Preparation Of Graphene-based Membrane Materials And Their Application In Water Treatment

Graphene,a new class of carbon-based materials,has received great attention and research by investigators.Graphene has a structure of two-dimensional honeycomb lattice stacked tightly by the monolayer of carbon atoms.Due to the sp2 hybridization of carbon atoms,graphene is generally presented as having a flat,planar configuration.The advantageous film-forming property of graphene makes it posses potential application in membrane materials field.Simultaneously,due to the very superior teleportation ability,graphene also receive more and more attention in photo catalysis field.This dissertation will take advantage of the film-forming property and the photocatalysis enhanced property of graphene comprehensively,use graphene oxide,the derivatives of graphene,as precursor to prepare graphene oxide-based composite membrane material,and research the application of these membranes in wastewater treatment.The dissertation is mainly focused on:(1)We used graphene oxide sheets as carriers and loaded with TiO2 nanoparticles,and then reassembled the graphene oxide-TiO2 composite sheets,forming graphene oxide-TiO2 composite membranes.Because of the insertion of nanoparticles between graphene oxide sheets,the special two-dimensional channels in the as-obtained composite membranes were expanded,improving the permeate performance of the composite membranes.The quality of loaded nanoparticles can be adjusted by changing the amount of graphene and titanium salt.With the increase of dosage of TiO2,the permeability of membranes will be better.Because the crystalline degree of Ti02 is low,the photocatalytic performance of membrane is not very well.We immobilized a layer of P25 on the graphene oxide-TiO2 composite membranes by simple filtering methods.Graphene oxide-TiO2 composite membranes possess self-cleaning property under ultraviolet light,and the retained dye molecules were decomposed soon.(2)Graphene can not only be assembled into graphene filtration membrane but also served as a kind of membrane filing agent.We assembled TiO2 nano wires into filtration membranes with large pore diameter,and then added a certain proportion of graphene oxide.Graphene oxide can be dispersed relatively homogeneous in the membranes.After the reduction and the chemical converted graphene was obtained.Because of the existence of graphene,the pores in the membranes which were assembled by TiO2 nanowires were partly plugged up.Because of the addition of graphene,the absorbability of the filtration membranes was getting strengthened.With the increase of graphene dosages,the absorbability of filtration membranes towards direct yellow dye increased.TNW-G composites possess a certain photodegradation property for direct yellow solution under the irradiation of ultraviolet light.