Sol-gel and electrospinning techniques are incorporated to produce titanium (IV) oxide/polyvinylpyrrolidone (PVP) composite nanofibers from solution containing PVP and titanium tetraisopropoxide. After calcination of the composite fibers, titania nanofibers are obtained. The average diameters of the obtained titania fibers is 165 nm with average pore size diameter of 50 A. Surface modification of titania by surfactant can be done by adsorption of the surfactant, whereas the adsorption depends upon type of surfactant, pH of the surfactant solution and surface charge of titania. The modification was subsequently used as adsorbent in the removal of phenylurea herbicides. i.e. diuron, isoproturon and linuron. Adsolubilization of herbicide taking place on the surfactant-modified titania assists the removal efficiency. Effectiveness of the adsolubilization depends upon various parameters, such as temperature, pH of the herbicide solution and adsorbent dose. Regeneration of used titania by photooxidation is possible, but complete degradation of the adsorbed organic compounds was not achieved after 6 hours of the photooxidation.

Thesis (M.Eng.)--Chulalongkorn University, 2006