Preparation of α-Alumina-Supported Mesoporous Bentonite Membranes for Reverse Osmosis Desalination of Aqueous Solutions

摘要

In this work, mesoporous bentonite clay membranes approximately 2μm thick were prepared on porous α-alumina substrates by a sol-gel method. Nanosized clay particles were obtained from commercial Na-bentonite powders (Wyoming) by a process of sedimentation, washing, and freeze-drying. X-ray diffraction (XRD), scanning electron microscope (SEM), transmission electron microscope (TEM), and nitrogen adsorption-desorptions (BET) were employed for membrane characterizations. The membranes were tested for reverse osmosis (RO) separation of a 0.1M NaCl solutions. Both water permeability and Na+ rejection rate of the supported membranes were comparable to that of the compacted thick membranes reported in the literature. However, due to the drastically reduced membrane thickness, water permeance and flux of the supported membranes were significantly higher than those of the compacted thick membranes.