AEP作用下溶胶-凝胶法制备纤维素基炭气凝胶及其对水溶液中Cu^(2+)吸附性能

Carbon Aerogels Prepared Based on Sol-Gel Reaction of Cellulose Colloid with AEP and Its Adsorption of Copper Ions in Aqueous Solution

以微晶纤维素为前驱物,在表面活性剂异辛醇聚氧乙烯醚磷酸酯(AEP)作用下进行溶胶-凝胶反应,经过真空冷冻干燥后得到纤维素气凝胶,再在600℃惰性气氛中碳化反应制备成炭气凝胶。通过扫描电镜、BET比表面测定和红外光谱表征制备的炭气凝胶孔隙结构及表面官能团,并采用静态吸附法考察了炭气凝胶对水溶液中铜离子的吸附性能。结果表明,溶胶-凝胶反应中的AEP能够有效调节和改进制备的炭气溶胶孔隙结构及其吸附性能。添加2%的AEP得到的纤维素凝胶制备炭气凝胶CCA2孔隙结构发达、均匀,具有655.4 m^2/g的比表面积和0.73 cm^3/g的孔容,对水溶液中Cu^(2+)的吸附容量最大可达到86.27 mg/g,吸附等温线符合Langmiur模型,吸附过程遵循准二级动力学方程。

A novel cellulose-based carbon aerogel with well-developed porous structure and surface group of hydroxyl was synthesized from cellulose aerogel by means of Sol-Gel reaction, freeze-drying and carbonization. In this preparation, cellulose was taken as carbon precursor and phosphate of polyoxyethylene isooctyl ether（AEP） was chosen as structure inducer of micelle in cellulose colloid. Thermal decomposition of the prepared cellulose aerogel was studied by TG technique; the properties of the prepared carbon aerogel, such as porous structure and function groups were characterized with SEM, N_2 adsorption-desorption isotherms and Fourier-transform infrared spectroscopy（FT-IR）. Adsorption of copper ion onto the test samples in aqueous solution was investigated through a static adsorption method. Results show that AEP can obviously regulate the porous structure and improve the adsorption performance of the prepared samples. The optimal sample of the prepared carbon aerogel possesses predominant pore structure of three-dimensional network, with a surface area of 655.4 m^2/g and total pore volume of 0.73 cm^3/g. The maximum copper ion adsorption capacity reached 86.27 mg/g in aqueous solution. In adsorption process, it is also found that the kinetics nicely follows pseudo-second-order rate expression, while the isotherm fits Langmuir model, displaying good adsorption properties. Therefore, the prepared carbon aerogel may have potential application in treatment of metal ion pollution in water. Meanwhile, the preparation strategies in this study provides a novel pathway for preparing carbon adsorbent with specific pore structure and functional groups on the surface.