Graphene Oxide Ultrafiltration Membranes

Pressure-driven ultrafiltration membranes are important in food processing, biopharmaceutical sieving and wastewater purification. Advanced ultrafiltration membranes with good separation performance have been attracted more and more attention by people. In this thesis, we report unique laminar graphene oxide ultrafiltration membranes prepared by mono-atomic and two-dimensional graphene oxide via vacuum filtrating, which are of good mechanical property, chemical inertness and narrow pore-size distribution.The primary contents of this thesis are summarized as follows:(1) Ultrafiltration graphene oxide membranes with a pore size in the range from3to5nm have been fabricated, which exhibit good rejection rate of Evans blue dye molecules (85%) and fast water permeance (71Lm-2h-1bar-1). And we also studied the impacts, including salt concentration, pH and the applied pressure on the separation performance of graphene oxide.(2) We used copper hydroxide nanotrands as sacrificing templates and assembled nanostrands-channelled graphene oxide membranes with a newly formed network of nanochannels with a narrow size distribution (3～5nm). Compared to graphene oxide membranes, the pemeance offers a10-fold enhancement without sacrificing the rejection rate and reaches up to695L m-2h-1bar-1, which is more than100times higher than that of commercial ultrafiltration membranes with similar rejection.(3) Based on the experimental and molecular dynamic simulations results, we explored the response of channels within nanostrands-channelled graphene oxide membranes to the applied pressure and for the first time we demonstrated a viscous flow transporting through graphene oxide’s channel with a pore size in the range from3to5nm.