Developing polysulfone-based mixed matrix membrane containing hydrazone-linked covalent organic frameworks towards dye wastewater purification

•Hz-TFPTZ-COF was synthesized using a facile room temperature method.•The room-temperature method can facilitate the large-scale synthesis of COFs for water treatment.•The low loading content of Hz-TFPTZ-COF in the polysulfone membranes has increased the mechanical and dye removal properties.•The Hz-TFPTZ-COF@PSf/PVP membrane can effectively remove cationic dyes with a PWP of 94.69 L. m−2. h−1. bar−1. The shortage of water resources and the increased demand for clean water warrant focused investigations on wastewater treatment. In this regard, mixed matrix membranes (MMMs) have been introduced as economic and efficient tools for removing contaminants from wastewater. The current study deals with the synthesis of a hydrazone-linked covalent organic framework (Hz-TFPTZ-COF) and its incorporation into polysulfone (PSf)/ poly N-vinylpyrrolidone (PVP) matrix to obtain Hz-TFPTZ@PSf/PVP MMM containing different concentrations of Hz-TFPTZ-COF (0–1 wt%). The synthesized Hz-TFPTZ-COF and the prepared MMMs were fully characterized using various analytical techniques. The negative surface charge of Hz-TFPTZ-COF made it a good candidate for removing cationic dyes. Moreover, the effect of Hz-TFPTZ-COF loading on the mechanical properties, porosity, pure water permeability (PWP), and dye rejection of the prepared MMMs was investigated. Hz-TFPTZ-COF concentration as low as 1.0 wt% in the MMM formulation yielded a PWP as high as 94.69 L. m−2. h−1. bar−1 and dye rejection of 92% and 88% for Basic Blue 41 and Methyl Violet, respectively. In addition, the tensile strength of the prepared MMMs was increased from 2.26 to 3.43 MPa. Overall, incorporating the Hz-TFPTZ-COF into PSf/PVP polymeric matrix affords a MMM with superior performance in the purification of cationic dye wastewater.