Intensified Heterogeneous Growth of High‐Performance CHA Membranes from Hierarchical Zeolite T Seeds

Abstract

A new method for synthesizing high‐performance CHA zeolite membranes from 15 nm hierarchical zeolite T seeds using a small amount of gel is proposed. The growth of CHA membranes from T seeds is confirmed by X‐ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and fast fourier transform (FFT) patterns. Raman spectroscopy, aluminum and silicon mass balance calculation, and thermodynamic stability investigation follow the contribution of OFF dissolution to CHA growth. It is proposed that the facile decomposition of hierarchical T seeds for localized hetero‐growth of CHA membrane is enabled by their hierarchical high surface area mesostructure. In addition, crucial for the CHA growth is the use of a deposited small amount of gel with high precursor concentration. The CHA membrane exhibits the best separation performance among the reported tubular hydrophilic membranes for ethanol dehydration, with a steady‐state water flux of 4.4 and 3.6 kg m−2 h−1 under neutral and pH≈4 conditions, respectively, and a separation factor (S.F.) exceeding 8,000 after 154 h in operation. This work provides new insights into the seeded growth of zeolite membranes, enabling new synthetic pathways with high precursor utilization while ensuring high performance.