Development of ion-exchange properties of bamboo charcoal modified with concentrated nitric acid

3rd International Conference on Water Resource and Environment

地球科学;生态环境科学

Khandaker, S.^1 ; Kuba, T.^1 ; Toyohara, Y.^1 ; Kamida, S.^1 ; Uchikawa, Y.^1

Department of Urban and Environmental Engineering, Graduate School of Engineering, Kyushu University, 744 Motooka, Nishi-ku, Fukuoka

819-0395, Japan^1

关键词: Acidic functional groups;    Concentrated nitric acid;    Field emission scanning;    Ion exchange properties;    Nitrogen adsorption isotherm;    Point of zero charge;    Porous properties;    Surface functional groups;   

Others  :  https://iopscience.iop.org/article/10.1088/1755-1315/82/1/012002/pdf
DOI  :  10.1088/1755-1315/82/1/012002

学科分类：环境科学（综合）

来源: IOP

【 摘 要 】

The surface chemistry and the structural properties of activated carbon can be altered by the acidic modification. The objective of this study is to investigate the changes occurring in bamboo charcoal (BC) during activation with concentrated nitric acid. Low temperature (500°C) carbonized BC has been prepared and oxidized with 70% concentrated boiling nitric acid (BC-AC). The porous properties of the BC are analyzed with nitrogen adsorption isotherm at 77 K. The surface structure is observed by Field emission scanning electronic microscope (FESEM) and the surface functional groups are examined by Fourier transform infrared (FTIR) spectroscopy, X-ray photoelectron spectroscopy (XPS) and the pH of the point of zero charge (pHPZC). The results reveal that severe oxidation with HNO3considerably decreases the surface area of BC with enhanced pore widening and FESEM observation demonstrates the erosive effect of oxidation. The FTIR analysis detects that some absorption bands are assigned for carboxyl, aldehyde and ketone groups on BC-AC. The XPS analysis also clearly shows that the ratio of oxygen and acidic functional groups has been enriched significantly on the BC-AC. The low pHPZCvalue of BC-AC confirms that the surface is highly acidic for the fixation of acidic functional groups on surface. In general, the existence of the abundant amount of acidic functional groups on adsorbents enhances the sorption of heavy metals ions in aqueous solution. Therefore, it is strongly expected that the modified BC, activated under the proposed conditions would be a promising ion exchanger in aqueous solution and can be applied for the adsorption of different heavy metal ions and radioactive materials from effluent.