Templated Synthesis Of Mesoporous Materials And Their Application

Mesoporous materials have regularly periodic pore structures, highly uniform andrelatively large pore size (2-50nm), large pore volume, high surface area andadjustable ordered stuctures. These prominent performances give the mesoporousmaterials tremendous applications in catalysis, adsorption and separation,biopharmaceutical synthesis, material assembly. In this paper, template methods wereused to synthesize mesoporous carbon and mesoporous alumina, and furthermore, theadsorption performance of mesoporous alumina in the removal of heavy metal ions inwater was studied.For the synthesis of mesoporous carbon, the resin prepared by phenol andformaldehyde as precursor, F127and P123triblock copolymer as template agents, thehighly orderd and stable mesoporous carbon was synthesized using soft templatemethod. The experiments emphasize on the influences of the template type, theamount of the template agent, calcination temperature and thermal polymerizationtime on the pore size, volume and surface area. The results show that orderedmesopores carbon could be obtained using the two kinds of surfactants and theamount of the template agent would change the mesostructure from hexagonal pore tocubic pore. The synthesis of ordered mesoporous carbon will lay the basis for thefuture work of biodiesel preparation catalyzed by a novel mesoporous carbon-basedsolid acid catalyst.For the synthesis of mesoporous alumina, the effects of different synthesismethods, the types and amounts of template agents, calcination temperature onmesostructure and pore parameters were mainly investigated. The results suggest thatusing the sol-gel method, mesoporous alumina with worm-like channels could besynthesized with Triton X-100surfactant as the template; meanwhile, using ethanolevaporation-induced self-assembly (EISA) method, highly orderly mesoporousalumina could be achieved with PEO-PPO-PEO triblock copolymer as template.Moreover, the functions of gel systems such as GP-1organogel and agarose hydrogelon the structure construction of mesoporous alumina were investigated. On the basisof different template syntheses, macroporous-mesoporous alumina was furtherobtained with agarose xerogel as the macropore template and triblock polymer as themesopore template.Heavy metal ions in the water can not be biodegraded, which bringsserious harm to environment and public health. In our work, the prepared mesoporous aluminaswith different kinds of pore structures were used to remove heavy metal Cr(VI) inwater, compared with the performance of commercial alumina adsorbent. Theinfluences of pH value, adsorbent dosage and types on adsorption performances ofadsorbents were mainly studied. The adsorption dynamics and adsorption isothermwere also simulated. The results show that the aluminasynthesized by EISA methodexhibits the best adsorption performance. The removal percentage of Cr(VI) reaches99%after100minutes and the maximum adsorption capacity of Cr(VI) reaches46mg/g with Langmuir fitting, which confirms the accordance of microscopic structureand macroscopic performance.