颗粒活性炭吸附苯酚模拟废水的热力学和动力学研究

Thermodynamic and kinetic of phenol simulation wastewater adsorption onto granular activated carbon

研究了颗粒活性炭对苯酚的静态吸附行为,分析了吸附热力学性质和动力学特征。实验结果表明:颗粒活性炭对水中苯酚的吸附量随其初始浓度的增加而增加,吸附6h可以达到平衡;吸附过程符合McKay二级吸附动力学方程,吸附等温线可用Freundlich等温吸附方程描述;颗粒内扩散不是吸附过程唯一的控制步骤。在不同温度下,颗粒活性炭对苯酚的吸附焓变ΔH、吸附熵变ΔS、吸附吉布斯自由能变ΔG均为负值,说明苯酚在颗粒活性炭上的吸附是一个自发、放热的过程,主要是以物理吸附为主。

The static adsorption process of granular activated carbon （GAC） for phenol was studied and its thermodynamic and kinetic characteristics were analyzed. The experimental results show that： With the mass concentration increasing the static adsorption capability for adsorption of phenol by granular activated carbon increased. The adsorption process of phenol reached equilibrium in 6 h. The adsorption of phenol by activated carbon follows the second-order McKay adsorption kinetics equation. The intraparticle diffusion was not the only control step. The equilibrium dada fit the Freundlich equation well; The enthalpy change ΔH, entropy change ΔS and Gibbs free energy change ΔG of the adsorption are all negative at different temperatures, which indicates that the adsorption of phenol onto granular activated carbonis a spontaneous and exothermic process.