Preparation Of Activated Carbon Based On CO₂ Removal From Distiller’s Grains

With the continuous improvement of the call for carbon neutrality in China,the existing CO₂emission problem in China also needs to be solved urgently.At present,the most effective method to reduce CO₂is carbon capture and storage（CCS）technology.Activated carbon,as a widely used adsorption material,provides an effective method for CO₂capture.Distiller’s grains as waste,rich in lignin and cellulose,is a very suitable raw material for the preparation of activated carbon.Therefore,using distillers’grains as raw material not only realizes the policy of energy saving and emission reduction,but also realizes the high value utilization of solid waste.Based on this,in this paper,the carbonized porous materials of distiller’s grains were used as raw materials.Based on the mechanism of activation reaction,the effects of activation temperature and alkali-carbon ratio on the pore structure were revealed,and the optimal process route for the preparation of distiller’s grains based activated carbon was determined.The CO₂adsorption performance of activated carbon based on distiller’s grains was analyzed,and its adsorption mechanism was explored by adsorption heat and low pressure adsorption model.Specific research results are as follows:（1）Distile-based activated carbon was prepared by carbonization and KOH activation process.Under the conditions of carbonization temperature of 450℃,mass ratio of KOH to raw material of 3:1,activation temperature of 850℃and activation time of 60min,the prepared activated carbon had developed pore structure,and its specific surface area and pore volume were 2225m²/g,respectively.The micropore volume is 1.0656cm³/g,and most of the micropore sizes are between 0.5 nm and 0.9nm.The results show that high activation temperature and alkali/carbon ratio can promote the development of mesoporous and macroporous activated carbon,but are not conducive to the growth of micropores and the increase of specific surface area.（2）The CO₂adsorption performance of the prepared distiller’s grains based activated carbon was measured.The test results showed that the maximum adsorption capacity of activated carbon with a specific surface area of 2122m²/g was 3.72mmol/g at 25℃and1bar.The adsorption capacity of CO₂increased with the increase of micropore volume,and the micropores at 0.8～1nm were more favorable to CO₂adsorption.The experiment showed that the CO₂adsorption capacity of activated carbon from lees decreased with the increase of temperature.The calculation of adsorption model and adsorption heat showed that the CO₂adsorption heat of activated carbon was 18.3k J/mol on average,which was a typical physical adsorption process and a monolayer adsorption.The degradation of activated carbon was 18.06%,indicating that activated carbon from distiller’s grains had better regeneration performance.