CNFs/CS 对重金属离子的吸附性能研究

文章用冷冻干燥法制备纤维素纳米纤维/壳聚糖(cellulose nanofibers/chitosan,CNFs/CS)复合材料，并通过傅里叶变换红外光谱(Fourier transform infrared spectroscopy,FTIR)仪和X射线光电子能谱(X-ray photoelectron spectroscopy,XPS)仪对其进行表征，结果表明，CNFs/CS表面有丰富的官能团，如 $ -NH_{2} $、-COOH和-OH。通过批量吸附试验，对CNFs/CS去除废水中Cu(Ⅱ)、Cd(Ⅱ)的条件进行优化，并对试验数据进行动力学模型和吸附等温模型拟合，结果表明，CNFs/CS对Cu(Ⅱ)、Cd(Ⅱ)的吸附均符合拟二阶动力学模型和Langmuir等温模型，且其对Cu(Ⅱ)、Cd(Ⅱ)的最大吸附量分别为181.81、187.89 mg/g；同时热力学分析结果表明，该吸附是自发的吸热过程。

In this work, cellulose nanofibers/chitosan(CNFs/CS) composites were prepared by freeze-drying method and characterized by Fourier transform infrared spectroscopy(FTIR) and X-ray photoelectron spectroscopy(XPS). The results showed that CNFs/CS had abundant functional groups such as $ -NH_{2} $, -COOH and -OH groups. The removal conditions of Cu(Ⅱ) and Cd(Ⅱ) from wastewater by CNFs/CS were optimized by batch sorption experiments, and the experimental data were fitted by kinetic models and sorption isotherm models. The fitting results showed that the sorption of Cu(Ⅱ) and Cd(Ⅱ) on CNFs/CS conformed to the pseudo-second-order kinetic model and Langmuir isotherm model, and the maximum sorption capacities of Cu(Ⅱ) and Cd(Ⅱ) were 181.81 mg/g and 187.89 mg/g, respectively. Meanwhile, the thermodynamic results showed that the sorption was a spontaneous and endothermic process.