| Nanoscale zero valent iron (NZVI) possesses a small particle size and extremely high reactivitiy characteristics that make it prone to aggregate and may be self-ignite or oxidized when exposed to the air, Thes two major problems limit its application. To overcome these drawbacks, we proposed to design composite materials consisted of NZVI supported with ordered mesoporous carbon (OMC).In this article, NZVI supported on level hole ordered mesporous carbon (NZVI/OMC) composite materials was synthesized. Because of its ordered meso-structer, large suface area and big pore volume propertis, that may control the aggregation and oxidation of NZVI and optimize their reduction reactivity and stability. Level hole ordered mesoporous carbon can be synthesized by a solvent evaporation induced self-assembly method (EISA) by using a solube polymer of phenol and formadehyde (PF) as carbon precursors, silicate oligomers (TEOS) as inorganic precursors, and triblock copolymers F127as templates. By controlling the ratio of silica and carbon, the meso-pore size and specific surface can be touned. The NZVI/OMC composite can be synthesized by using OMC as supports, incipient wetness impergation of iron ion from ferrous sulfate, liquid phase reduction following previous calcination. NZVI/OMC composite material maintains the carrier material’s meso-structure, and the supported NZVI dispersed well with small size. The composite exhibites high adsorbtion ability and reduction property. The magnetically seperable Fe-containing mesoporous carbon composite materials (Fe/OMC) can be synthesized by using OMC as a earrier, di-solvent impergation of iron salts ferric nitrate, carbothermal reduction following previous calcination. The OMC and both composite materials were characterized by X-ray diffraction, transmission electron microscopy, N2adsorption-desorption and thermogravimetry. By choosing refractory nitrobenzene (NB) as a target pollutant, we investgated the synergistic effects of adsorption and reduction ability of NZVI/OMC. The adsorption behavious of Fe/OMC for cephalexin (CFX) pharmaceutical and personal care products (PPCPs) has been invaluated. Following results can be concluded.1. Ordered mesoporus carbon-silica nanocomposites possess ordered meso-structure, ordered mesoporous carbon can be obtained by etched in HF or NaOH solution. The material have large surface area of1870.01m2/g, and bi-modal pore size of2.5and3.46nm.2. The NZVI/OMC composite maintained ordered mesoporous structure. NZVI dispersed well on the matrix of carbon and iron species existed in a-Fe0state. NZVI/OMC composite exhibited more efficient removal effect for NB than both pure OMC and non-supported NZVI. The removal action of NZVI/OMC for NB was a combined synergistic effect of high adsorption capacity and significant reduction reactivity. The hydroxyaniline and dinitrosobenzene was the intermediant prouct and the aniliane was the final product. The removal efficiency of NB by NZVT/OMC increased as the dosage of NZVI/OMC increased. Acidic conditions was beneficial for the removal process. The adsorption and reduction effect would be hastened as the initalconcentration of NB increased.3. The odering of the Fe/OMC composite decressed with increasing the Fe concentration. Fe3+ions can be carbothermal reduction at800℃, and existed in α-Fe℃state. The nanometal particles with a diameter of10-50nm dispersed well in the carbon matrix. Nanometal iron have ferromagnetic, so the composite material having a good magnetic separation performance. At25℃, the saturation adsorption capacity of Fe/OMC for CFX was462mg/g, quasi-second-order rate equation can be used to describe the adsorption kinetics, and the Langmuir model can be used to describe the adsorption isotherm. |
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