Development of hydrophobic polymethylhydrosiloxane/tetraethylorthosilicate (PMHS/TEOS) hybrid coating on ceramic membrane for desalination via membrane distillation

Surface modification of polypropylene hollow fiber membranes using fluorosilane for CO2 absorption in a gas-liquid membrane contactor

Conventional methods for improving the hydrophobicity of polypropylene (PP) membranes to prevent wetting phenomena require complex pretreatment procedures in order to activate the surface for enabling the reaction with fluorosilane (FS)-based materials. This study successfully prepared PP membrane contactors with enhanced hydrophobicity through a simple single-step dip-coating method using perfluoroether-grafted silanes for CO2 capture. The FS coating layer on the PP membrane surface was confirmed through ATR-FTIR spectroscopy, XPS, FE-SEM, and EDS. Furthermore, the evaluation of the CO2 absorption performance and long-term stability of the FS-coated PP membrane according to the variation of the gas flow rate (50, 100, 200, 400, and 800 mL/min) confirmed the superior chemical stability and durability of our membranes to those of previously reported hydrophobic membranes. The as-prepared FS-coated PP membrane expands the application scope of gas-liquid membrane contactors for CO2 capture from the flue gas of coal-fired power plants.

Preparation of environment-friendly SiO2 aerogel based on waste boron mud and its adsorption behavior for toluene

To mitigate the environmental hazards of boron mud waste accumulation, we prepared environmental-friendly SiO₂ aerogels by extracting them through alkaline leaching treatment and optimized the experimental conditions. The optimum process parameters for alkaline leaching solution NaOH concentration, leaching temperature, solid-to-liquid ratio, and leaching time were 2 mol/L, 95 °C, 1:4, and 3 h, respectively. In this work, cheap and non-toxic hydroxy silicone oil (PDMS-OH) and hydrogen-containing silicone oil (PMHS) were used as surface modifiers instead of toxic and expensive trimethylchlorosilane (TMCS) in the SiO₂ aerogel modification process. The best performance under the optimum conditions was achieved with 60% PDMS-OH-modified SiO₂ aerogel. Organic liquid spills, represented by toluene, pose a great danger to the environment and water bodies. We treated free toluene on the water surface with the aerogel mentioned above and its adsorption capacity was up to 2,655 mg/g. After the adsorption of toluene, the aerogels coalesced into agglomerates for subsequent collection and handling. Furthermore, after five repeated applications, the adsorption capacity remained at 91.43% of the initial application. Overall, this research provided an inexpensive and simple solution for the treatment of organic liquids in wastewater.