Two-dimensional cellulose acetate membrane-supported mesoporous silica nanosheets for efficient nanosize-based molecules separation

Membrane separation technology plays an important role in nanosize-based molecules separation. The two-dimensional mesoporous membranes have attracted considerable attention for nanosize-based molecules separation. In this work, unsupported mesoporous silica nanosheets (MSNS) were prepared by the growth of template at the water/n-hexane interface using surfactant of cetyl trimethyl ammonium bromide (CTAB) micelles as templates. During the preparation process, the surfactant CTAB was removed to obtain pure two-dimensional MSNS through be washed with ethanol, followed by freeze-drying. The two-dimensional MSNS had uniform nano-pores structure, ultra-thin thickness and high surface area. The pore diameter of MSNS could be controlled by changing the concentration of n-hexane (4–10 nm). By depositing 0.50 mg of MSNS on cellulose acetate (CA) membrane, the CA-MSNS membrane could be used to purify nanosize-based molecules (such as proteins). When the CA-MSNS membranes was used to filter cytochrome c (cyt c) solution and ovalbumin (OVA) solution respectively, 93.46% of cyt c and 47.27% of OVA could pass the CA-MSNS membranes. However, after four times of filtration, OVA molecules were almost completely blocked and cyt c with purity of 99% could be obtained. Moreover, 92.23% of OVA molecules could be recycled through the elution from the surface of CA-MSNS membranes. The results indicated that two-dimensional CA-MSNS membranes had great application potential in the purification of nanosize-based molecules.