title: Roles of functional groups of naproxen in its sorption to kaolinite.
abstract: The sorption of acidic anti-inflammatory drugs to soils is important for evaluating their fate and transformations in the water-soil environment. However, roles of functional groups of ionisable drugs onto mineral surfaces have not been sufficiently studied. In this study, batch experiments of naproxen (NPX, anti-inflammatory drug) and two kinds of competitors to kaolinite were studied. The Kd of naproxen to kaolinite is 1.30-1.62 L kg(-1). The n-π electron donor-acceptor (n-π EDA) interaction between diaromatic ring of naproxen (π-electron acceptors) and the siloxane oxygens (n-donors) of kaolinite is the dominant sorption mechanism. The carboxyl group of naproxen can contribute to the overall sorption. A conception model was put forward to elucidate to sorption mechanisms, in which the contribution of n-π EDA and hydrogen bond to overall sorption was quantified. These sorption mechanisms can be helpful for estimating the fate and mobility of acid pharmaceuticals in soil-water environment.
authors.affiliation: School of Water Resources and Environment, Beijing Key Laboratory of Water Resources and Environment Engineering, China University of Geosciences (Beijing), 29 Xueyuan Road, Beijing 100083, PR China. Electronic address: batmanchenglongyu@163.com.
authors.forename: Chenglong
authors.initials: C
authors.lastname: Yu
authors.affiliation: School of Water Resources and Environment, Beijing Key Laboratory of Water Resources and Environment Engineering, China University of Geosciences (Beijing), 29 Xueyuan Road, Beijing 100083, PR China. Electronic address: bi@cugb.edu.cn.
authors.forename: Erping
authors.initials: E
authors.lastname: Bi
mesh_terms: D000327:Adsorption; D000894:Anti-Inflammatory Agents, Non-Steroidal / Q000737:chemistry*; D007616:Kaolin / Q000737:chemistry*; D008956:Models, Chemical; D009288:Naproxen / Q000737:chemistry*; D012833:Siloxanes / Q000737:chemistry; D012987:Soil / Q000737:chemistry*; D012989:Soil Pollutants / Q000737:chemistry*; D013499:Surface Properties
chemical_list: D000894:Anti-Inflammatory Agents, Non-Steroidal; D012833:Siloxanes; D012987:Soil; D012989:Soil Pollutants; D007616:Kaolin; D009288:Naproxen
keywords: Electron donor–acceptor; Kaolinite; Naproxen; Siloxane; Sorption