Molecular sieve membrane technology
Molecular sieves are used as membrane materials for pervaporation membrane and their regular channels are used to separate different components. NaA type inorganic molecular sieve pervaporation membrane is NaA type molecular sieve particles on the tubular porous ceramic membrane support, through the crystal growth (growth) to form A layer of close packing layer of membrane, pore size is about 4.2 A, dynamics of diameter greater than water molecules (~ 2.9 A) and less than most of the organic molecular diameter, showed good shape-selective selectivity to water molecules; On the other hand, the high aluminum content (Si/Al=1) in the molecular sieve skeleton makes it extremely hydrophilic, making NaA inorganic molecular sieve pervaporation film particularly suitable for organic solvent dehydration.
According to the characteristics of the proposed separation material system, molecular sieve membranes with controllable properties were prepared by pretreating ceramic supports, controlling crystal seed, coating method, composition of membrane synthesis materials and parameters of membrane synthesis.
At 75℃, for 90 wt% ethanol feed, the separation coefficient of the prepared membrane >10000, membrane permeability >3 kg/m2h. The product performance reaches the international advanced level.
NaA molecular sieve membrane SEM