Pervaporation is a membrane separation technology primarily used to dehydrate and recover solvents and also to separate organic–organic mixtures.
It has significant advantage over other separation techniques in that it can be used to effectively ‘break’ azeotropes of mixtures without any of the typically associated physical difficulties and negative environmental impacts of techniques such as azeotropic distillation.
One method of improving membrane flux without significantly compromising selectivity is by inclusion of porous particles into the polymer matrix, e.g. zeolites and silica particles. In porous ceramic–polymer membrane hybrids of this type the engineering of the particles, i.e. size, shape, monodispersivity, pore size and surface chemistry, is of significant importance.
Recent work has shown that the incorporation of engineered PSS into polymer pervaporation membranes can be highly beneficial.
Results show that incorporation of spherical discreet, size-monodisperse mesoporous silica particles of 1.8–2μm in diameter and with pore diameters of 1.8 nm, when incorporated into a poly (vinyl alcohol) [PVA] polymer to produce composite pervaporation membranes, resulted in statistically significant increases in both flux and selectivity. Unlike zeolitic systems, PSS can be very controllably engineered to give a wide range of pore sizes and chemistries and may provide new generations of membranes for various pervaporation applications.