Development of highly permeable polyelectrolytes (PEs)/UiO-66 nanofiltration membranes for dye removal

Abstract

With suitable pore size, narrow pore size distribution and charged surface, nanofiltration (NF) membranes show great potential in removing or recovering dyes from effluents of printing and dyeing industries. However, low permeance of commercial nanofiltration membranes hampers their widespread application. Herein, we design a kind of high permeance mixed matrix membranes through layer-by-layer (LbL) self-assembly of polyelectrolytes (PEs). The additional solvent pathways constructed by incorporation of UiO-66, a type of Zr-based metal organic frameworks (MOFs), accelerate the water passing through the membranes; the pure water permeance of UiO-66 incorporated PEs membrane (PEM/UiO-66) achieves at as high as 14.8 L m−2 h−1 bar−1 which is 160% higher than the pristine PEs membrane. Meanwhile, the membrane exhibits 96.3% rejection towards MgSO4 with molecular weight cut off (MWCO) of 464.2 g mol−1. The comprehensive separation performance of the mixed matrix membrane outperforms most of state-of-the-art NF membranes fabricated by LbL self-assembly to the best of our knowledge. Most interestingly, the mixed matrix membrane demonstrates solution flux as high as 102 L m−2 h−1 with 99.9% rejection of Congo Red under optimized operation conditions in 240 h continuous operation. Taken together, the UiO-66 incorporated NF membranes show strong promise in removing and recovery of dyes in industrial scale.