The Preparation And Application Of Fenton Catalyst—Ordered Mesoporous Carbon Supported With Iron

The technique of supported Fenton catalysis is an effective approach to degrade organic pollutants. It overcomes the drawbacks of homogeneous Fenton system, such us being limited by pH, bringing about large amounts of sludge, and receives much attention. Simultaneously, ordered mesoporous materials have the potential of good catalyst for it owns excellent properties such as large specific surface area, large pore volume, highly ordered porous, single pore size distribution and tunable pore diameter size within2-50nm. In this paper, we proposed to design two kinds of composite materials, ordered mesoporous carbon (OMC) coated iron and OMC supported iron, using soft template method with OMC as support and ferric nitrate as iron precursor. The obtained materials were characterized by X-ray diffraction (XRD), nitrogen adsorption-desorption techniques and transmission electron microscopy (TEM). Choosing phenol as a target pollutant with the two composite materials as Fenton catalyst, we studied the catalytic performance of the two sample materials. This study may provide useful information to further develop some effective heterogeneous catalysts for the degradation of organic pollutants. The main conclusions are as follows:(1) The coated Fe/OMC-x composite materials had high structure order degree. It owned two-dimensional mesoporous structure and narrow pore size distribution. Iron species existed in α-Fe0states and dispersed uniformly in the carbon substrate.When the concentration of H2O2is4080mg/L, the Fe/OMC-x-0.05dosing of2g/L, the temperature of60℃, the initial pH of3.0,87.2%of100mg/L phenol could be moved after4h. When phenol concentratin decreased to50mg/L, it reduced to94.1%. The phenol removal rate reduced from87.2%to67.9%in the third cycle.The leaching rate of active components was3.6,8.7and8.3%, respectively and TOC removal reduced dramatically. It indicated that the coated Fe/OMC-x composite materials had poor catalytic performance, stability and reusability.(2) The supported Fe/OMC-y composite materials had ordered two-dimension hexagonal mesoporous structure and narrow pore size distribution. When the calcination temperature was600℃, iron species existed in γ-Fe2O3states. When it was700℃, iron species existed in α-Fe0and γ-Fe2O3states, the particle size of γ-Fe2O3decreased. Iron species just existed in α-Fe0states when the calcination temperature was800℃, the particle size of α-Fe0increased. When the supported Fe/OMC-y composite materials was used to degrade phenol, phenol was adsorped quickly, then degraded gradually in the channel. When the concentration of H2O2is4080mg/L, Fe/OMC-700dosing of2g/L, the temperature of25℃, the initial pH of not being adjusted,97.8%of phenol of50mg/L and TOC could be moved after24h. And it had no significant decline in the recycling. The leaching rate of iron was within2.5wt.%. These results indicated that the supported Fe/OMC-y composite materials had good catalytic performance, stability and reusability.