Surface Modification And Preparation Of Molecular Imprinting TiO₂and Its Properties

TiO₂photocatalytic oxidation degradation as a new, effective green technology,has a broad application prospect in the field of environmental protection and energysaving. But TiO₂itself has limitations, such as particle agglomerate, poor dispersion,the photocatalytic degradation of the lack of selectivity, therefore, in recent years thestudy of new catalyst which has high photocatalytic activity and is capable ofselective degradation of the target pollutants has attracted attention widely. Aiming atthe limitations of TiO₂itself, this paper has carried on the organic modification andmolecular imprinting.（1） Nano TiO₂powders was prepared by Sol-gel method and modified in situby the silane coupling agent KH-570（MPS）, then and then polyacrylamide （PAM）were grafted onto the surface of MPS-TiO₂powders by in situ graft polymerizationresulting the PAM/MPS-TiO₂nano composite material. The characteristic analysisshowed that: silane coupling agent was successfully grafted onto the surface of TiO₂its dispersibility was improved, lipophilicity and photocatalytic activity wasenhanced.（2） Using the self-made TiO₂powder as matrix, TNT as the template molecule,prepared molecularly imprinted TiO₂photocatalyst with TNT hole（MIP-TiO₂） bysurface molecular imprinting method. Photocatalyst was microsphere, had uniformparticle size and it was about1²μ m; when degradating the different pollutants thephotocatalyst using acrylamide as function monomer had high absorbent optic and theselective degradation is very good for the template molecule and its degradation ratecould reach80%when irradiating for2h; compared with nonimpringting catalyst,selective coefficient of imprinting catalyst was1.72, showing better selective degradation ability; after4times of repeated use, the reduction of photodegradationrate is smaller, molecularly imprinted TiO₂photocatalyst had a good life.（3） Molecularly imprinted TiO₂films（MIF-TiO₂） was prepared using2,4,6-threenitro toluene as template molecule by the liquid phase deposition, its reactionconditions were mild, MIF-TiO₂with specific recognition ability to the targetmolecule. Compared with NIF-TiO₂, the degradation rate of MIF-TiO₂increased by94.4%. Compared with the MIP-TiO₂powder photocatalyst, molecularly imprintedTiO₂film convenient recycling synthetic utilization, degradation rate reached63.3%in2.5h and had a good life.