Method for preparing rice hull active carbon/silicon dioxide/titanium dioxide composite material

The invention discloses a method for preparing a rice hull active carbon/silicon dioxide/titanium dioxide composite material in the technical field of preparation of nano titanium dioxide photocatalysts. The method comprises the following steps of: carrying out acid cleaning on rice hull powder; adding an NaOH solution into the rice hull powder which is subjected to acid cleaning and carrying out alkali cooking to obtain mixed size consisting of rice hulls and sodium silicate; preparing a rice hull/silicon dioxide/titanium dioxide precursor; and finally carrying out carbonization and activating treatment to prepare the rice hull active carbon/silicon dioxide/titanium dioxide composite material. The rice hulls and nano titanium dioxide are combined in a chemical bond mode by silicon dioxide. The rice hull active carbon/silicon dioxide/titanium dioxide composite material not only has excellent adsorption performance of rice hull active carbon, but also has excellent photocatalysis performance of the nano titanium dioxide. The problem that the nano titanium dioxide is easy to fall off on the surface of a vector is effectively avoided. The stability of the composite material is greatly improved. The method has the advantages of simple preparation process, low price of raw materials, low cost and low pollution.