of this study was to investigate adsorption potential of CIP using a designed electrospun nanofiber. Within the scope of this purpose, we prepared electrospun acrylic acid (AAc)-based hydrogels modified with n-hexadecyl acrylate (C16A) for the first time and evaluated their efficacy in removing CIP from water. Our results show that the desired fiber size and surface smoothness can be obtained in the electrospun hydrogel containing 35 mol% of C16A. As a result, the AAc-based hydrogel nanofiber containing 35 mol% C16A exhibited superior adsorption properties. The adsorption efficiency of the hydrogel for CIP removal from aqueous medium was as high as 98% under equilibrium conditions. The adsorption process was found to follow the pseudo-second-order model, which suggests chemisorption as the dominant mechanism. Isothermal analysis showed that the adsorption fit well with the Langmuir model, suggesting single layer adsorption on a uniform surface. These results highlight the potential of AAc-based hydrogels for the sustainable removal of pharmaceuticals from wastewater, addressing a critical need in environmental contaminant management. Graphical Abstract