Preparation Of Nano-ferrites And Nano-metal Co And Thier Adsorption Performance Of Congo Red

In this thesis, nanoferrites and Co nanomaterials were synthesized and their morphology was controlled by optimizing the composition and synthetic process. The synthesized samples were then applied as adsorbents in removal of Congo red. The main work and results are as follows:1. A rapid hydrothermal process has been introduced to prepare CoxFe3-xO4(0?x?2) nanoparticles.Single phase CoxFe3-xO4(0?x?2)without Fe2O3 has been successfully prepared through adjusting the ratio of Fe2+/Fe3+. The particle size and morphology can been controlled by Co content(x). The relationship between adsorption performance of Congo red and x has been studied. Co1.6Fe1.4O4 nanoparticles exhibit the largest specific surface area of 170.1 m2/g and the highest Langmuir maximum adsorption capacity, which is expected to be 370.4 mg/g for CR. Co1.6Fe1.4O4 nanoparticles are a potential recyclable adsorbent and can be regenerated and reused without significant decrease on CR adsorption capacity. The isotherm and kinetic models were also analyzed for CoxFe3-xO4(0?x?2)nanoparticles.2. Irregular MnFe1.6Sm0.4O4 nanoferrite has been successfully prepared via a hydrothermal process using PEG-4000 as the soft-templates. Branch-like MnSm0.4Fe1.6O4 nanostrucrures can be prepared by optimizing synthesis process. The as-synthesized branch-like MnFe1.6Sm0.4O4 is with a porous structure, and the uniform nanoparticles(around 50 nm) self-assemble and form the branch-like structure with an out-diameter of around 400 nm. The branch-like MnSm0.4Fe1.6O4 nanoparticles exhibit more excellent adsorption performance(removal efficiency of 99.4%) towards Congo red than the irregular nanoparticles(51.4%), due to its higher specific surface area and the porous structure. Furthermore, its high magnetization 55.9 emu/g makes it easier to be separated.3. Co nanoclusters with hcp structure were prepared by a chemical oxidation-reduction method.The structure, morphology, magnetic property and adsorption performance of Congo red were also investigated. The as-synthesized products were used to remove Congo red in different solvents(deionized water, ethanol, acetone and 50% deionized water+50% ethanol). Co nanoclusters in deionized water exhibit the best adsorption capacity and those in acetone show the worst. The adsorption performance is related to the dispersion ability of adsorbent in solvents as well as the surface energy of solvents.