Synthesis of SAPO-34 crystals in the presence of crystal growth inhibitors.

Microporous SAPO-34 molecular sieves were synthesized employing polyethylene glycol, polyoxyethylene lauryl ether, and methylene blue as crystal growth inhibitors. The synthesized SAPO-34 crystals displayed BET surface areas up to 700 m2/g, high CO2/CH4 adsorption ratios, and small crystal size in the approximately 0.6-0.9 microm range with narrow particle size distribution. The enhanced CO2/CH4 adsorption capacities were related to the high N/H ratios observed in the phases prepared in the presence of crystal growth inhibitors. The synthesized SAPO-34 crystals may find potential applications to prepare membranes for CO2 purification.