Department of Chemical Engineering, Environmental Engineering Program, Yale University, New Haven, Connecticut 06520-8286, USA.
Environ Sci Technol. 2010 May 15;44(10):3812-8. doi: 10.1021/es1002555.
Recent studies show that osmotically driven membrane processes may be a viable technology for desalination, water and wastewater treatment, and power generation. However, the absence of a membrane designed for such processes is a significant obstacle hindering further advancements of this technology. This work presents the development of a high performance thin-film composite membrane for forward osmosis applications. The membrane consists of a selective polyamide active layer formed by interfacial polymerization on top of a polysulfone support layer fabricated by phase separation onto a thin (40 mum) polyester nonwoven fabric. By careful selection of the polysulfone casting solution (i.e., polymer concentration and solvent composition) and tailoring the casting process, we produced a support layer with a mix of finger-like and sponge-like morphologies that give significantly enhanced membrane performance. The structure and performance of the new thin-film composite forward osmosis membrane are compared with those of commercial membranes. Using a 1.5 M NaCl draw solution and a pure water feed, the fabricated membranes produced water fluxes exceeding 18 L m(2-)h(-1), while consistently maintaining observed salt rejection greater than 97%. The high water flux of the fabricated thin-film composite forward osmosis membranes was directly related to the thickness, porosity, tortuosity, and pore structure of the polysulfone support layer. Furthermore, membrane performance did not degrade after prolonged exposure to an ammonium bicarbonate draw solution.
最近的研究表明，渗透压驱动的膜过程可能是一种可行的脱盐、水和废水处理以及发电技术。然而，缺乏专为这些过程设计的膜是阻碍该技术进一步发展的一个重大障碍。这项工作提出了一种用于正向渗透应用的高性能薄膜复合膜的开发。该膜由界面聚合在聚砜支撑层上形成的选择性聚酰胺活性层组成，聚砜支撑层通过相分离到薄（40 微米）聚酯无纺织物上制造而成。通过仔细选择聚砜铸膜液（即聚合物浓度和溶剂组成）和调整铸膜过程，我们生产出了一种具有指状和海绵状形态混合的支撑层，从而显著提高了膜性能。新的薄膜复合正向渗透膜的结构和性能与商业膜进行了比较。使用 1.5 M NaCl 汲取液和纯水进料，所制备的膜产生的水通量超过 18 L m(-2)h(-1)，同时始终保持观察到的盐截留率大于 97%。所制备的薄膜复合正向渗透膜的高水通量与聚砜支撑层的厚度、孔隙率、曲折度和孔结构直接相关。此外，膜性能在长时间暴露于碳酸氢铵汲取液后并未下降。
