TY - JOUR
T1 - Maximizing the number of oxygen-containing functional groups on activated carbon by using ammonium persulfate and improving the temperature-programmed desorption characterization of carbon surface chemistry
AU - Li, Na
AU - Ma, Xiaoliang
AU - Zha, Qingfang
AU - Kim, Kyungsoo
AU - Chen, Yongsheng
AU - Song, Chunshan
N1 - Funding Information:
This work was partially supported by the US Department of Energy through CPCPC Grant No: DE-FC26-03NT41874 , Subcontract No: 3551-TPSU-DOE-1874 . The China Scholarship Council is gratefully acknowledged for a scholarship to support Na Li at the Pennsylvania State University for this study. The authors would also like to thank Dr. Jian Zhu for helpful discussion.
PY - 2011/12
Y1 - 2011/12
N2 - The number of oxygen-containing functional groups (OCFGs) on the surface of a commercial activated carbon (AC) was maximized using ammonium persulfate ( (NH4)2S2O8, APS) as an oxidant. Effects of the oxidation conditions, including temperature, time and concentration of APS, on physical and chemical properties of the treated AC were examined to develop a relationship between the oxidation conditions and surface chemistry of AC. A maximum amount of oxygen, 18.7 mmol/g, on the AC was achieved by oxidation with 2.0 mol/L APS solution and an APS/AC weight ratio of 9.1 at 60 ° C for 3 h. Temperature-programmed desorption coupled with mass spectrometry (TPD-MS) was used to identify and quantify OCFGs on the AC samples. It was found that using the TPD-MS method currently reported in the literature to quantify various OCFGs on the carbon surface on the basis of TPD-CO 2 and TPD-CO profiles may significantly underestimate the number of carboxyl groups, and overestimate anhydrides and lactones due to some in situ reactions of OCFGs during the TPD-MS analysis. The amount of H2O and CO released in the temperature range corresponding to decomposition of carboxyl groups should be taken into account when estimating the amount of carboxyl groups on AC.
AB - The number of oxygen-containing functional groups (OCFGs) on the surface of a commercial activated carbon (AC) was maximized using ammonium persulfate ( (NH4)2S2O8, APS) as an oxidant. Effects of the oxidation conditions, including temperature, time and concentration of APS, on physical and chemical properties of the treated AC were examined to develop a relationship between the oxidation conditions and surface chemistry of AC. A maximum amount of oxygen, 18.7 mmol/g, on the AC was achieved by oxidation with 2.0 mol/L APS solution and an APS/AC weight ratio of 9.1 at 60 ° C for 3 h. Temperature-programmed desorption coupled with mass spectrometry (TPD-MS) was used to identify and quantify OCFGs on the AC samples. It was found that using the TPD-MS method currently reported in the literature to quantify various OCFGs on the carbon surface on the basis of TPD-CO 2 and TPD-CO profiles may significantly underestimate the number of carboxyl groups, and overestimate anhydrides and lactones due to some in situ reactions of OCFGs during the TPD-MS analysis. The amount of H2O and CO released in the temperature range corresponding to decomposition of carboxyl groups should be taken into account when estimating the amount of carboxyl groups on AC.
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U2 - 10.1016/j.carbon.2011.07.015
DO - 10.1016/j.carbon.2011.07.015
M3 - Article
AN - SCOPUS:84857033737
SN - 0008-6223
VL - 49
SP - 5002
EP - 5013
JO - Carbon
JF - Carbon
IS - 15
ER -