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 (~25 °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 m2�g�1), pore size (3.67 nm), and pore volume (0.45 cm3�g�1). The hybrid ES40�P123 was twice thicker (2 μm) than TEOS�P123� templated membranes (1 μm). Lastly, the hybrid ES40�P123 displayed highest water flux of 6.2 kg�m�2�h�1. Both membranes showed excellent robustness and salt rejections of >99. © 2020 by the authors. Licensee MDPI, Basel, Switzerland.