Novel highly stable Guanazole-incorporated ultrathin loose nanofiltration membrane with superior permeability for water desalination and purification

Ultra-thin loose thin-film composite (TFC) nanofiltration membrane with potential high permeability is an urgent need in water purification. However, its tailor-made structure and morphology remains a challenge. Herein, a novel composite membrane was proposed for the first time by introducing 3,5-diamino-1,2,4 triazole (GAZ) and piperazine with trimesoyl chloride (TMC) into polyamide layer. The physic-chemical properties of the membranes prepared with various GAZ concentrations in the aqueous phase were characterized. GAZ-incorporated membranes had a thinner active layer and larger pore sizes as well as smoother surface morphology with increasing GAZ content. The presence of GAZ made the pure water permeance of the membranes 2.3-folds of the typical TFC membrane without GAZ, up to 30.5 LMH/bar with a comparable Na2SO4 rejection of 93.5%. The membranes fabricated with a higher GAZ fraction exhibited superior removal for the dyes of Rose bengal (>99.6%) and Congo red (>97.5%) with the dye permeance over 23.0 LMH/bar, and higher rejection rates for natural organic matters (>98.5%, >98.0% and >93.0% for sodium alginate, bovine serum albumin and humic acid, respectively). The membranes with stable operation implied their potential applications in water desalination and purification.