King Abdullah University of Science and Technology (KAUST), Water Desalination and Reuse Center (WDRC), Division of Biological & Environmental Science & Engineering (BESE), Thuwal, 23955-6900, Saudi Arabia.
King Abdullah University of Science and Technology (KAUST), Water Desalination and Reuse Center (WDRC), Division of Biological & Environmental Science & Engineering (BESE), Thuwal, 23955-6900, Saudi Arabia; Guangzhou Institute of Advanced Technology, Chinese Academy of Science, Haibin Road #1121, Nansha District, Guangzhou, China.
J Environ Manage. 2019 Oct 15;248:109240. doi: 10.1016/j.jenvman.2019.07.011. Epub 2019 Jul 13.
We systematically investigated the transport mechanisms of organic micropollutants (OMPs) in a fertilizer-drawn forward osmosis (FDFO) membrane process. Four representative OMPs, i.e., atenolol, atrazine, primidone, and caffeine, were chosen for their different molecular weights and structural characteristics. All the FDFO experiments were conducted with the membrane active layer on the feed solution (FS) side using three different fertilizer draw solutions (DS): potassium chloride (KCl), monoammonium phosphate (MAP), and diammonium phosphate (DAP) due to their different properties (i.e., osmotic pressure, diffusivity, viscosity and solution pH). Using KCl as the DS resulted in both the highest water flux and the highest reverse solute flux (RSF), while MAP and DAP resulted in similar water fluxes with varying RSF. The pH of the FS increased with DAP as the DS due to the reverse diffusion of NH ions from the DS toward the FS, while for MAP and DAP DS, the pH of the FS was not impacted. The OMPs transport behavior (OMPs flux) was evaluated and compared with a simulated OMPs flux obtained via the pore-hindrance transport model to identify the effects of the OMPs structural properties. When MAP was used as DS, the OMPs flux was dominantly influenced by the physicochemical properties (i.e., hydrophobicity and surface charge). Those OMPs with positive charge and more hydrophobic, exhibited higher forward OMP fluxes. With DAP as the DS, the more hydrated FO membrane (caused by increased pH) as well as the enhanced RSF hindered OMPs transport through the FO membrane. With KCl as DS, the structural properties of the OMPs were dominant factors in the OMPs flux, however the higher RSF of the KCl draw solute may likely hamper the OMPs transport through the membrane especially those with higher MW (e.g., atenolol). The pore-hindrance model can be instrumental in understanding the effects of the hydrodynamic properties and the surface properties on the OMPs transport behaviors.
我们系统地研究了有机微量污染物（OMPs）在肥料汲取正向渗透（FDFO）膜过程中的传输机制。选择了四种具有不同分子量和结构特征的代表性 OMPs，即阿替洛尔、莠去津、扑米酮和咖啡因，用于不同的分子。所有的 FDFO 实验都是在膜活性层位于进料溶液（FS）侧的情况下进行的，使用了三种不同的肥料汲取溶液（DS）：氯化钾（KCl）、磷酸一铵（MAP）和磷酸二铵（DAP），因为它们具有不同的性质（即渗透压、扩散系数、粘度和溶液 pH 值）。使用 KCl 作为 DS 会导致最高的水通量和最高的反向溶质通量（RSF），而 MAP 和 DAP 会导致具有不同 RSF 的相似水通量。由于 NH 离子从 DS 向 FS 的反向扩散，使用 DAP 作为 DS 会导致 FS 的 pH 值增加，而对于 MAP 和 DAP DS，FS 的 pH 值没有受到影响。评估了 OMPs 的传输行为（OMPs 通量），并与通过孔阻塞传输模型获得的模拟 OMPs 通量进行了比较，以确定 OMPs 结构特性的影响。当使用 MAP 作为 DS 时，OMPs 通量主要受物理化学性质（即疏水性和表面电荷）的影响。那些带正电荷和疏水性更强的 OMPs 表现出更高的正向 OMP 通量。当使用 DAP 作为 DS 时，更水合的 FO 膜（由 pH 值增加引起）以及增强的 RSF 会阻碍 OMPs 通过 FO 膜的传输。当使用 KCl 作为 DS 时，OMPs 的结构特性是 OMPs 通量的主要因素，但是较高渗透压的 KCl 汲取剂可能会阻碍 OMPs 通过膜的传输，尤其是那些分子量较高的 OMPs（例如阿替洛尔）。孔阻塞模型有助于理解水动力性质和表面性质对 OMPs 传输行为的影响。
