竹炭对铜(Ⅱ)吸附的热力学和动力学参数的研究

Study on the Kinetic and the Thermodynamic Parameters for Adsorption of Cu(Ⅱ) by Bamboo-charcoal

研究了竹炭对水相中铜(Ⅱ)吸附的动力学和热力学参数。动力学研究表明:竹炭对铜(Ⅱ)的吸附拟用准一级动力学处理,动力学方程可表示为-ln(1-F)=kt。并测定不同粒径、不同温度下竹炭对铜(Ⅱ)吸附的表观速率常数及活化能。热力学研究表明:竹炭对铜(Ⅱ)的吸附的焓变ΔH=-22.6kJ/mol,说明竹炭吸附过程为放热过程,且ΔH<40kJ/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 Cu（ Ⅱ） in aqueous solution by bamboo-charcoal were studied. Researches of kinetics showed that adsorption of Cu（ Ⅱ） by bamboo-charcoal can be deal with pseudo first-order reaction. The kinetics equation can be represented by the following equation, -In（l-F） = k t. The apparent adsorption rate constants and activated energy were determined with different sizes of charcoal and at different temperature. Researches of thermodynamics showed that the heat of adsorption was AH=-22.6 kJ/mol, it meaned that the sorption process was a exothermic process, and AH〈40 kJ/mol meaned that the sorption process was mostly physical adsorption. At the same time, Gibbs free energyAG〈0 indicated that the sorption process was a spontaneous process.