Study on Regeneration of Activated Carbon Fiber with Toluene by Microwave Radiation

Abstract: Adsorption is the most applied method to control the emission of volatile organic compounds (VOCs).Activated carbon fiber (ACF) is a great active adsorbent and environmental engineering material and show greater capability than traditional activated carbon, being recognized and studied more and more as an adsorbent. Adsorbent regeneration decide the economical capacity of the adsorption system and is important as same as adsorption.The study of regeneration of ACF applied to control air pollution is less than the ACF applied to control waste water pollution.Microwave radiation regeneration is a new technology for adsorbent regeneration.In this paper we select toluene as representation of organic exhaust gas and regenerate ACF adsorbing toluene by microwave radiation.The present work studied the adsorption of low concentration VOC such as toluene onto viscose rayon based ACF. Toluene adsorption isotherms were determined at the temperature of 20℃, Langmuir equation and Freundlich equation were used to fit the measured adsorption data.The test results showed that the ACF have large adsorption capacity for low concentration VOCs, Langmuir equation and Freundlich equation can fit the measured adsorption data greatly and Freundlich equation was better.A suit of experimental device was designed.In the process of microwave regeneration, K-armoured thermocouple can be used to determine temperature of ACF in microwave field, microwave power and linear speed of carrier gas influence the temperature of the ACF greatly and quantity of ACF also has large relation to the temperature.From regeneration rate curve and regeneration kinetics,the results show that microwave regeneration rate is very high and regeneration is very quick. Regeneration rate can reach 97% or higher in 3min~4min when microwave power is higher than 420W. By orthogonal experiment,the connection between ratio of regeneration and influencing factors:rmicrowave powe、 regeneration time、speed of carrier gas> quantity of ACF and adsorption capacity of ACF are studied.Optimized conditions of regeneration were summarized. The condition is that microwave power is 700Wn regeneration time is 210s ^ speed of carrier gas is 0.2m/s> quantity of ACF is 235mg and adsorption capacity of ACF is 550.38mg/g.It was found that regeneration times has no distinct influence on adsorption the performance of regenerated ACF.Microwave regeneration requires less energy and shorter time than conventional regeneration methods;the equipment is simple;regeneration rate is high and the losing of ACF is little.So, the method of microwave regeneration will be applied more to control the emissions of air pollutants…
Key words: ACF; microwave radiation; regeneration; toluene

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