Synthesis Of Ni（Fe₃O₄） Loaded Magnetic Mesoporous Carbon Materials And Their Applications In Adsorption

With concerns growing regarding the environment and human health, technologieswith high efficiency and low-cost to reduce the pollutant contents of wastewater areurgently needed. Adsorption technologies were recently developed to solve theseenvironmental problems, which are regarded as reliable alternatives due to theirsimplicity, high efficiency, and ease of operation as well as the availability of a widerange of adsorbents. Activated carbon is frequently used as adsorbent for waterpurification because it’s large specific surface area and abundant micropores. However,such application unavoidably suffered from some limitations, such as the separation ofactivated carbon powder and low adsorption capacity. In this regard, orderedmesoporous materials may be the answer. To solve the problem of the complicatedseparation process after adsorption, mesoporous materials are always fabricatedincorporating with magnetic nanoparticles. The composites can not only remove manykinds of dyes and metal ions from polluted effluent liquors, but also be easily separatedby magnets. However, the preparation of magnetic mesoporous materials with largesurface area still remains a key challenge. In addition, most of the preparation methodssuffered from tedious processes, and low yield. In order to overtake these drawbacks,we developed a facile “sol-gel” synthesis route and a nano-casting method to preparemagnetic mesoporous carbon materials with large surface area and high magnetizationsaturation. The materials exhibited good ability for adsorption of dye molecular in thebatch adsorption experiments.In this thesis, two kinds of magnetic particles embedded mesoporous carbonmaterials were synthesised. One is Ni embedded mesoporous carbon and the other isFe₃O₄loaded mesoporous carbon, which were devided into two parts:The first part: magnetically separable Ni embedding on graphitic mesoporouscarbon （Ni/mC） materials were fabricated through a "sol-gel" route by using glucose,nickle nitrate, EO₂0PO70EO₂0（P123） and tetraethyl orthosilicate （TEOS） as carbonresource, catalyst and magnetic precursor, soft template and porogent, respectively. Theobtained Ni/mC materials exhibited highly graphitic degree with high surface area of790m²g^-1, large pore size at3.9nm and large pore volume of0.69cm³g^-1. Moreover,the saturation magnetization was enhanced to6.82emu g^-1 because of the aggregationof magnetic Ni nanocrystals into clusters. The Ni/mC materials showed excellentadsorption property for Rhodamine B and the adsorption capacity reached to168.1mgg-1within120min. Mesoporous carbon （mC） without adding nickle nitrate were alsoprepared by the same procedure to compare the adsorption properties with the obtainedNi/mC materials. In addition, hard template method was also applied to synthesizeNi/mC materials.The second part: magnetic Fe₃O₄@nSiO₂/mSiO₂nanoparticles were synthesized in an acid condition, which possess high BET surface area (847m²g^-1) and large porevolume (0.9cm³g^-1). Its superparamagnetic property with saturation magnetization of8.52emu g-1made it easily separated by an external magnetic field. The obtainedFe₃O₄@nSiO₂/mSiO₂particles were then used as hard templates to synthesize Fe₃O₄embeded mesoporous carbon （Fe₃O₄/mC）. It is noteworthy that Fe₃O₄/mC hadexceptionally large surface area up to960m²g^-1and pore volume of1.25cm³g^-1. Thehigh surface area and mesoporous structure of Fe₃O₄/mC favor its adsorption of dyemolecular in aqueous solution. Fe₃O₄/mC exhibited an excellent adsorption capacity;moreover it was easily separated by the external magnetic field and reused after ethanolextraction. The rapid and efficient adsorption of Rhodamine B and easy separation andregeneration suggest that Fe₃O₄/mC hybrids have great potential applications inenvironmental pollution abatements.