改性活性碳纤维对苯胺吸附特性分析

开展了等离子体改性活性碳纤维对苯胺吸附性能的理论和实验研究。通过改变等离子体改性功率和改性时间，探寻最佳改性条件；采用BET、XPS、FTIR、热重测试对改性前后活性碳纤维理化特性进行了表征分析。结果表明，在等离子改性功率为22W，时间为3min时为最佳改性条件；改性后的活性碳纤维对水溶液中苯胺的去除率可达79.3%，去除率提高了8%。微观上等离子体改性使得活性碳纤维表面含氧官能团含量增加，增强对溶液中苯胺的吸附效果。吸附实验结果表明，改性前后活性碳纤维对苯胺的吸附在溶液pH为6时，吸附效果最佳；但达到同一去除率时改性活性碳纤维的速度更快，并且平衡吸附容量也更大。采用准一级和准二级动力学模型对该吸附过程进行描述，其改性前后均用准二级动力学拟合效果更好，表明活性碳纤维结构的特殊性使其对苯胺的吸附以化学吸附为主。活性碳纤维的等离子体改性提高了其对水溶液中苯胺的吸附速度和容量，增强去除效果降低了苯胺对环境的危害。

Characterization of aniline adsorption by modified activated carbon fiber

The theoretical and experimental studies on aniline adsorption performance over plasma-modified activated carbon fibers were carried out. The optimal modification conditions were explored by adjusting the plasma modification power and modification time. The physical and chemical properties of activated carbon fibers before and after modification were characterized by BET specific surface area, XPS, FTIR and TG tests. The results showed that the best modification conditions were achieved at the plasma modification power of 22W and the time of 3min. The aniline removal efficiency in aqueous solution by the modified activated carbon fibers could reach 79.3% and increased by 8% compared to the activated carbon fibers. Microscopically, the plasma modification increased the amount of oxygen-containing functional groups on the surface of the activated carbon fibers, enhancing the adsorption performance of aniline in solution. The adsorption experiment results revealed that the optimal adsorption efficiency of aniline on activated carbon fibers before and after modification was achieved at the solution pH of 6, however, the modified activated carbon fibers were faster and had a bigger equilibrium adsorption capacity when the same removal efficiency was achieved. The pseudo-first-order kinetic and pseudo-second-order kinetic models were used to describe the adsorption process, and the pseudo-second-order kinetic model was fitting better for both before and after modification, which indicated that the unique structure of the activated carbon fiber contributed to the dominated chemisorption of aniline. The plasma modification of the activated carbon fibers increased the adsorption efficiency and capacity of aniline in aqueous solution, enhancing the removal performance and reducing the environmental hazard of aniline.