Development of Hybrid and Templated Silica-P123 Membranes for Brackish Water Desalination

Water scarcity is still a pressing issue in many regions. The application of membrane technology through water desalination to convert brackish to potable water is a promising technology to solve this issue. This study compared the performance of templated TEOS-P123 and ES40-P123 hybrid membranes for brackish water desalination. The membranes were prepared by the sol-gel method by employing tetraethyl orthosilicate (TEOS) for the carbon-templated silica (soft template) and ethyl silicate (ES40) for the hybrid organo-silica. Both sols were templated by adding 35 wt.% of pluronic triblock copolymer (P123) as the carbon source. The silica-templated sols were dip-coated onto alumina support (four layers) and were calcined by using the RTP (rapid thermal processing) method. The prepared membranes were tested using pervaporation set up at room temperature (similar to 25 degrees C) using brackish water (0.3 and 1 wt.%) as the feed. It was found that the hybrid membrane exhibited the highest specific surface area (6.72 m(2)center dot g(-1)), pore size (3.67 nm), and pore volume (0.45 cm(3)center dot g(-1)). The hybrid ES40-P123 was twice thicker (2 mu m) than TEOS-P123-templated membranes (1 mu m). Lastly, the hybrid ES40-P123 displayed highest water flux of 6.2 kg center dot m(-2)center dot h(-1). Both membranes showed excellent robustness and salt rejections of >99%.