Ionothermal synthesis of a CHA-type aluminophosphate molecular sieve membrane and its formation mechanism

• DOI: 10.1016/j.micromeso.2015.06.005
• Publication Date: 2015-06-14T02:30:41Z
• Authors: Xiaolei Li; Keda Li; Huaijun Ma; Renshun Xu; Shuo Tao; Zhijian Tian
• Keywords: 02 engineering and technology; 0210 nano-technology

Abstract A gas permeable CHA-type aluminophosphate molecular sieve membrane was ionothermally synthesized on a porous δ-alumina substrate through the so-called “substrate surface conversion” method. The synthetic conditions for this specific membrane were optimized. The temperature, time and the amounts of H 3 PO 4 and HF in the initial synthesis solution were investigated. X-ray diffraction (XRD), scanning electron microscopy (SEM) and gas permeation were performed to characterize the entire formation process for the CHA-type molecular sieve membrane. A formation mechanism of the “substrate surface conversion” method was proposed. The transformation of the gel layer to the CHA membrane via a solid transformation mechanism was suggested.