Orange peel-derived pectin/cellulose nanofibril hydrogel reinforced by Eu-MOF for simultaneous adsorption and detection of levofloxacin

Orange peel is an abundant polysaccharide-rich agro-industrial residue that is often discarded, causing resource loss and environmental burden. Here, we valorize orange peel-derived pectin into a mechanically robust and photostable fluorescent hydrogel (EuCPH) by embedding uniformly dispersed Europium-based metal-organic framework decorated cellulose nanofibril (Eu-MOF@CNF). The resulting red-emissive EuCPH enables simultaneous levofloxacin (LEV) capture and fluorescence sensing. EuCPH-4 exhibits an ultrahigh Langmuir capacity of 1388.6 mg g −1 and a low limit of detection (LOD) of 0.12 μg L −1 . Adsorption follows the Langmuir isotherm and pseudo-second-order kinetics, consistent with chemisorption-dominated uptake. EuCPH-4 retains 83.8% of its capacity after five cycles with negligible Eu leaching (<8 ppb) and sustains stable performance over ten fixed-bed regeneration cycles. With low-cost orange peel-derived pectin and wood-derived CNF, EuCPH can be produced at ~0.02 CNY g −1 , providing a scalable and economically viable hydrogel platform for antibiotic monitoring and remediation.