Compound Modification And Photochemical Catalysis Property Of Nano-tio₂

Nano-TiO2 as an important inorganic functional material is widely applied in many fields. But nano-TiO2 has strong surface activity because of very big specific surface area and the serious deficiency of the coordination of nano-TiO2 particles so as to make them easy to accumulate. Nano-TiO2 particles without surface hydrophobic treatment display the hydrophilicity, cannot evenly disperse in organic medium. So the practical application effect of nano-TiO2 was greatly reduced.The single modification and compound modification of nano-TiO2 by using MMA as raw materials, lanthanum nitrate as modifiers were studied in this paper. The surface modification effect of nano-TiO2 was characterized by lipophilic degree, surface hydroxyl number and photocatalytic performance.It was showed that the compound modification effect of increasing the lipophilic degree of nano-TiO2 was best on basis of the lipophilic degree. The better conditions of the compound modification were:amount of MMA 44.1% by nano-TiO2 mass, reaction temperature 80℃, reaction time 60minutes, amount of lanthanum nitrate 2.3%, heat treatment temperature 500℃and heat treatment time 5 hours. The effect of the compound modification is also better than that of single modification on basis of the surface hydroxyl number. The better conditions of compound modification based on the surface hydroxyl number were:amount of MMA 44.1%, reaction temperature 80℃, reaction time 60 minutes, amount of lanthanum nitrate 2.3%,heat treatment temperature 500℃and the heat treatment time 5 hours too.The photocatalytic performance of the compound modification is better than that of the single modification on basis of the photocatalytic performance. The better conditions of the compound modification were:amount of MMA 44.1%, reaction temperature 80℃,reaction time 60minutes, amount of lanthanum nitrate 2.3%, heat treatment temperature 500℃, the heat treatment time 5hours and photocatalytic time 120 minutes. The infrared spectroscopy test showed that a proportion of hydroxyl groups on the surface of nano-TiO2 were replaced by the organic groups after nano-TiO2 being modified by the single modification, and these organic groups still exist after nano-TiO2 being modified by the compound modification. The accumulation became weak after nano-TiO2 was modified through SEM test. The doped lanthanide ions already entered into the r ano-TiO2 lattice by XRD.