Wang Jie, Adelodun Adedeji Adebukola, Oh Jong Min, Jo Young Min
Department of Applied Environmental Science, Kyung Hee University, 1732, Deogyeong-daero, Giheung-gu, Yogin-si, Gyeonggi-do, 17103, Republic of Korea.
Centre for Renewable Energy Technology (CRET), The Federal University of Technology, P.M.B. 704, Akure, Nigeria.
Nano Converg. 2020 Feb 17;7(1):7. doi: 10.1186/s40580-020-0217-y.
The CO adsorption selectivity of plain activated carbon nanofibers (ANF) is generally low. For enhancement, nitrogen functionalities favorable for CO adsorption are usually tethered to the ANF. In the current study, we adopted chemical impregnation using 0.5 wt% tetraethylenepentamine (TEPA) solution as an impregnant. To enhance the impregnation of TEPA further, preliminary oxidation of the nanofibers with 70% HNO was conducted. The effects of HNO and TEPA treatments on the modified ANFs were investigated for physical (using N monosorb, thermogravimetric analyzer, scanning electron microscopy) and chemical (X-ray photoelectron spectrometer) changes. From the results, we found that although TEPA impregnation reduced the specific surface area and pore volume of the ANFs (from 673.7 and 15.61 to 278.8 m/g and 0.284 cm/g, respectively), whereas the HNO pre-oxidation increased the number of carboxylic groups on the ANF. Upon TEPA loading, pyridinic nitrogen was tethered and further enhanced by pre-oxidation. The surface treatment cumulatively increased the amine content from 5.81% to 13.31%. Consequently, the final adsorption capacity for low (0.3%) and pure CO levels were enhanced from 0.20 and 1.89 to 0.33 and 2.96 mmol/g, respectively. Hence, the two-step pre-oxidation and TEPA treatments were efficient for improved CO affinity.
普通活性炭纳米纤维（ANF）对CO的吸附选择性通常较低。为了提高吸附选择性，通常将有利于CO吸附的氮官能团连接到ANF上。在本研究中，我们采用0.5 wt%四乙烯五胺（TEPA）溶液作为浸渍剂进行化学浸渍。为了进一步提高TEPA的浸渍效果，先用70%的HNO对纳米纤维进行了初步氧化。通过物理方法（使用N单吸附仪、热重分析仪、扫描电子显微镜）和化学方法（X射线光电子能谱仪）研究了HNO和TEPA处理对改性ANF的影响。结果表明，虽然TEPA浸渍降低了ANF的比表面积和孔体积（分别从673.7和15.61降至278.8 m²/g和0.284 cm³/g），但HNO预氧化增加了ANF上羧基的数量。负载TEPA后，吡啶型氮被连接上，并且通过预氧化进一步增加。表面处理使胺含量从5.81%累积增加到13.31%。因此，对于低浓度（0.3%）和纯CO水平，最终吸附容量分别从0.20和1.89提高到0.33和2.96 mmol/g。因此，两步预氧化和TEPA处理对于提高CO亲和力是有效的。
