Preparation Of Activated Carbon Fiber And The Adsorption Of Origanic Compounds Vapor On Activated Carbon Fiber

With widely application of volatility organic compound(VOC) in industry, more and more organic pollutants is released to air. Most of them have low boiling points which will not only pollute the air but also be harmful to the health of human being. For the effect and economic interest, activated carbon fiber(ACF),which has high special surface area and abundant, narrow distributing micropore, becomes more and more important. Now, the key of technique is how to improve VOC adsorption capability of ACF and the efficiency of the material in the treatment of VOC. The relationship of preparation technics and the structure of products were discussed in this work by adjusting the technics of preparation of ACFs.1. Effect of activated condition on pore structure and adsorption capacities of ACF for VOC was studied in this work. Using CO₂ and KOH as activated agent, a series of viscose-based activated carbon fibers (VACF) have prepared at different temperature and different time. The properties of N₂ adsorption, the BET surface area, the pore size distribution and the pore volumes of ACFs were characterized by means of BET analysis. The equilibrium adsorption amounts of organic compounds vapor were measured by gravimetric methods using a Cahn-2000 electrobalance. The result shows that yield of ACF decreases with the elevation of activation degree, and micropore volume and special surface area of ACF increase with its activation degree. Some mesopore will develop at high activation degree. In appropriate activation condition, the special surface area of ACF can reach upon 1900m²/g(CO₂) and 2325 m²/g(KOH). Experimental results show that adsorption amount of ACF for benzene increase with the drop of ACF. When activation degree keeps increasing, micropore of ACF was enlarged, which leads to the decrease of adsorbability of ACF for VOC, and the adsorption amount of VOC would accordingly decrease.2. Calculation of adsorption heat and relations between of adsorption heat and adsorption capacities of ACF. Adsorption isotherms of benzene on activated carbon fiber were studied in this paper. The equilibrium adsorption amounts of benzene under 298K～328K and 0～1.995KPa were measured by gravimetric methods using a Cahn-2000 electrobalance. Experiment data were simulated by Langmuir equation commendably. Isometric heat of adsorption of benzene was calculated using Clausius-Clapeyron equation according to adsorption isotherms. It was proved that isometric heat of adsorption of benzene decreased with the increase of adsorption amount. The average heat of adsorption of benzene was 39.79KJ/mol calculated using Vant Hoff equation.3. The adsorption of benzene in Activated Carbon Fibers was studied in this work. The results prove that, the adsorption capacity of benzene and alkyl in ACF was 378.4mg/g and 140mg/g. The difference of adsorption qulity was affected by the configuration of moleculars.