Characteristics Of Adsorption/desorption And Discharge Degradation Of Toluene By Conductive Biomass Char With High Specific Surface Area

The conductive biomass char (CBC) with high specific surface area was obtained with precursor of corn cob. Experiments were performed with toluene as model pollutant. The adsorption and desorption characteristics as well as discharge degradation of toluene adsorbed on CBC were studied, with the operating parameters optimized. The main research work and detailed results are as follows:(1) High specific surface area CBC was prepared from corn bob by high-temperature carbonization with CO2 physical activation or KOH chemical activation. The maximum specific surface area and the minimum resistivity of CBC activated by KOH were2141 m2/g and 0.285 Ω· cm, respectively while by CO2 were 753 m2/g and 0.545 Ω· cm, respectively.(2) The influence factors of toluene adsorption by CBC were investigated. The adsorption mass transfer area was mainly affected by the inlet concentration of toluene. The toluene adsorption capacity of CBC activated by KOH was 559 mg/g, and that by CO2 was about 157 mg/g. The toluene adsorption capacity kept constant when CO2-activated CBC was shaped into a cylinder, but the adsorption mass transfer rate reduced.(3) The activation energy of toluene desorption of CBC was evaluated by the multi-heating rate method, about 59.8 kJ/mol. The desorption experiments was carried out with various operating temperatures and different thicknesses, as well as shaped CBC. The maximum desorption rate of shaped CBC were more than 50% higher than the 0.7g powder sample under the same temperature.(4) Experiments were carried out to study the processes of desorption and degradation of toluene absorbed on CBC with a fluidized bed discharge mode and a dielectric barrier discharge mode. Most of the toluene absorbed on CBC was desorbed within the first ten minutes. The degradation rate and the total degradation rate reached 68% and 55.8%, respectively with a residence time of 0.19s and a discharge time of 16min. To increase oxygen content would effectively facilitate degradation and reduce tar formation.