β-Cyclodextrin/carbon dots-grafted cellulose nanocrystals hydrogel for enhanced adsorption and fluorescence detection of levofloxacin

In this study, a novel hydrogel, β-cyclodextrin/carbon dots-grafted cellulose nanofibrils hydrogel (βCCH), was fabricated for removal and fluorescence determination of levofloxacin (LEV). A comprehensive analysis was performed to characterize its physicochemical properties. Batch adsorption experiments were conducted, revealing that βCCH reached a maximum adsorption capacity of 1376.9 mg/g, consistent with both Langmuir and pseudo-second-order models, suggesting that the adsorption process of LEV on βCCH was primarily driven by chemical adsorption. The removal efficiency of βCCH was 99.2 % under the fixed conditions (pH: 6, initial concentration: 20 mg/L, contact time: 300 min, temperature: 25 °C). The removal efficiency of βCCH for LEV still achieved 97.3 % after five adsorption-desorption cycles. By using βCCH as a fluorescent probe for LEV, a fast and sensitive method was established with linear ranges of 1-120 mg/L and 0.2-1.0 μg/L and a limit of detection (LOD) as low as 0.09 μg/L. The viability of βCCH was estimated based on the economic analysis of the synthesis process and the removal of LEV, demonstrating that βCCH was more cost-effective than commercial activated carbon. This study provides a novel approach for preparing a promising antibiotic detection and adsorption material with the advantages of stability, and cost-effectiveness.