Study On Treatment Of Printing Waste Gas By Microwave Activated Carbon Fiber

There is large amounts of ethanol in the volatile organic gases of the printing industry, which comes from the volatilization of organic solvent. Comparing with volatile organic gases, the gases in printing industry causes less harmful. But it is a waste of resource when they are released in the air. Activated carbon fiber has good adsorptive property, which could effectively recycle the ethanol in printing waste gas. It not only reduces the waste of resources, but also reduces the cost of enterprise.In this article, through the comparison of the adsorptive property of different kinds of activated carbon fiber, the activated carbon fiber that produces by Jiangsu sutong carbon fiber factory was choose in this experiment. The flow chat of the adsorption of ethanol on activated carbon fiber was designed. Through the single factor experiment, the optimum conditions were determined:the air flow rate was 1.5L/min, the dosage of activated carbon fiber was 2.0g, the adsorption temperature is room temperature and the adsorption pressure is 0.08MPa. And the adsorption quantity of activated carbon fiber was up to 398.4mg/g. When the activated carbon fiber or ethanol gas contained water, the adsorption was significantly decreased. So activated carbon fiber should be kept dry in the whole process.Through the study on microwave desorption of ethanol-loaded activated carbon fiber under N2 condition, we can draw the following conclusions. The optimum conditions were determined through the single factor and orthogonal experiments: the microwave power was 800W, the irradiation time was 180s, the dosage of activated carbon fiber was 2.5000g and the nitrogen flow rate was 1.2L/h. The rate of desorption was 93.4% and the exports ethanol concentration was 95.4% under optimum conditions.This paper combines vacuum technology with microwave-desorption technology, and microwave desorption under vacuum condition realizes fine separation effect. Compared with the desorption in nitrogen atmosphere, the desorption effect was better and the rate of mass loss was smaller under vacuum condition. The optimum condition was:the vacuum degree was 0.05MPa, the irradiation time was 300s, the dosage of activated carbon fiber was 4.0000g and the microwave power was 680W. The rate of desorption was 97.1% and the exports ethanol concentration was 97.5%. The adsorption of activated carbon fiber after microwave regeneration for many times was larger than the fresh activated carbon fiber.The activated carbon fiber was modified by K2SO4 and Na2SO4, and the influence factors on the modification on the activated carbon fiber such as impregnation concentration, dipping time, carbonization temperature and carbonization time were discussed. The results were shown that the adsorptive property modified by K2SO4 was better. The adsorption of modified activated carbon fiber was 554.7mg/g, which was soaked in 1.5% K2SO4 solution for 4h and carbide at 700℃ for 60min. The surface morphology and surface chemical structure of modified activated carbon fiber were analyzed by SEM, XRD and FTIR. The number of functional groups decreased that lead to the increase of the pore. The surface of activated carbon fiber became rough through the modification process. And the pore structure also changed. These phenomena were important to the adsorption of ethanol on activated carbon fiber.