Preparation of graphene oxide/silica hybrid composite membranes and performance studies in water treatment.

Water shortages have become a major problem facing the world today. Membrane separation technology is commonly used in water treatment applications. The development of new materials for water treatment can reduce the energy required for water treatment, reduce cost, and improve efficiency. The unique structure and properties of graphene and silica make them attractive materials for preparation of nanofiltration membranes for water treatment. We have successfully prepared a graphene oxide/silica (GO/SiO2) hybrid composite materials by in situ hydrolysis, using tetraethyl orthosilicate (TEOS) as a silicon source in an alkaline environment. The chemistry and structure of these materials are characterized by TEM, FTIR, Raman, and XPS of GO and the GO/SiO2 composite. BET porosimetry reveals that the total pore volume of the composite is 2.84 cm3 g−1, the specific surface area is 2897 m2 g−1, and the average pore diameter is 3.97 nm. We prepared GO membranes and GO/SiO2 composite membranes by vacuum suction filtration. The morphology of the membrane was observed by FESEM and AFM. The composite membrane has a larger surface roughness (Rms = 9.39). We also tested the thermal stability by TGA, and hydrophilicity by water contact angle measurements. The water permeance of the composite membrane is up to 229.15 L m−2 h−1 bar−1, and the rejection of the rhodamine B dye molecules is as high as 99%. The GO/SiO2 hybrid composite membrane has good hydrophilicity and thermal stability, high water permeance and rejection, and can be developed as a high-performance material for water treatment. [ABSTRACT FROM AUTHOR]