Adsorption characteristics and integrated predictive modeling of quinolone antibiotics on urban river sediments

Adsorption of quinolones on urban river sediments was investigated. • Molecular properties control relative adsorption strengths of quinolones. • Organic matter and iron oxide are key sediment controls on adsorption. • Predictive model integrating molecular and sediment factors was established. Quinolone antibiotics have been frequently detected in aquatic environments, where adsorption onto sediments plays a key role in controlling their environmental partitioning. This process is governed jointly by molecular structures and sediment characteristics, yet their coupled effects remain insufficiently quantified. To better understand and predict antibiotic adsorption onto urban river sediments, this study investigated the adsorption behaviors of 10 quinolone antibiotics using 14 sediments collected from urban rivers in Wuhan, China. Saturated adsorption capacities calculated using the Langmuir model ranged from 9.1 to 128.2 μmol g −1 on a selected sediment, spanning over an order of magnitude and reflecting the influence of specific molecular structures. Adsorption extents were revealed to vary with sediment types, emphasizing the role of sediment physicochemical characteristics. Predictive models describing the sediment-water partition coefficient ( K d ) were independently established based on molecular descriptors and sediment characteristics, achieving robust performance (R 2  > 0.80 and > 0.79, respectively). Analysis revealed that dipole interactions, dispersion and induction interactions, and hydrogen bonding associated with molecular structures, together with sediment organic matter and iron oxide contents, exert dominant controls on adsorption processes. Further, by integrating parameters of both molecules and sediments, an integrated predictive model was developed and validated with satisfactory performance (R 2  = 0.712), capturing adsorption behaviors across diverse sediment-compound combinations. These results provide quantitative insights into structure-reactivity relationships of adsorption on natural sediments, and highlight the significance of integrated frameworks for predicting interfacial adsorption processes of organic contaminants. Download: Download high-res image (257KB) Download: Download full-size image