Fabrication of MOF derivatives composite membrane via in-situ sulfurization for dye/salt separation

In this study, metal-organic framework (MOF) layer on the surface of tubular ceramic substrate was prepared as the precursor template to construct ZIF-67-derived CoSx composite membrane through in-situ sulfurization strategy. During the sulfurization process, ZIF-67 as a template was reacted with sulfur ions to form CoSx. Due to the structure change of the ZIF-67 crystal, the aperture of the CoSx was enlarged with the thickness of the separation layer decreased. Moreover, the reorganization of the separation layer caused by the in-situ sulfurization eliminated the non-selective defects. Therefore, a CoSx composite membrane can be obtained with high separation performance and good stability for dye/salt separation. The effects of sulfurization and operation conditions on membrane performance were studied. The CoSx composite membrane had outstanding permeance (751.6 LMH/MPa) and excellent rejection (>99.5%) for dye molecules, while the rejection for salt was below 18.7%. The separation performance of the CoSx composite membrane can be maintained over 100 h, which exhibited great potential in dye desalination.