Study On Regeneration Of Activated Carbon With Toluene By Microwave Radiatin

The absorption of low concentration toluene by granular activated carbon under different work condition was studied in the paper. The toluene was desorbed by irradiating the saturated granular activated carbon by microwave.Adsorption equilibrium can be well described by the Langmuir equation.Granular activated carbon was warmed quickly in the microwave field and the maximum was achieved in about 200 seconds. The activated carbon heating rate and the maximum temperature were proportional to microwave power, inversely proportional to activated carbon bed thickness and liner speed of carrier gas.The high temperature can desorbed more toluene than the low temperature ones. The desorption rate will not improved a lot when the temperature was above 400℃. Under the condition of liner speed of carrier gas14.7 cm/s, the desorption effect was best; liner speed of carrier gas7.3cm/s, the energy utilization ratio was highest. Different adsorptions of activated carbon need same time and energy to recovery to the same adsorption capacity. The optimum operating conditions were that desorption temperature 400℃, liner speed of carrier gas7.3 cm/s, activated carbon bed thickness 2cm. In this condition, after 50mins, the final desorption rate was 91.8%.The activated carbon ullage was very small, after regenerated five times; the total loss was less than 2.16%. After regenerated fifteen times, adsorption capacity was 79% of original capacity.In nitrogen atmosphere, activated carbon was modificated by microwave; it was beneficial to activated carbon to adsorp toluene. The modified temperature is higher, is more advantageous to the activated carbon to adsorp toluene. When toluene concentration was 7200 mg/m~3, the activated carbon adsorption capacity raised from 198mg/g to 226mg/g. Under the same modified temperature, the microwave modified activated carbon performance surpassed the electric heating modified activated carbon. The microwave modification had surface structure modification and surface chemical modification. At 450℃, the main function was surface structure modification. At 650℃, the adsorption capacity improve was casued by surface structure modification and surface chemical modification. At 850℃, the adsorption capacity improve was casued by surface chemical modification.According to the results, microwave desorption can recover adsorption capacity well, reduce the loss of the activated carbon, increase the concentration of toluene. In all the microwave desorption was worthy of being studied.