.pd / Tio <sub> 2 </ Sub> Nanomaterial Preparation, Characterization And Environmental Applications

In this thesis, environment contaminations,such as formaldehyde, (o,m,p-) omethyphenol and some heavy-metal ions are used as substance for the test of photocatalytical ability of TiO₂.The modification of TiO₂ with Pd-dopping,the immobilization methods of TiO₂ and surface absorption behavior of TiO₂ were studied in detail.A modified TiO₂ precursor technique was developed for the preparation of TiO₂ and Pd/TiO₂ loaded on MCM,and Pd/TiO₂ particles were characterized by means of SEM,TEM,XRD,UV-Vis,IR and Raman spectroscopy. Controllabe particle size of Pd/TiO₂ is from 8.3nm to 25 nm. The experiment results showed that MCM-Pd/TiO₂ with a Pd-doping amount of 1% possesed the best photocatalytic activity. methylphenol in concentration of 1×10^-4molL^-1 could be completely degraded under 40W UV illumination for 3 hours with the air bubbling at 120ml/min. Additionally,the photocatalysts of single or double elements doping were prepared respectively,and their corresponding photocatalytic were investigated.Thin films of TiO₂ consisted of different percentage of Pd loaded on a tiny-aperture glass were prepared,and photocatalytic degradation of omethoate pesticides using obtained Pd/TiO₂ films was studied.The results showed that photocatalyst calcined at 400℃ for 2.5 hours gave higher activity when the sol containing 15% PEG and l%Pd was used.All omethoate in concentration of 1×10^-4molL^-1 could be degraded over the catalyst under 40W UV lamp illumination for 5 hours.and the Pd/TiO₂ thin film possesses better stability and the long life time,the regeneration of the Pd/TiO₂ thin film could be done by washing with 10^-2molL^-1 NH₃ . H₂OAbsorption behaviors of Cu²+,Cd²+ and Pb²+ ions on nano-β-CD-TiO₂ and β-CD-Pd/TiO₂ were studied by QCM.The results showed that absorption amount of modified TiO₂ by doping β -CD was enhanced .Absorption model was proposed to describe the absoption process of them. This kind of absorption belongs to A Langmuir,and Γ_max for Cu²+,Cd²+ and Pb²+ on β-CD-TiO₂ were 1.035×10^-4molg^-1,1.089× 10^-4 molg^-1 and 1.091×10^-4 molg^-1 respectively, but 1.530×10^-4molg^-1,1.341X lO^molg"1 and 1.273 X lO^molg1 for those ions onJ3-CD-Pd/TiO2 respectively.