TiO2 NANOSTRUCTURES, MEMBRANES AND FILMS, AND APPLICATIONS OF SAME

Abstract

The present invention relates to applications of TiO 2 -containing, macro-sized nanostructures in the fields including photocatalysis, information writing-erasing-rewriting, microfiltration, controlled drug release, and tire making. In one aspect, the present invention relates to a method of photocatalytically decomposing organic pollutants. In one embodiment, the method includes the steps of mixing a solution containing organic pollutants and a plurality of TiO 2 -containing, macro-sized nanostructures to form a mixture and exposing the mixture to UV irradiation to decompose the organic pollutants.

1 - 11 . (canceled) 
     
     
         12 . A device of photocatalytically decomposing organic pollutants, comprising:
 a. at least one membrane or sheet formed with TiO 2 -containing, macro-sized nanostructures;   b. a container for receiving a solution containing organic pollutants and the membrane or sheet; and   c. a UV irradiation source positioned at a distance from the container for emitting UV irradiation onto the solution.   
     
     
         13 . The device of  claim 12 , further comprising a detector for measuring the concentration of the organic pollutants in the solution. 
     
     
         14 . The device of  claim 13 , wherein the detector comprises a UV-visible spectrometer. 
     
     
         15 . The device of  claim 12 , wherein the organic pollutants comprise nerve agents or nerve agent simulants (NAS). 
     
     
         16 . The device of  claim 15 , wherein the nerve agent simulants (NAS) comprise diethyl phenylthiomethylphosphonate (DPTMP). 
     
     
         17 . The device of  claim 15 , wherein the UV irradiation has a wavelength, λ, in the range of about 230 to 340 nm, and wherein the exposure time of the solution to the UV irradiation is in the range of about 1-60 minutes. 
     
     
         18 . The device of  claim 12 , wherein the TiO 2 -containing, macro-sized nanostructures are synthesized by:
 a. mixing an amount of TiO 2  powders with a volume of an alkali or alkaline solution to form a mixture; and   b. heating the mixture at a temperature greater than 160° C. for a period of time
 effective to allow TiO 2 -containing, macro-sized nanostructures to form, wherein the TiO 2 -containing, macro-sized nanostructures form in an environment that has no presence of a substrate that comprises Ti. 
   
     
     
         19 . The device of  claim 12 , wherein the TiO 2 -containing, macro-sized nanostructures comprise substantially nanofibers or nanowires with a typical diameter in the range of about 20 nm to 150 nm. 
     
     
         20 . The device of  claim 19 , wherein the nanofibers or nanowires are substantially in the TiO 2 -B phase or titanate phase. 
     
     
         21 . The device of  claim 20 , wherein the membrane or sheet comprises a layered structure. 
     
     
         22 . The device of  claim 21 , wherein the TiO 2 -containing nanostructures in each layer are at least partially intertwined, thereby forming three-dimensional (3D) voids therein. 
     
     
         23 . The device of  claim 12 , wherein the membrane or sheet is replacable by another membrane or sheet formed with TiO 2 -containing, macro-sized nanostructures. 
     
     
         24 . The device of  claim 12 , wherein the at least one membrane or sheet formed with TiO 2 -containing, macro-sized nanostructures comprises a first membrane or sheet and a second membrane or sheet positioned apart from the first membrane or sheet. 
     
     
         25 . The device of  claim 12 , wherein the membrane or sheet is disposable. 
     
     
         26 . A device usable for filtering micrometer-sized particles, comprising one or more filters made with a plurality of TiO 2 -containing nanostructures. 
     
     
         27 . The device of  claim 26 , wherein the plurality of TiO 2 -containing nanostructures comprises TiO 2 -containing nanofibers, nanowires, nanoriboons, nanobelts, nanobundles, or any combinations of them. 
     
     
         28 . The device of  claim 27 , wherein each of the one or more filters comprises a layered structure, and wherein the TiO 2 -containing nanostructures in each layer are at least partially intertwined, thereby forming three-dimensional (3D) voids therein. 
     
     
         29 . The device of  claim 27 , wherein the TiO 2 -containing nanofibers or nanowires are substantially in the TiO 2 -B phase or titanate phase. 
     
     
         30 - 56 . (canceled)