| If the volatile organic gas produced in industrial production is discharged directly to the environment,it will bring a serious threat to the environment and human health.The regeneration process-and properties of activated carbon fiber adsorption-microwave irradiation treatment of organic volatile gas containing ethanol and toluene are explored in this paper under normal temperature and pressure.In this paper,ethanol and toluene are used as the research objects,the activated carbon fiber was used as the adsorbent and microwave irradiation was used as energy of desorption.it was showed by the research that the activated carbon fiber as adsorbent has high adsorption capacity of ethanol and toluene,the higher desorption effect of microwave irradiation on the adsorption of toluene and ethanol loaded on activated carbon fiber,activated carbon fiber regeneration could be achieved in a relatively short period of time,and also energy be saved effectively,resources be recycled and air pollution has be effectively controlled.It was showed by experiments that the saturated adsorption of ethanol was 373 mg/g and breakthrough time about 15 min and saturated adsorption of toluene was 465 mg/g,the breakthrough time about 50 min,under the experimental conditions of that 25? of temperature,atmospheric pressure and 40 L/h of gas volume.In addition,due to the activated carbon fiber had a stronger adsorption capacity of toluene and the competitive adsorption,toluene which was more harmful toenvironment could be removed completely in waste gas containing toluene and ethanol.Three kinds of adsorption kinetic model,the quasi-first order adsorption kinetics model,the quasi-second order adsorption kinetics model and the intraparticle diffusion were used to simulate static adsorption of ethanol and toluene.It was showed by the experiments that adsorption on activated carbon fiber with different concentrations ethanol or toluene could be simulated by the pseudo first order kinetic curves.At a temperature of 25 ? and normal pressure,for 3 different initial concentrations of ethanol,the fitting degree and fitting models were as follows,the initial concentration of ethanol is about 16.4 g/m3,the pseudo-first order adsorption kinetic curve fitting was 0.996 and the fitting curve equation is ln?qe-q?=-0.1093t + 4.5357;the initial concentration 98.6 g/m3,the pseudo-first order adsorption kinetics of linear goodness of fit 0.986 and the fitting curve equation was ln?qe-q?=-0.0795t + 4.6870;the initial concentration 295.9 g/m3,the quasi-first order adsorption kinetic linear degree about 0.991 and the fitting curve equation was ln?qe-q?=-0.0687t + 5.9786.At a temperature of 25 ? and normal pressure,for 3 different initial concentrations of toluene,the fitting degree and fitting models were as follows,the initial concentration of toluene was about 18.1 g/m3,the pseudo-first order adsorption kinetic curve fitting was 0.994 and the fitting curve equation was ln?qe-q?=-0.0728t + 5.1068;the initial concentration 108.4 g/m3,the pseudo-first order adsorption kinetics of linear goodness of fit 0.993 and the fitting curve equation was ln?qe-q?=-0.2622t + 5.7597;the initial concentration 325.1 g/m3,the pseudo-first order adsorption kinetic linear degree about 0.986 and the fitting curve equation was ln?qe-q?=-0.5520t + 6.4780.The single factor experiment and orthogonal test were used to test effects of activated carbon fiber,power of microwave,irradiation time of microwave,velocity of carrier gas and packing density of activated carbon fiber on the microwave desorption of ethanol loaded on activated carbon fiber.It was concluded that the best conditions of desorption were 528 W of microwave power,80 s of irradiation time,16 L/h of the nitrogen flow rate,0.085 g/cm3 of the activated carbon fiber packing density and showed that the average desorption of ethanol loaded activated carbon fiber was 99.52%and the average loss rate of activated carbon fiber was 1.19%.Under the optimal conditions and the 10 times desorption,adsorption value of ethanol was maintained at between 375 mg/g and 385 mg/g,activated carbon fiber adsorption performance was stable and good shape,but ashing phenomenon occurred with the regeneration.The single factor experiment and orthogonal test were used to test effects of activated carbon fiber,power of microwave,irradiation time of microwave,velocity of carrier gas and packing density of activated carbon fiber on the microwave desorption of toluene loaded on activated carbon fiber.It was concluded that the best conditions of desorption were 290 W of microwave power,120 s of irradiation time,48 L/h of the nitrogen flow rate,0.094 g/cm3 of the activated carbon fiber packing density and showed that the average desorption of toluene loaded activated carbon fiber was 95.59%.Under the optimal conditions and 10 times after desorption,adsorption value of toluene on activated carbon fiber increases by about 35 mg/g.Light ashing phenomenon of activated carbon fiber appears and activated carbon fiber was easy to fracture after repeated regeneration.SnO2 was used as flame retardant supported to load on activated carbon fiber,which significantly reduces the thermal oxidation of toluene by microwave desorption of activated carbon fiber.It was showed by gas chromatography analysis that the content of toluene in the recovery liquid increased from 97.95%to 99.40%. |
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