Beijing Key Laboratory of Water Resources and Environmental Engineering, China University of Geosciences, Beijing, 100083, People's Republic of China.
State Key Laboratory of Hydraulic Engineering Simulation and Safety, School of Civil Engineering, Tianjin University, Tianjin, 300072, People's Republic of China.
Environ Sci Pollut Res Int. 2017 Aug;24(23):19068-19075. doi: 10.1007/s11356-017-9445-z. Epub 2017 Jun 28.
The pesticide gibberellic acid (GA) is a potential endocrine disruptor and environmental toxin; therefore, research into its environmental fate is warranted. Batch studies were conducted to investigate the sorption and desorption characteristics of GA on aquifer media. The results demonstrated special sorption characteristic of GA on ferrihydrite compared to goethite, hematite, montmorillonite, and kaolinite, where the sorption kinetics of GA on ferrihydrite was fitted well with the pseudo-second-order, Elovich, and intra-particle diffusion models. The sorption kinetics of GA on ferrihydrite indicated an initial high sorption rate followed by a slow reaction process. The initial high GA sorption rate may be related to electrostatic sorption and surface complexation reactions on the outer surfaces and at the macropore entrances of ferrihydrite. While the slow step was controlled by GA diffusion into mesopore of ferrihydrite. Analysis of the desorption hysteresis indicated a high hysteresis index (HI) ranging from 0.68 to 17.32, and a low desorption percentage ranging from 18 to 48%. After sufficient desorption, the calculated maximum residual GA quantity due to surface complexation reactions with the ferrihydrite coordinated unsaturated sites was 9.05 ± 0.12 mg g. The calculated maximum quantity of GA trapped within the mesopore was 16.23 ± 0.91 mg g. Graphical Abstract Schematic overview of GA sorption and desorption on five minerals in groundwater.
农药赤霉素（GA）是一种潜在的内分泌干扰物和环境毒素；因此，有必要研究其环境归宿。进行了批处理研究，以研究 GA 在含水层介质上的吸附和解吸特性。结果表明，与针铁矿、赤铁矿、蒙脱石和高岭土相比，GA 在水铁矿上具有特殊的吸附特性，GA 在水铁矿上的吸附动力学很好地符合伪二级、Elovich 和内扩散模型。GA 在水铁矿上的吸附动力学表明初始吸附速率较高，随后反应过程较慢。GA 在水铁矿上的初始高吸附速率可能与静电吸附和表面络合反应有关，发生在外表面和水铁矿的大孔入口处。而缓慢的步骤则由 GA 扩散到水铁矿的中孔控制。解吸滞后分析表明，滞后指数（HI）范围为 0.68 至 17.32，解吸百分比范围为 18 至 48%。经过充分解吸后，由于与水铁矿配位不饱和位的表面络合反应，计算出的最大残留 GA 量为 9.05 ± 0.12 mg g。计算出的被截留在内孔中的 GA 最大量为 16.23 ± 0.91 mg g。图摘要 地下水五种矿物质上 GA 吸附和解吸的示意图概述。
