Preparation, characterization and application of ordered mesoporous sulfated zirconia

A series of ordered mesoporous sulfated zirconia (OMSZ) with different calcination temperatures (400–650 °C) have been synthesized by a self-assembly method using zirconium n -propoxide as raw material, P123 (EO 20 PO 70 EO 20 ) as structure-directing agent and ammonium sulfate as sulfonating agent. The transmission electron microscopy results indicated that the OMSZ had the ordered mesoporous structure and the X-ray diffraction analysis further revealed that the OMSZ had hexagonal ordering structure. The N 2 –BET results showed that the OMSZ were mesoporous materials and, when the calcination temperature was 500 °C, the BET surface area could reach 183 m 2 /g. Temperature-programed desorption of NH 3 (NH 3 –TPD) analysis confirmed that the OMSZ possessed a superacid when the calcination temperature was higher than 450 °C. FTIR-pyridine adsorption results indicated that the OMSZ surfaces were mainly the Lewis acid sites. The catalytic activity of OMSZ was observed for transesterification of waste frying oil, and 92% of yield could be obtained after 6 h at 200 °C.