Process for producing composite material
A process is disclosed comprising, providing a source of graphene, providing a particulate material, dispersing a mixture of the source of graphene and the particulate material in a first dispersion fluid to form a dispersion mixture, and providing a source of a base in the first dispersion fluid, thereby causing the source of graphene and particulate material in the dispersion mixture to interact forming a composite. The particulate material is preferably titanium dioxide comprising anatase and/or rutile which provides an effective photocatalytic composite. Also disclosed is apparatus to remove pollutants from fluids using the photocatalytically active material.
1 . A process for producing a flocculated composite product, the process comprising:
a) providing a source of graphene, wherein the source of graphene is selected from pristine graphene and partially oxidised graphene;
b) providing a particulate material, wherein the particulate material is a metal oxide,
c) dispersing a mixture of the source of graphene and the particulate material in a first dispersion fluid to form a dispersion mixture, and
d) providing a source of a base which comprises a source of hydroxide ions in the first dispersion fluid, wherein the source of hydroxide ions is provided at an amount of 0.5 millimoles to 20 millimoles per 10 g of the metal oxide;
wherein the addition of the source of a base causes the source of graphene and particulate material in the dispersion mixture to interact forming a flocculated composite product; and wherein the process is performed in the absence of a surfactant.
2 . The process as claimed in claim 1 , wherein the particulate material is a photocatalytic metal oxide.
3 . The process as claimed in claim 2 , wherein the photocatalytic metal oxide comprises titanium dioxide.
4 . The process as claimed in claim 1 , further comprising homogenising the dispersion mixture.
5 . The process as claimed in claim 1 , further comprising homogenising the source of graphene in a graphene dispersion fluid.
6 . The process as claimed in claim 1 , further comprising homogenising the particulate material in a material dispersion fluid.
7 . The process as claimed in claim 1 , wherein the source of graphene and the particulate material are mixed in a ratio of 3 to 500 parts by weight of the particulate material to 1 part by weight of the source of graphene.
8 . The process as claimed in claim 1 , wherein the composite has an I (D)/I (G) ratio at a laser excitation wavelength of 532 nm at 2.33 eV of less than 0.75.
9 . The process as claimed in claim 1 , wherein the first dispersion fluid comprises one or more of dimethyl sulfoxide, acetone, water, tetrahydrofuran, Chloroform, N-methyl-2-pyrrolidone, dimethylformamide, dimethylacetamide, gamma-butyrolactone, 1,3-dimethyl-2-imidazolidinone, Benzyl Benzoate, N-vinylpyrrolidone, N-dodecyl-2-pyrrolidone, n-propanol, isopropanol, and N-octyl-2-pyrrolidone.
10 . The process as claimed in claim 1 , wherein the particulate material has a particle size in the range of 5 nm to 1 μm.
11 . The process as claimed in claim 1 , further comprising recovering the flocculated composite product, and optionally recovering the dispersion fluid.
12 . The process as claimed in claim 1 , wherein the process is conducted at a temperature in the range of 0° C. to 260° C.
13 . The process as claimed in claim 1 , further comprising homogenising the dispersion mixture with a high shear mixer.