School of Water Resources and Environment, and MOE Key Laboratory of Groundwater Circulation and Environmental Evolution, China University of Geosciences (Beijing), 29 Xueyuan Road, Beijing 100083, PR China.
School of Water Resources and Environment, and MOE Key Laboratory of Groundwater Circulation and Environmental Evolution, China University of Geosciences (Beijing), 29 Xueyuan Road, Beijing 100083, PR China.
Chemosphere. 2019 May;222:593-602. doi: 10.1016/j.chemosphere.2019.01.155. Epub 2019 Jan 28.
Nowadays non-steroidal anti-inflammatory drugs (NSAIDs) are often detected in surface water and groundwater. In this study, effects of environmental factors, i.e., solution pH, ionic strength, temperature and surface-bound organic acids, on bonding of three typical NSAIDs (ketoprofen, naproxen and diclofenac) onto goethite were systematically investigated. Column chromatography, batch experiments, attenuated total reflectance-Fourier transform infrared (ATR-FTIR) spectroscopy and surface complexation modeling were used to probe the adsorption mechanisms. Bonding of three NSAIDs onto goethite was totally reversible, ionic strength-dependent and endothermic (adsorption enthalpy 2.86-9.75 kJ/mol). These evidences supported H-bonding mechanism, which was further explained by ATR-FTIR observation and a triple planes model. Surface-bound organic acids (phthalic acid, trimellitic acid and pyromellitic acid) by inner-sphere complexation with goethite were hard to be desorbed. Surface-bound phthalic acid increased the uptake of NSAIDs but surface-bound trimellitic acid and pyromellitic acid reduced their adsorption. The reason is that the adsorbed phthalic acid can result in a more hydrophobic surface while adsorbed trimellitic acid and pyromellitic acid increased the surface negative charge and polarity. Finally, adsorption of NSAIDs onto goethite with/without surface-bound organic acids was well described by a free energy model, in which contributions of interactions (e.g., H-bonding and van der Waals) were evaluated.
如今，非甾体抗炎药（NSAIDs）经常在地表水和地下水中被检出。在这项研究中，系统研究了环境因素（即溶液 pH 值、离子强度、温度和表面结合的有机酸）对三种典型 NSAIDs（酮洛芬、萘普生和双氯芬酸）与针铁矿结合的影响。柱色谱、批量实验、衰减全反射傅里叶变换红外（ATR-FTIR）光谱和表面络合建模用于探究吸附机制。三种 NSAIDs 与针铁矿的结合是完全可逆的、依赖于离子强度的和吸热的（吸附焓 2.86-9.75 kJ/mol）。这些证据支持氢键机制，进一步通过 ATR-FTIR 观察和三平面模型得到了解释。通过内球络合与针铁矿结合的表面结合有机酸（邻苯二甲酸、均苯三甲酸和均苯四甲酸）难以被解吸。表面结合的邻苯二甲酸增加了 NSAIDs 的摄取，但表面结合的均苯三甲酸和均苯四甲酸减少了它们的吸附。原因是吸附的邻苯二甲酸会导致表面更疏水，而吸附的均苯三甲酸和均苯四甲酸增加了表面负电荷和极性。最后，用一个自由能模型很好地描述了 NSAIDs 在有/无表面结合有机酸存在时与针铁矿的吸附，其中评估了相互作用（例如氢键和范德华力）的贡献。
