Composite film with photocatalytic oxidability and preparation method thereof

Abstract

The invention discloses a composite film with photocatalytic oxidability and a preparation method thereof. The preparation method comprises the following steps: preparing titanium dioxide / carbon nanotube powder through glue melting and condensation, and uniformly dispersing the titanium dioxide / carbon nanotube composite material into acetic acid solution of chitosan with the chitosan as a crosslinking agent, wherein the mass ratio of the chitosan and the titanium dioxide / carbon nanotube is 1 to 10, thereby obtaining the catalytic film made of titanium dioxide / carbon nanotube / chitosan material. The composite film prepared in the method is uniform, the preparation method is simple, the raw materials are cheap, and the sources are rich. The defect structure of the surface of the raw carbon nanotube provides growing points for the growth of titanium dioxide grains. In addition, the adsorbed organic substances and intermediates of photodegradation have the function of coordinating with functional groups of the chitosan. The composite catalytic film provided by the invention can be used for photocatalytic oxidation of volatile organic compounds (VOCs) under the visible light irradiationwith the wavelength more than 350nm, and can be used as the air purification agent, the industrial waste water treatment agent and the like.

Description

technical field [0001] The invention relates to a carbon nanotube / titanium dioxide / chitosan composite film with photocatalytic oxidation and a preparation method thereof, belonging to the technical field of preparation and application of nanometer photocatalysts. Background technique [0002] Indoor volatile organic compounds (VOCs) removal methods mainly include activated carbon adsorption, plant purification, electrostatic dust removal, photocatalysis, etc. At present, as a new technology, photocatalysis has become a research hotspot in the field of indoor air quality. Photocatalytic materials can generate free electrons (e - ) and holes (h + ), can oxidize and decompose organic compounds and some inorganic substances, and has strong antifouling, sterilization and deodorization functions. [0003] TiO 2 Photocatalytic oxidation technology is based on the theory of N-type semiconductor energy bands, and its essence is to carry out redox reactions in photoelectric convers...

AI Technical Summary

Problems solved by technology

e - with h + Separation occurs and migrates to different positions on the grain surface of the particle, so that the photoinduced electrons on the conduction band e - With strong activity, a redox system is formed on the surface of titanium dioxide; at the same time, a photoinduced hole h is formed on the valence band + , the photo-induced holes on the valence band have strong oxidative properties, and the hydroxyl radicals (OH) produced by redox reactions with moisture and oxygen in the air have very strong oxidizing ability, and the free radicals oxidize and decompose VOCs to generate CO 2 and H 2 O, but e - with h + Surface recombination can also occur, resulting in reduced photocatalytic degradation ability

[0004] There are mainly two types of composite material catalysts prepared in the past. One is carbon nanotube / titanium dioxide composite material. The prepared composite material is in powder form.

The other is the preparation of titanium dioxide / chitosan composite materials. This method has high requirements on light due to the photocatalytic degradation of the preparation, and because the specific surface area of ​​the prepared composite material is small, the catalytic effect of catalytic pollutants is not ideal.

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