颗粒玉米芯吸附亚甲基蓝性能研究

Mechanistic Study on Adsorption of Methylene Blue by Granules Corncob

研究了不同影响因素下颗粒玉米芯对亚甲基蓝的吸附特性,并采用扫描电镜对其进行表征。结果表明,3 g粒径为4~6 mm玉米芯颗粒在25℃对120 mg/L 100 m L亚甲基蓝模拟废水去除率达到90%以上;温度较低时Freundlich等温吸附方程拟合效果更优,温度较高时Langmuir等温吸附方程拟合效果则更优;Gibbs自由能变△Gθ和焓变△Hθ为负值,熵变△Sθ为正值,说明吸附过程是自发、放热、表面分子趋于无序进行;langergren准二级动力学方程能更准确描述颗粒玉米芯对亚甲基蓝的吸附过程。

The adsorption characteristics of methylene blue by granules corncob under different influence factors were studied,and the corncob was characterized by SEM. The results show that more than 90 % methylene blue can be removed by 3 g particle diameter of 4-6 mm granules corncob at 25 ℃when its concentration is 120 mg/L. At low temperature,the Freundlich adsorption isotherms can describe well the adsorption process of methylene blue. However, the Langmuir adsorption isotherms is better than Freundlich adsorption isotherms for describing the adsorption process of methylene blue at high temperature. The Gibbs free energy（△Gθ）, enthalpy change（△Hθ） were negative, and entropy change（△Sθ） was positive, indicating that the adsorption process was spontaneous, exothermic, and the surface molecules tend to proceed in disorder. The adsorption kinetics followed langergren pseudo-second-order kinetic equation.