Ultrathin, graphene-based membranes for water treatment and methods of their formation and use

A method of forming a membrane, the method comprising:

• dispersing single-layered graphene oxide powder in deionized water to form a single-layered graphene oxide dispersion;
• sonicating the dispersion;
• centrifuging the dispersion to remove large particles and aggregates from the dispersion;
• thereafter, filtering the dispersion through a porous support such that a graphene oxide membrane of layered graphene oxide nanoflakes is formed on the support, the graphene oxide membrane having a thickness of about 2 nm to about 5 nm;
• thereafter, reducing the graphene oxide membrane to form a reduced graphene oxide membrane wherein reducing the graphene oxide membrane comprises heating the graphene oxide membrane to a reducing temperature of about 200° C. to about 250° C. in a vacuum of about 1 torr to about 5 torr, or comprises heating the graphene oxide membrane to a reducing temperature of about 150° C. to about 240° C. in the presence of hydrogen, or comprises exposure of the graphene oxide membrane to hydrogen plasma;
• and
• thereafter, etching the reduced graphene oxide membrane with electromagnetic radiation having a wavelength of about 400 nm to about 10 nm or with steam to generate pores of a predetermined size in the reduced graphene oxide membrane.