Preparation Of Phenolic Activated Carbon Fiber Activated By ZnCl₂ And Their VOCs And CO₂ Adsorption Performance

In recent years,a volatile organic pollutant?VOCs?has attracted wide attention in the field of environmental science,and is recognized as one of the pollutants with considerable environmental and human health hazards.At the same time,the burning of fossil fuels for more than a century in the industrial process has also released a large amount of CO₂.Previous scholars have carried out a large number of exploratory experiments to prepare environmentally friendly adsorption materials for the removal of VOCs and CO₂.Among them,activated carbon fiber?ACF?has attracted much attention because of its stable properties,low cost and easy availability.However,the pore size distribution of traditional activated carbon fiber is relatively broad,so it is difficult to achieve specific adsorption for a certain gas.In view of the shortcomings of the above activated carbon fibers,this paper uses specific activation methods to modify the surface of activated carbon fibers,regulate its pore size distribution,improve the adsorption capacity of activated carbon fibers,enhance the adsorption capacity of activated carbon fibers for specific VOCs and CO₂,and further explore its adsorption mechanism.The main contents and results of this paper are as follows.?1?Phenolic fiber was used as carbon source and ZnCl₂ as activator to prepare activated carbon fiber.A series of characterization tests showed that the obtained activated carbon fiber showed amorphous carbon structure of non-woven fabric,rich pore structure and no special functional groups on the fiber surface,which was beneficial to the physical adsorption process.The isothermal adsorption and desorption tests of N₂ and CO₂ showed that the addition of ZnCl₂ activator significantly affected the pore distribution of the final activated carbon fiber.By exploring the pore size distribution map of the sample,we found that the micro/mesopore of the sample is mainly distributed in the range of 1.0-1.4 nm,1.5-2.0 nm and 2.0-5.0 nm.?2?Adsorption of toluene,ethyl acetate and CO₂,by in-situ adsorption and in-situ on-line determination of adsorption capacity of the samples by gas chromatography.Combined with the data of adsorption and pore size distribution,the results show that the micropore of 1.0-1.4nm on activated carbon fiber is beneficial to the adsorption of CO₂,while the adsorption amount of toluene and ethyl acetate in the range of 1.5-2.0 nm is the greatest.The adsorption kinetics of toluene on activated carbon fiber was studied.The results show that the adsorption process of toluene is closer to the multi-layer adsorption,and it is mainly physical adsorption process.The adsorption and separation experiments of CO₂/N₂ were carried out,and according to the adsorption theory of ideal solution,it was found that activated carbon fiber had high CO₂/N₂ selectivity.According to the calculation of Clausius-Clapeyron equation,it is concluded that the adsorption process of CO₂ by activated carbon fiber is a physical adsorption exothermic process.