Effects of ultrasound on SAPO-34 molecular sieve synthesis

The effects of ultrasound irradiation on SAPO-34 molecular sieve synthesis are investigated for improving its catalytic performance in MTO (Methanol to olefin). The molecular sieve samples are characterized with XRD, SEM, FT-IR, and DTG techniques. XRD results show that the crystallization rate and the crystallinity of SAPO-34 increase apparently after ultrasound irradiation. SEM results show that the crystal size becomes smaller and the size distribution becomes narrower after ultrasound irradiation. Ultrasonic-wave treatment is effective in improving the thermal stability of SAPO-34 molecular sieve. MTO catalytic reaction shows that the SAPO-34 molecular sieve of smaller crystal size has higher selectivity to ethylene and propylene.