中文摘要：

采用煤基炭棒阳极，在氦气／乙炔气氛下直流电弧放电制备了直径0．4μm～0．6μm、长度数十微米的炭纤维。以该微米炭纤维（MCFs）为吸附剂，研究水中镉离子在其上的吸附性能。考察了MCFs的表面性质、时间、溶液pH值及镉离子初始浓度对吸附的影响。实验表明，浓硝酸氧化处理可明显增加MCFs表面含氧官能团数量，吸附能力显著增加；吸附动力学数据符合准二级速率方程。pH值对吸附影响较大。酸性条件下，吸附等温线可用Langmuir方程和Freundlich方程拟合；沉淀发生条件下，可用表面沉淀模型拟合。MCFs的单位质量和单位比表面积的吸附量都很大，当pH=5．50和平衡浓度为2mg·L^-1时其吸附量分别为5．7mg·g^-1和0．058mg·m^-1。结果表明，MCFs在环境保护中显示出潜在应用前景。

英文摘要：

Micro-size carbon fibers （MCFs） with a diameter of 0.4-0.6 Ixm and a length of tens of microme- ters were prepared on a coal-based anode by dc arc discharge in a mixture of helium and acetylene. The adsorp- tion of cadmium ions by the MCFs in solution was studied. The effect of the functional groups, time, pH value and initial concentration of solution on the adsorption of cadmium ions was investigated. Results showed that the acid oxidation resulted in an increase in the number of oxygen-containing groups. The adsorption capacity of the oxidized MCFs increased significantly. The pH value has a great influence on the adsorption of cadmium ions. A kinetic study showed that the adsorption followed the pseudo-second order kinetic adsorption model. Both Lang- muir and Freundlich models described the adsorption isotherms well at pH〈7.00, while the surface precipitation model showed good agreement with the experiment data when deposition occurred. The adsorption capacity, based on the unit weight and the unit surface area, was the larger for the oxidized MCFs than those for the un-ox- idized ones. When the equilibrium concentration was 2 mg. L-1 and pH = 5.50, the adsorption capacities were 5.7 mg. g-1 or 0.058 mg. m-2. These suggested that the MCFs have potential applications in environmental pro- tection.