Polyaniline/titanium dioxide/clay nanometer composite photocatalyst and preparation method thereof

Abstract

The invention relates to a nanometer TiO2 photocatalyst, in particular to a polyaniline / titanium dioxide / clay nanometer composite photocatalyst and a preparation method thereof. Titanium tetrachloride and clay are firstly used as raw materials, an in-situ synthesis method is adopted for preparing nanometer titanium dioxide / clay composite material, hydrochloric acid generated by titanium tetrachloride hydrolysis is used for providing the acid environment required by aniline polymerization, the polyaniline conductive polymer loaded titanium dioxide surface is synthesized, the conductive polyaniline is used for receiving electrons generated by the photon excitation on the titanium dioxide, the electron-electronhole pair compounding is inhibited, and the photocatalytic performance of the composite material is improved.

Description

technical field [0001] The present invention relates to nanometer TiO 2 The photocatalyst specifically refers to a polyaniline / titanium dioxide / clay nanocomposite photocatalyst and a preparation method thereof. Background technique [0002] Photocatalytic oxidation technology is an emerging modern environmental pollution control technology. Its principle is to irradiate semiconductor materials with light whose energy is equal to or greater than the band gap of semiconductor materials, so that the electrons on the valence band (e - ) is excited to transition to the conduction band, generating corresponding holes in the valence band (h + ), photo-induced holes (h + ) has a very strong ability to gain electrons, and the OH adsorbed on its surface - and H 2 O is oxidized to hydroxyl radicals (OH), and the standard oxidation potential of OH is 2.8eV. It is the strongest oxidant except elemental fluorine, and can completely oxidize most organic substances to CO without select...

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Problems solved by technology

The suspended state is to suspend the nano-titanium dioxide catalyst evenly in the form of powder in the reaction solution. Since there is almost no mass transfer resistance and the catalyst particles have a large specific surface area, the organic pollutants can fully contact or be easily transferred to the surface of the catalyst particles. It has a higher catalytic efficiency, but due to the small particle size of nano-titanium dioxide, it is easy to lose, and the separation and recovery of the catalyst in the later stage are difficult, making it difficult to be widely used in actual wastewater treatment; catalyst fixation is to use appropriate methods to fix the catalyst. On a suitable carrier, the carrier for immobilizing the catalyst generally includes light-transmitting glass (sheet, tube, ring, bead), quartz fiber, quartz particle, activated carbon, stainless steel and alloy, etc., but the immobilization of the catalyst solves the problem of the suspension state. At the same time, new problems have also arisen, such as the limited effective surface area of ​​organic pollutants in contact with the catalyst, and the existence of mass transfer resistance, so the catalytic efficiency is lower than that of the suspended state

The second is the problem of photocatalytic activity. Since the electron-hole pairs generated by light are easily recombined to generate heat, the number of hydroxyl radicals generated in the photocatalytic process is reduced, and the photocatalytic activity is reduced. Therefore, in recent years, the development of new high-efficiency photocatalysts has become increasingly It has attracted more and more people's attention; a lot of research has been done on improving the photocatalytic activity of titanium dioxide in recent years. Chinese patent CN101721990A discloses a preparation method of a double rare earth element La and Y doped TiO Tetrabutyl nitrate, lanthanum nitrate and yttrium nitrate were used as raw materials, first prepared into a gel, then dried at 60°C to obtain a xerogel, and finally calcined at 400~700°C to obtain La and Y co-doped TiO 2 Photocatalyst, this method requires high temperature calcination, which increases the cost and leads to the agglomeration of nanoparticles. Chinese patent CN101362087A discloses a preparation method of noble metal modified titanium dioxide photocatalyst, by depositing Ag, Au, Noble metals such as Pt and Pd promote the separation of photogenerated electron-hole pairs and improve the activity of titanium dioxide photocatalysts, but the expensive metals such as Ag, Au, Pt and Pd used in this method limit their popularization and application

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