Fly ash consists of various metal oxides which can remove SO2 gas by the catalyst effect. When fly ash is added in the preparation process of pitch-based activated carbon, the pitch particles aggregate and fly ash is embedded in the activated carbon. To increase SO2 gas removal performance, activated carbon was prepared by surface-treated fly ash and petroleum-based pitch. Carboxyl groups were introduced into the fly ash by malic acid treatment. The introduced carboxyl groups acted as an activation agent to create micropore around the fly ash, and created micropores were exposed to the fly ash outside of the activated carbon. The exposed fly ash increased removal amount of SO2 gas by a catalytic effect of the metal oxides. The SO2 gas removal performance improved by 34% because of the catalyst effect of the exposed fly ash and improvement in the micropore structure in the activated carbon.

    Abstract
    1 Introduction
    2 Experimental
        2.1 Materials
        2.2 Malic acid treatment of fly ash
        2.3 Preparation of activated carbon with fly ash
        2.4 SO2 gas adsorption properties
    3 Results and discussion
        3.1 Surface properties of malic acid-treated fly ash
        3.2 Pore structure properties of prepared activated carbon
        3.3 SO2 gas adsorption properties of prepared activated carbon
    4 Conclusions
    Acknowledgements 
    References

• Min Il Kim(Carbon Industry Frontier Research Center, Korea Research Institute of Chemical Technology (KRICT))
• Ji Sun Im(Carbon Industry Frontier Research Center, Korea Research Institute of Chemical Technology (KRICT), Advanced Materials and Chemical Engineering, University of Science and Technology (UST))
• Sang Wan Seo(Carbon Industry Frontier Research Center, Korea Research Institute of Chemical Technology (KRICT), Department of Chemical Engineering and Applied Chemistry, Chungnam National University)
• Jong Hoon Cho(Carbon Industry Frontier Research Center, Korea Research Institute of Chemical Technology (KRICT), Department of Chemical Engineering and Applied Chemistry, Chungnam National University)
• Young‑Seak Lee(Department of Chemical Engineering and Applied Chemistry, Chungnam National University)
• Sangjin Kim(Gyeongbuk Science and Technology Promotion Center, Gumi Electronics and Information Technology Research Institute (GERI))