一种氮杂化多孔炭材料的制备表征及其对染料的吸附性能研究

Preparation,Characterization,Dye Adsorption of a Novel N-doped Porous Carbon

选用玉米秸秆为原料,氨气为活化剂,制备一种新型氮杂化多孔炭质吸附材料。利用比表面积测定仪、X射线光电子能谱仪、拉曼光谱和傅里叶红外光谱等技术,较系统地研究了该氮杂化炭材料的理化特性,并以常见染料酸性橙7为代表,探讨了其对染料的吸附性能。结果表明:当活化温度从600℃提高到800℃时,材料表面氮元素含量从3.2%增加到8.81%,比表面积从72.7 m^2·g^(-1)增加到418.7 m^2·g^(-1),微孔率从16.2%增加到71.5%;同时,其对酸性橙7的吸附效率和吸附容量也显著提高,最大吸附量可达292 mg·g^(-1),优于常见的炭质吸附材料;等温吸附曲线符合Freundlich方程,为异质性表面的多层吸附过程,吸附机理主要以化学吸附为主。该氮杂化炭材料比表面积大、微孔结构发达、吸附能力强,具有较广阔的应用前景。

A novel N-doped porous carbon was produced from corn stalks with NH3 gas as activator. Its characterization was investigated using N2 adsorption/desorption , X- ray photoelectron spectroscopy(XPS), Raman spectroscopy , and Fourier transform infrared spec-troscopy(FTIR). Its adsorption of acid orange 7(AO7, as a model dye)was also examined.Results showed that increasing annealing temper-ature from 600℃to 800℃increased N content in the porous carbon from 3.2%to 8.81%, BET surface area from 72.7 m2·g-1 to 418.7 m2· g-1, and microporosity degree(ratio of V m/V t)from 16.0%to 71.5%. This porous carbon exhibited high dye adsorption capacity, with AO7 adsorption up to 292 mg·g-1, greater than that of many common carbonaceous adsorbents.The adsorption isotherms for AO7 could be well fitted by Freundlich model,implying that the dye adsorption probably occurred on heterogeneous surfaces in a multi-layer manner.The mechanisms of dye adsorption by the carbon were dominated by chemical interactions, probably including electrostatic attraction,π-πelec-tron donor-accepter interaction, and Lewis acid-base interaction. These results demonstrate that the N-doped porous carbon has large BET surface area, well-developed microporosity and high adsorption capacity,thus exhibiting wide applications in various aspects.