High-performance polyamide thin-film composite nanofiltration membrane: Role of thermal treatment

•A high-performance NF membranes were fabricated by thermal treatment.•The optimal formula is 2 wt.% piperazine, 0.1 wt.% NaOH and 0.25 wt/v% trimesoyl chloride.•95% salt rejection was achieved using the novel NF membrane.•Thermal treatment increased the crosslinking degree of NF membrane.•The optimal membrane water permeability is 13.6 L m−2 h−1 bar−1.