Study On Preparation And Modification Of Activated Carbons From Corncob And Their Adsorption Performance For CO₂

Due to the acceleration of modern industrialization, global excessive burning fossil fuel emissions a large amount of carbon dioxide and other gases into the atmosphere, causing global warmer year by year. Therefore, carbon dioxide capture recovery technology for reducing carbon dioxide emissions has important significance, and the research of high performance, cheap, environmental protection adsorption materials became imminent topic around the world. Activated carbon was widely used due to its high specific surface, adsorption ability, high mechanical strength, good chemical stability, easy regeneration. And there were high economic benefits and broad prospects for development in the preparation of activated carbon with the crop waste. This paper studies the preparation of activated carbons with corncob and their modification, successfully used for recycling capture carbon dioxide.First of all, this thesis using corncob as raw materials by KOH chemical activation method prepared of activated carbon in two steps, after carbonization of the grinding corncob to high temperature activation with KOH as activator. By the basis of a large number of experiments, this paper analyzed the factors such as time, temperature, concentration of material on the preparation of activated carbon and then determined that the best preparation conditions of activated carbon from corncob which can be used in CO2gas capture.The best preparation condition of activated carbon from corncob was:the carbonization temperature,450℃; the coke time,4h; KOH solution concentration,1mol/L; the activation temperature,800℃. On this condition, the specific surface area of activated carbon was the largest,653.2m2/g, and it has pore structure and abundant organic functional groups at the same time. This paper used the thermogravimetric analyzer to identified that the adsorption quantity of CO2was1.649mmol/g and the adsorption quantity of N2was0.418mmol/g. This paper shows that the activated carbon from corncob has the good adsorption performance for CO2gas and it can be used in CO2gas capture. Then, this thesis modified the activated carbon from corncob with HNO3, Ca(NO3)2, NaNO3, Mg(NO3)2and Na2CO3, K2CO3, NH3·H2O and used the X ray fluorescence analysis, the Fourier transform infrared spectrum analysis, sorption isotherm analysis, and other analysis methods to research the effects of activated carbon performance. The results shows that the CO2gas adsorption of the activated carbon from corncob after Na2CO3modified was up, and the number was2.043mmol/L under35℃,28.5%higher than before. So, the activated carbon from corncob after Na2CO3modification can improve the CO2gas adsorption performance, better recycling capture CO2gas.