Synthesis Of Rare Earth Chromites And Research Of Mesoporous Materials On Reducing The Release Amount Of Chromium And Cadmium In Cigarette Smoke

In this thesis, we focus on two items:the rare-earth chromites micromaterials were synthesized by a hydrothermal method, including orthorhombic PrCrO3cubic particles and orthorhombic elliptic NdCrO3microplates. The materials were characterized by XRD, XPS, FTIR and FESEM. The reaction conditions preparing the compound with idealer structure and morphology were optimized. The possible growth mechanisms of the materials with optimum morphologies were proposed. Their magnetic properties were also explored. On the other hand, the mesoporous composite EDTA-4Na/y-Al2O3has been synthesized by a soakaging method. The material was characterized by TG, XRD and TEM. The application of the material for reducing the release amount of heavy metals in cigarette mainstream smoke was explored. The main research work of this thesis can be summarized as follows:(1) Orthorhombic PrCrO3cubic particles with high crystallinity were synthesized by a one-step hydrothermal method. The obtained products were characterized by XRD, XPS, FTIR and FESEM. The conditional experiment results showed that280°C,7days, the molar ratio of Pr3+to Cr3+of1:1and the alkalinity of the solution of8mol/dm3were the preferable experiment parameters to synthesize the PrCrO3cubic particles. The possible growth mechanism of the PrCrO3cubic particle was researched. The magnetic properties of the matetial were also explored. The research result showed it exhibited behaviors of magnetic transition and negative magnetization. Its Neel temperature was232K. and the magnetic hysteresis loop under4K showed that its coercivity and remanence was about1728Oe and4.88emu/g. The parameters were a little different from those of the previously reported materials, it may be due to the different morphologies or sizes. However, more detailed studies were required to understand its magnetic properties in depth. Orthorhombic NdCrO3particles were synthesized by a similar method. The conditional experiment results showed that280°C,3days, the molar ratio of Nd3+to Cr3+of0.56:1and the alkalinity of the solution of8mol/dm3were the preferable experiment parameters to synthesize the elliptic microplates. The possible growth mechanism of the elliptic NdCrO3microplate was researched. The magnetic properties of the matetial were also explored.(2) The mesoporous composite EDTA-4Na/y-Al2O3has been synthesized by a soakaging method. The structure and performance of the material were characterized by TG, XRD, TEM and so on. The mesoporous composite EDTA-4Na/y-Al2O3was added to the two element composite filter rods, its effect on reducing the release amount of Cr and Cd in cigarette mainstream smoke was examined. The results indicated that the release amount of Cr and Cd in cigarette mainstream smoke can be reduced by33.2%and31.1%as the mesoporous composite EDTA-4Na/y-Al2O3was added to the two element composite filter rods by16.25mg per filter-tip. The possible mechanism of reducing Cr and Cd release amount in cigarette mainstream smoke was also discussed. It mainly included two kinds of mechanisms of adsoptive retention and complex retention.