Synthesis And Types Of Ultramicro Low-silicon Zeolites

Ultramicro zeolite molecular sieving is a main trend in the development of molecular sieving field at present. Because the crystalline grain size is very tiny, its outer surface area and the atom number of surface increased sharply, surface energy accreted, surface acid amount augmented, exposed ostiole augmented, aperture shortened, pore volume and pore rate improved, showing obvious volume effect, surface effect and quantum size effect lead to its special physical and chemical character. How to synthesize ultramicro low-silicon zeolite sieving which grain size less small even nanometer is layed store by scientists.This study adopts hydrothermal method, using inexpensive industry material such as sodium silicate substitute orthosilicate carbethoxyl and activated SiO2 for silicon source, common chemistry material alkali metal salt, tetrahydro furan, ethanol substitute for expensive organic template agent, screens systematically the effect when adding different blending agents and different adding quantity on conditions of temperature and time of crystallization and mixing speed. It is in proportion as composition of Na2O﹕Al2O3﹕SiO2﹕H2O=3﹕1﹕2﹕185. Through XRD expertizing phase, observing appearance, IR analyzing structure, laser analyzing granularity and measuring the absorption of ammonium and nitrogen in the water, it confirms adding 0.1molNaBr, 5% guide agent which seasons 24h and 2% tetrahydro furan separately under crystallization temperature 85℃, crystallization time 8h, mixing speed gelatigenous speed 3000r/min and nucleation speed 1500r/min, the crystallization granularities of synthesis zeolite are 160nm,280nm and 150～360nm separately by the contrast of the granularity of routine zeolite is 2μm; also its gross absorption comes at 0.26～0.272ml/L from 0.25mg/L of routine zeolite; The five minute absorption gets to 0.2～0.22mg/L from 0.13mg/L of routine zeolite.We adopt orthogonal experiment method to exam the togetherness effect on the crystallization granularity of zeolite by vary blending agent. The result shows adding simultaneously 0.1molNaBr,2% tetrahydro furan and 5% guide agent which seasons 24h under the crystallization temperature 85℃ and time 4h, its crystallization granularity comes at 120nm, crystallization time gets to 4h from 8h, moreover crystallizes completely.