Synthesis of SSZ-13 zeolites using calcined rice husk as silica source for propylene production from ethylene and carbon dioxide adsorption

Abstract

A zeolite named SSZ-13, with a small pore of 8-membered rings, is an attractive porous material for DeNOx, CO2 capture/separation, methanol-to-olefin conversion, and direct conversion of ethylene to propylene (DCEP). Although the synthesis of SSZ-13 has been done for a long time and is useful for some applications, further development in the synthesis is required to reduce the production cost or to optimize the preparation. On the other hand, the utilization of waste is important for our sustainability. In this study, SSZ-13 zeolite was synthesized using rice husk-derived silica, for the first time, in order to prepare SSZ-13 at a low cost and utilize agricultural byproducts in zeolite synthesis. Via this research, it was found that SSZ-13s could be synthesized readily by using rice husk-derived silica even without seed crystals. Synthesis at 180 °C for 5–7 d leads to SSZ-13 from the gel with a wide range of silica/alumina ratios. Prepared SSZ-13 in proton form, together with a commercial SSZ-13, was utilized in DCEP and CO2 adsorption at low pressure. The two H-SSZ-13s showed very similar performances in DCEP and CO2 capture, showing an agricultural waste or byproduct, rice husk, can be successfully utilized in the preparation of SSZ-13 zeolites.