Organosilica bis(triethoxysilyl)ethane (BTESE) membranes for gas permeation (GS) and reverse osmosis (RO): The effect of preparation conditions on structure, and the correlation between gas and liquid permeation properties

Novel antibacterial polyurethane and cellulose acetate mixed matrix membrane modified with functionalized TiO2 nanoparticles for water treatment applications

Bacterial contamination is one of the leading causes of water pollution. Antibacterial polyurethane/cellulose acetate membranes modified by functionalized TiO₂ nanoparticles were processed and studied. TiO₂ nanoparticles were prepared and ultraviolet (UV) irradiated to activate their photocatalytic activity against Escherichia coli (E. Coil) and Methicillin-resistant Staphylococcus aureus (MRSA) bacteria. Functionalized TiO₂ nanoparticles were incorporated in flat-sheet mixed matrix membranes (MMMs). These membranes were characterized for their different properties such as morphology, thermal stability, mechanical strength, surface wettability, water retention, salt rejection, water flux, and their antibacterial performance against E. Coil and MRSA was also tested. The activity of nanoparticles against MRSA and E. coli was analyzed using three different concentrations, 0.5 wt%, 1.0 wt% and 1.5 wt% of nanoparticles and 0.5 wt% of TiO₂ nanoparticles showed maximum growth of bacteria. The maximum inhibition was observed in membranes with maximum nanoparticles when compared with other membranes. All these characteristics were strongly affected by increasing the concentration of TiO₂ nanoparticles in the prepared membranes and the duration of their UV exposure. Hence, it was proved from this analysis that these TiO₂ modified membranes exhibit substantial antibacterial properties. The results are supporting the utilization of these materials for water purification purposes.

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%.