| The discharge of dye into the environment was currently one of the world’s major environmental problems for both toxicological and esthetic reasons. Adsorption was considered as the most promising option. Selecting a suitable adsorbent was the important guarantee for absorption processes. Pore structure was one important factor that affected the adsorption performance to pollutants. Although activated carbon was the most widely used adsorbent, it was restricted by its microporous nature, resulting in distinct low adsorption capacity of large-sized organic dyes on the activated carbon.Recently, mesoporous carbons materials with open pore structure and large pore size have showed remarkable improvement in the adsorption of bulky dyes over commercial activated carbons. The functional magnetic mesoporous carbon materials with fast adsorption and separation behavior have been extensively used in pollution abatement.Besides the pore size and structure, the surface composition of the adsorbent also affected the adsorption performance.In this thesis, there were two N-functional mesoporous carbon materials synthesised. One is only N droped mesoporous carbon Fe3O4@N-m C and the other is N/O droped mesoporous carbon Fex Oy@N-O-m C. The following is a detail.The first part: Nitrogen-doped magnetic mesoporous carbons Fe3O4@N-m C was obtained from carbonization of magnetic mesoporous polyaniline fabricated by aniline polymerization around modified Fe3O4 particles, surface modification and magnetic property were successfully introduced into the mesoporous C. Similar sizes of acidic MO and basic MB and bulky Rh B were selected to investigate the influences of molecular size and acidic/basic property of dyes on adsorption performance of Fe3O4@N-m C. Due to its spacious mesoporous structure and functional basic character,Fe3O4@N-m C displayed the adsorption ability in order of MO > MB > Rh B, favoring the adsorption to acidic dye over basic dye with the similar size. The surface chemical interaction and pore diffusion were the rate-determining steps in the whole adsorption process. Moreover, the introduced magnetic Fe3O4 made the composite easily separated after adsorption and regenerated with excellent stability. The facile synthesis procedure,fast and high adsorption performance, easy separation and excellent regeneration made Fe3O4@N-m C promising candidate in practical wastewater treatment.The second part: Nitrogen-/oxygen-doped magnetic mesoporous carbon(Fex Oy@N-O-m C) was prepared by nanocasting, using sucrose and urea as carbon and nitrogen source and core-shell Fex Oy@m Si O2 as hard template. Oxygen-doped magnetic mesoporous carbon(Fex Oy@O-m C) was prepared by the same procedure using only source as carbon source. MO, MO, Rh B were also selected as probemolecules to investigate the dye adsorption behavior on the two mesoporous carbons and activated carbon. Due to its spacious mesoporous structure and functional basic character, Fex Oy@N-O-m C displayed the adsorption ability in order of MO > MB >Rh B, consistent with Fe3O4@N-m C. In addition, this novel functionalized adsorbent could enhance the adsorption capacity of the acid dye by 90-200% and 10-15%compared to the commercial activated carbon and unmodified mesoporous carbon,respectively. This significant improvement was attributed to the enhanced dispersive forces between the carbon surface and the dye molecules induced by the nitrogen-containing functional groups. However, Fex Oy@N-O-m C displayed a lower uptake in basic dyes also owning to its basic nature. The surface chemical interaction and pore diffusion were the rate-determining steps in the whole adsorption process.Moreover, the introduced magnetic Fe3O4 made the composite easily separated after adsorption and regenerated with excellent stability. The facile synthesis procedure, fast and high adsorption performance, easy separation and excellent regeneration made Fe3O4@N-m C promising candidate in practical wastewater treatment. |
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