竹炭对苯酚吸附的热力学及动力学参数的研究

Study on the Kinetic and the Thermodynamic Parameters for Adsorption of Phenol by Bamboo-charcoal

研究了竹炭对水相中苯酚吸附的动力学和热力学参数。动力学实验表明:竹炭对苯酚的吸附拟用准一级动力学处理。并测定不同粒径、不同温度下竹炭对苯酚吸附的表观速率常数及活化能。热力学研究表明:竹炭对苯酚的吸附符合Langmuir等温吸附方程。测得吸附热ΔH=-14.0 kJ/mol,说明竹炭对苯酚的吸附过程为放热过程,且ΔH<40 kJ/mol,表明吸附过程主要为物理吸附。同时测得吉布斯自由能ΔG<0,且受温度的影响不大,表明吸附质从溶液到吸附剂表面的吸附过程是自发过程。

The kinetic and the thermodynamic parameters for the adsorption of phenol in aqueous solution by bamboo-charcoal were studied. Researches of kinetics showed that adsorption of phenol by bamboo-charcoal can be dealt with pseudo first-order reaction. The apparent adsorption rate constants and activation energy were determined with different sizes of charcoal and at different temperatures. Researches of thermodynamics showed that the adsorption behavior of the bamboo-charcoal for phenol obeys the Langmuir isotherm model. The heat of adsorption is AH = - 14.0 kJ/mol, it means that the sorption process is a exothermic process, and AH 〈 40 kJ/mol means that the sorption process is mostly physical adsorption. At the same time, Gibbs free energy AG 〈 0 indicates that the sorption process is a spontaneous process.