This study evaluated how acid treatment affects the ability of customized beads of activated carbon (BAC) to remove formaldehyde from air. Two different acids (hydrofluoric acid and sulfuric acid) were used to modify the surface of BAC prepared from a polymer material. The acid-modified BACs were further subjected to heat treatment. Physical and chemical characteristics of modified and unmodified BACs were investigated using nitrogen adsorption, Fourier transform infrared spectroscopy, Raman spectroscopy, X-ray fluorescence, and X-ray photoelectron spectroscopy. Formaldehyde removal was evaluated under both dry and moist conditions. From the results, acid treatment clearly improved the adsorption performance, especially under the moist condition. Qualitative and quantitative surface analyses were conducted, mainly to examine the amount of O-bonds after acid treatment and the formation of S–O or Cl–O on BAC.

    Abstract
    1 Introduction
    2 Experimental
        2.1 Materials and sample preparation
        2.2 Methods
    3 Results and discussion
        3.1 Characterization of BAC
        3.2 HCHO adsorption
        3.3 Effect of thermal regeneration on HCHO adsorption
    4 Conclusions
    Acknowledgement 
    References

• Yu‑Jin Kang(Department of Chemical and Biological Engineering, Hanbat National University)
• Hyung‑Kun Jo(Department of Chemical and Biological Engineering, Hanbat National University)
• Min‑Hyeok Jang(Department of Chemical and Biological Engineering, Hanbat National University)
• Gyoung‑Jae Han(Department of Chemical and Biological Engineering, Hanbat National University)
• Seong‑Jin Yoon(Department of Chemical and Biological Engineering, Hanbat National University)
• Kyeongseok Oh(Department of Chemical and Biological Engineering, Inha Technical College)
• Joo‑Il Park(Department of Chemical and Biological Engineering, Hanbat National University)