Tannic acid modified MoS2 nanosheet membranes with superior water flux and ion/dye rejection

Abstract

Energy-efficient membranes are urgently needed for water desalination and separation due to ever-increasing demand for fresh water. However, it is extremely challenging to increase membrane water flux and simultaneously achieve high rejection rates of cations or organic dyes. Herein, we report a tannic acid (TA) assisted exfoliation method to fabricate TA-modified MoS2 (TAMoS2) nanosheets with high production yield (90 ± 5%). The TAMoS2 nanosheets membranes show excellent non-swelling stability in water. It is found that a hybrid membrane with 1 wt% of TAMoS2 in MoS2 nanosheets demonstrates overall better performance than pure MoS2 and TAMoS2 membrane. Such a hybrid membrane with a thickness of 5 µm shows fast water flux at around 32 L m−2 h−1 (LMH) and >97% rejection of various cations under static diffusion mode. Under vacuum-driven filtration condition, the as-prepared hybrid membrane demonstrates ultrafast water flux of 15,000 ± 100 L/(m2 h bar) and 99.87 ± 0.1% rejection of multiple model organic dyes. To the best of our knowledge, the above performances are superior to those of all MoS2-based membranes reported previously in terms of water flux and ion/dye rejection. This work represents a leap forward towards the practical applications of 2D TAMoS2 membranes in various engineering and environmental areas.