Study On Photocatalytic Degradation Of Toluene - Activated Carbon

Organic waste gases from combustion offuel and the technological process are the main source of atmospheric pollution. Activated carbon was used as a good adsorben because of their high specific surface area, variety of porosity, rich surface chemistry and huge adsorption capacity. Activated carbon saturated with benzene and toluene belongs to hazardous waste, and will cause serious environmental pollution and resource waste if they were thrown out. Therefore, studing on the regeneration of spent activated carbon is necessary. The photocatalytic regeneration is recognized as a high-efficiency and energy-saving regeneration technology, and has the vast development foreground.In this paper, the adsorption toluene saturated activated carbon was regenerated by gas phase photocatalysis and iodine-doped TiO2 as catalyst.Firstly, toluene desorbed on activated carbon was stripped by air and then was degraded. Adsorption value of methylene blue of regenerated carbon was evaluation standard. The influence of the mass ratio of activated carbon and catalys, gas flow rate, reaction time, the frequency of regeneration, bed height of activated carbon and reactor diameter on rate of regeneration were investigated, and the influence of the kind of the catalyst, the quality ratio of activated carbon and catalyst, gas velocity and regeneration modes on the removal rate of toluene in gas phase were studied using small photocatalytic reactor. On this basis, designed a photocatalytic reactor. The influence of the mass ratio of activated carbon and catalys, gas flow rate, the quality of activated carbon, regeneration time of activated carbon and reuse of catalyst on regeneration rate was discussed and the validation was done by the actual sample.The main results were as follows:(1)The regeneration rate of activated carbon saturated with toluenewas more than 83% when the mass ratio of activated carbon and catalyst was 0.1 and the gas flow rate at 12L/min, bed height was 2cm, and the diameters of the reactor was 1cm.(2)The regeneration rate of Bi20TiO32/TiO2 heterojunction was higher than it of I-TiO2.(3)The removal efficiency of toluene in gas can be above 84% by photodegradated for 3h under 300W UV lamp.The removal efficiency of toluene agrees with the results of regeneration rate of activated carbon.(4)In the amplifying device, the removal efficiency of toluene in gas was 82.06% when the mass ratio of activated carbon and catalyst was 0.4 and activated carbon saturated adsorption liquid toluene; the removal efficiency of toluene in gas was 88.08% when activated carbon saturated adsorption toluene in gas and the same as regeneration conditions. And after repeated 10 times, the regeneration rate of activated carbon is 81.23%, showing good reusability. Catalyst can be reused.