Robust and high performance pressure retarded osmosis hollow fiber membranes for osmotic power generation

Novel fabrication perspectives have been demonstrated to molecularly construct robust hollow fiber membrane supports for high performance thin‐film composite (TFC) pressure retarded osmosis (PRO) membranes. For the first time, we found that the desirable hollow fiber supports should possess high stretch resistance and acceptable ductility. The microstructure strength of the hollow fiber support may have more weights on overall robustness of the TFC PRO membranes than the apparent cross‐section morphology. Effectively manipulating the kinetics of phase inversion during spinning by maneuvering bore fluid chemistry, and polymer solution composition is a promising method to tailor the strength of hollow fiber supports. Prestabilization of the TFC membranes at elevated lumen pressures can significantly improve their PRO performance. The newly developed TFC PRO hollow fiber membranes exhibit a power density as high as 16.5 W/m² and a very low specific reverse salt flux (J_s/J_w) of 0.015 mol/L at a hydraulic pressure of 15 bar using synthetic seawater brine (1.0 M NaCl) as the draw solution. © 2014 American Institute of Chemical Engineers AIChE J, 60: 1107–1119, 2014     

Economic comparison of transverse and longitudinal flow hollow fiber membrane modules for reverse osmosis and ultrafiltration

The presently used hollow fiber membrane modules consist of a bundle of fibers in a cylindrical polymer or metal shell parallel to the shell axis. The feed solution flows either through the lumen or at the outside parallel to the fibers. This paper compares the performance of these modules with a new transverse flow module where the hollow fibers are positioned perpendicularly to the flow direction. For both types of modules the product costs are calculated for desalination by reverse osmosis and Dextran concentration by ultrafiltration. These calculations are based on literature data. The main conclusion is that the application of the tr‘ansverse flow module is only attractive if the permeation resistance is mainly determined by the hydrodynamics (ultrafiltration) and not attractive if the membrane permeability is the main resistance (reverse osmosis).     

界面聚合中空纤维正渗透膜的制备和表征

以聚砜为原料,通过浸没沉淀法制备中空纤维基膜,然后采用界面聚合法制备出中空纤维正渗透膜。考察了制膜参数、基膜结构和FO性能三者之间的关系。结果表明基膜的厚度为影响FO性能的主要因素之一。基膜的厚度越厚,FO过程中渗透效率越低。制得PSF中空纤维正渗透膜的厚度为0.129 mm,断裂拉伸力为2.48 N,FO通量为10.3 L·m^-2·h^-1,逆向盐扩散性能为0.15 g·L^-1。