Nanofiltration membrane with high flux and oil rejection using graphene oxide/β-cyclodextrin for produced water reuse

A nanofiltration membrane with a high affinity to water and high rejection of salts and hydrocarbons was developed by intercalating a supramolecular compound, graphene oxide with β-cyclodextrin (GO-β-CD), into its layer of separation. The GO-β-CD membranes were synthesized by interfacial polymerization of an aqueous solution of (GO-β-CD)/piperazine with an organic solution of 1, 3, 5-benzenetricarbonyl trichloride on porous substrates of polysulfone (PSf). Fourier transform infrared spectroscopy (FTIR), field-emission scanning electron microscope (SEM), energy dispersive x-ray(EDX), and atomic force microscope (AFM) analyses were applied to confirm the successful incorporation of GO-β-CD into the rejection layer of the synthesized membrane and analyze the morphology, surface characteristics, and structure of the membrane surface. The hydrophilicity and porosity of the GO-β-CD-embedded membranes were greatly enhanced and were confirmed by the contact angle decline and permeability enhancement. The collective results and analyses showed that the permeability, salt rejection and oil separation were significantly enhanced by the addition of GO-β-CD. The prepared membranes were featured with hydrocarbons separation efficiency of about 100%, divalent salt rejection of about 89% and monovalent salt rejection of about 74%. The fluxes of the produced membranes were 80% greater than NF bare membranes. Additionally, the GO-β-CD membranes were stable under a long-trail filtration of 15 h and exhibited excellent mechanical and performance stability. The proposed membranes with excellent stability, high flux, salt rejection and oil rejection are highly promising for practical applications such as water desalination.