竹炭对硝基苯吸附的热力学与动力学参数(英文)

Thermodynamic and Kinetic Parameters for Adsorption of Nitrobenzene by Bamboo-Charcoal

研究竹炭对硝基苯的吸附性能及吸附的热力学与动力学参数。吸附试验表明:竹炭对硝基苯吸附的最佳酸度为pH=5.6;吸附平衡时间为540min;竹炭对硝基苯的吸附遵守Langmuir吸附等温方程。动力学研究表明:竹炭对硝基苯的吸附动力学拟用准一级动力学进行描述,298K时,吸附的速率常数为k298=2.42×10-4s-1,吸附活化能Ea=23.5kJ·mol-1。热力学研究表明:竹炭对硝基苯的吸附是放热过程,吸附热为ΔH=-16.8kJ·mol-1;ΔS=37.9J·K-1mol-1;ΔG=-28.1kJ·mol-1,负的吸附自由能变化值体现了吸附质从溶液到吸附剂表面的吸附过程是自发过程。

The adsorption property, thermodynaInie parameters and kinetie parameters of nitrobenzene with bamboo-charcoal were studied in this paper. The result shows that adsorption equilibrium time is 540min and the bamboo-charcoal shows high adsorption ability for nitrobenzene at the pH of 5.6. Langmuir isotherm model is well obeyed. The studying kinetics shows that the adsorption kineties of bambeo-ehareoal on nitrobenzene can be described by pseudo first-order kinetics. The adsorption apparent rate constant k298 is equal to 2.42×10^-4s^-1 and activation energy Ea is equal to 23.5 kJ·mol^-1 at the temperature of 298K. The studying thermodynamic shows that the adsorption process of bainboo-ehareoal on nitrobenzene is an exothermie process. The heat of adsorption （△H） is equal to -16.8 kJ·mol^-1, entropy change（△S） is equal to 37.9 J·K^1mol^1 and free energy change （△G） is equal to -28.1kJ·mol^-1. The △G is a negative value shows that the adsorption process of adsorbate from solution to adsorbent surface is a spontaneous process.