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Mesoporous molecular sieves such as MCM-41 and SBA-15 have many desirable
properties for applications as separations media. Their high surface area (~ 1000
m2 g-1) and tuneable uniform pore size of 1.8 - 40 nm make them ideal for size
exclusion separations of proteins and other biological molecules of importance in the
food and pharmaceutical industries. However, the stability of MCM-41 in aqueous
solution is limited. Therefore, in this work a hydrophobic coating has been applied to
siliceous MCM-41 using hexamethyldisilazane to reduce degradation of the structure by
hydrolysis and so increase its stability in water. This coating was covalently bound to
the pore and particle surfaces and was stable in the presence of water for at least 12
days. The protein adsorption properties of the coated material compare favourably to
the uncoated material, with up to 100 % more lysozyme adsorbed on the coated material
than untreated MCM-41. The increased capacity and stability of this material make it
promising for protein separation based on both size exclusion and chemical selectivity.
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