High-performance CrN tight ultrafiltration membranes prepared by in situ gas-solid catalytic reaction

To expand the industrial application of membranes, high-performance CrN tight ultrafiltration membranes (UF) were prepared by in situ gas-solid reaction using Cr2O3 as a nanoprecursor and TiO2 as a nitriding catalyst in ammonia atmosphere. The phase composition and microstructure of CrN UF membranes were characterized by X-ray diffraction and field-emission scanning electron microscopy with energy-dispersive X-ray spectroscopy. The effects of TiO2 and sintering parameters on the crystalline phase and pore size of CrN UF membranes were investigated. The results identified Ti4+ as a key factor influencing the transformation of the Cr2O3 phase into the CrN phase. The as-prepared CrN membranes exhibited enhanced hydrophilicity, no cracks or pinholes, water flux of 121 L.m(-2)h(-1) bar(-1), and a molecular weight cut-off of 1500 Da. The membranes also had retention rates of 100% for methyl blue (50 ppm) and 90% for methylene blue (50 ppm), which almost remained constant under repeated use. (C) 2021 The Authors. Published by Elsevier Ltd.

Automated summary

High-performance CrN tight ultrafiltration membranes were prepared by in situ gas-solid reaction using Cr2O3 as a nanoprecursor and TiO2 as a nitriding catalyst. The membranes exhibited enhanced hydrophilicity, no cracks or pinholes, high water flux, and retention rates for dyes, with Ti4+ identified as a key factor influencing phase transformation and performance stability.