Membrane filtration plays an important role in water and wastewater treatments, organic pollutants recovery, textile processing, and pharmaceutical purification. In order to meet the requirement of advanced separations, the development of stimuli-responsive smart membranes is attracting great attention from both academia and industry. In this study, graphene oxide (GO) nanosheets were alternatively assembled with polyethylenimine (PEI) to construct graphene based membrane (GCM). Owing to the presence of carboxylic groups of GO and amine groups of PEI, the interlayer spacing of the assembled GCM could be simply controlled by pH adjustment of feed solution. The results indicated that GCM showed higher flux during the filtration of solution at low pH; by contrast, lower flux was presented in the filtration of high pH solution using GCM. More importantly, the flux shifting phenomena was reversible. It is possible that the protonation-deprotonation of the carboxyl groups on GO nanosheets and amino groups of PEI under different pH conditions caused the shifting of interlayer spacing during the filtration process. Furthermore, the selected molecules with known sizes were used to evaluate the retention ability of GCMs, which indicated a wide adjustable range of interlayer channel. Therefore, it is possible to separate a few components with different sizes in steps, using only one GCM membrane, simply by adjusting pH of the feed solution, which is of great interest for high performance and controllable molecular sieving.<br/>

pH responsive graphene based membrane for controllable molecular sieving

256th National Meeting (2018)

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