Effect Of Amino-Controlled Chitosan-Based Activated Carbon On CO₂ Adsorption Performance

The CO₂ produced by the burning of fossil fuels is one of the main greenhouse gases causing the greenhouse effect,leading to a series of disasters such as global warming,which seriously endangers the survival and life of human beings.Therefore,various carbon capture technologies have been proposed.Among them,the adsorption method has a certain application prospect because of its mild operating conditions,relatively low corrosivity and low energy consumption for regeneration.At the same time,having proper pore structure and amino functional group is an effective means to improve carbon capture efficiency.In this paper,chitosan-based activated carbon was prepared by using chitosan as precursor,and different organic amine solution diethylenetriamine?DETA?was used.Tetraethylenepentamine?TEPA?is a surface modifier which is impregnated and modified to prepare a new type of adsorbent material,and its adsorption performance on CO₂ is studied.The adsorbent materials were characterized by thermogravimetric analysis,physical adsorption?BET?,scanning electron microscopy?SEM?,X-ray diffraction?XRD?,and organic element analyzer.The thermal stability analysis showed that the aminated adsorbent did not decompose below 120?,and the thermal stability was good.The BET analysis results show that the chitosan-based activated carbon has micro-mesotrope properties,and the pore volume and specific surface area of the aminated adsorbent material are reduced to some extent.The SEM results show that the samples have a rich pore structure,and the filler is clearly seen on the surface and pores of the aminated adsorbent.The results of XRD analysis show that the chitosan-based activated carbon has certain graphite phase characteristics,and the aminated adsorbent material can still maintain the original carbon skeleton structure.The results of elemental analysis showed that the content of nitrogen element in the aminated treatment increased,indicating that the amino functional group was successfully loaded onto the surface of chitosan-based activated carbon.The aminated chitosan-based activated carbon improved the CO₂ adsorption capacity,and the CAC-TEPA overall effect was better than that of the CAC-DETA modification.The other conditions were the same,and the maximum adsorption amount of both was 30?,and unmodified.The adsorption effect of the adsorbent on the CO₂ was increased by 50%and 39%,respectively.The amount of CO₂ adsorbed by the aminated adsorbent material is not positively correlated with the amount of impregnation of the amine.As the amount of impregnation increases,the amount of CO₂ adsorbed increases first and then decreases,that is,there is an optimal ratio.The regeneration performance of CAC-TEPA samples with a mass ratio of 5:2 was studied.Although the adsorbent adsorption amount decreased to some extent,it still maintained good adsorption performance.Under the pure CO₂ gas flow,the adsorption rate of the aminated adsorbent is faster and the adsorption amount is increased.The CAC-TEPA sample had better CO₂ adsorption effect under water conditions than anhydrous conditions,and the CO₂ adsorption amount increased by28.1%.