Study On Preparation Of Porous Carbon And Adsorption Of CO₂

Since the industrial revolution, with human industrial activity increased gradually, the greenhouse effect which leads to a series of influence such as global warming and rising of sea level has become the most serious environmental problem. Greenhouse effect is mainly attributed to the excessive emission of greenhouse gas which major constituent is CO2. The increase of CO2concentration in atmosphere is mainly due to the abuse of fossil fuels. By the way, CO2is also an important source that can be used in many fields such as industry, food, medicine, firefighting, etc. So the CO2capture and storage technology has become a hot issue.In this paper, three series of porous carbon which contains different physical characteristics and surface chemistry were prepared. The pore structure, surface chemistry and CO2adsorption ability of these carbons were studied to research the adsorption mechanism. Firstly, a series of N-doped activated carbons was prepared from bean dregs by KOH activation and then its physics characteristics, surface chemistry and CO2adsorption property were tested. The CO2adsorption capacity of SK carbons can reach as high as4.24mmol·g-1at25℃under1atm. It is found that the CO2adsorption property of SK is not closely associated with carbons’surface area and pore structure, but related to the surface nitrogen content. Quantum chemical calculation and FT-IR measurements reveal that the introduction of N into carbon surface facilitates the hydrogen-bonding interactions between carbon surface and CO2molecules, which accounts for the superior CO2uptake on the activated carbon. In order to study the effect of pore structure on CO2adsorption ability, a series of TiC-CDC carbons with different pore diameter was prepared by Cl2sculpting method. It is found that pores smaller than8nm contribute the most to the CO2uptake. At last TiC-CDC-700was oxidized with nitric acid at different temperature to research the effect of CDC carbons’oxidation degree on CO2uptake ability. It is found that the oxidation degree of CDC carbons is also greatly influence the CO2adsorption property of CDC carbons.