| The deterioration of environment, especially the atmosphere pollution, resulting from the developing of industrialization, has become one of the city’s environment problems to be solved. The discharge of industrial waste gas, especially organic waste gas, is one of the main sources of atmosphere pollution. Representative of aromatic compounds is a kind of highly toxic industrial waste gas Adsorption is a commonly used effective method for environmental pollution treatment. Active carbon is widely used adsorption materials due to its developed hole structure and prodigious surface area as well as adsorption capability. The saturated adsorption of activated carbon reoperation process is need. Photocatalytic regeneration has huge potential as a high efficiency, energy-saving and time-saving regeneration technology.In this paper, I-TiO2/activated carbon composite catalysts were prepared through sol gel and dipping method. The influences of adsorption performance on modified activated carbon and regeneration were investigated. The surface physicochemical characteristic of the I-TiO2/AC was studied with kinds of measurement technologies such as XRD, SEM, BET surface area, FTIR, Boehm titration, adsorption ability of methylene blue and the amount of TiO2supported on the active carbon. Toluene as the target pollutant, the effect of initial concentration, gas flow, and bed length and particle size on the breakthrough curves was studied. Through the self-regulation gas-phase photocatalysis reaction device, photocatalysis activity and regeneration efficiency was estimated with measured toluene removal efficiency by gas chromatography. And compared with liquid phase photocatalytic regeneration effect. The components of in the process of photocatalytic degradation were detected on line by GC, FT-IR and UV. The following are the main experiment conclusion:(1) The doped I-TiO2supported on activated carbon was calcined at300℃, the average particle diameter of resultant I-TiO2was about6.7nm, its crystal form was anatase, and the surface area was208.98m2·g-1.I-TiO2had little influence on the microstructure of active carbon.(2) With the increase of initial concentration of toluene, the penntration time was shorter. Gas flow on the shape had little impact on breakthrough curves. The shape of breakthrough curves was not affected by the bed height. Yoon-Nelson model could simulate the adsorption process. I-TiO2loaded had little influence on the adsorb ability of active carbon.(3) Saturated toluene adsorption of I-TiO2/AC could be in situ regenerated illuminated with ultraviolet light in homemade gas phase photocatalytic reaction device. The MB adsorption capacity of I-TiO2loaded activated carbon could be recovered by68.98%when sample irradiated for4h under250W UV lamp, the toluene removal efficiency was about85.2%in photocatalytic oxidation process. Recycled three times repeatedly, the regeneration efficiency of I-TiO2/AC was nearly unchanged. The gas phase composition other than toluene had not found in the process of photocatalytic degradation(4) Saturated toluene adsorption of I-TiO2/AC could be in situ regenerated under illuminated with visible light in the liquid-phase photocatalysis reaction device. The MB adsorption capacity of I-TiO2loaded activated carbon could be recovered by51%when sample irradiated for4h. The regeneration efficiency of I-TiO2/AC was nearly unchanged when I-TiO2/AC was reused for3times. The main intermediates were phenol and benzoic acid during the toluene degradation. |
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