生物炭对亚甲基蓝的吸附动力学

Kinetics of biological activated carbon on blue methylene adsorption

采用静态吸附试验确定生物炭吸附的最适宜温度、振荡速度、亚甲基蓝初始浓度、生物炭投加量及吸附时间的范围,选择吸附温度、亚甲基蓝初始浓度、生物炭的投加量进行正交实验,得到最优吸附工艺条件:反应温度35℃,生物炭的投加量0.4g,亚甲基蓝的浓度45mg/L,生物炭对亚甲基蓝的去除率98.6%,吸附量5.54mg/g.最优条件下的动力学研究表明亚甲基蓝溶质分子在两相界面上进行的吸附达到平衡时,亚甲基蓝浓度与生物炭的吸附量之间符合Freundlich吸附等温线.吸附动力学特性符合准二级吸附动力学,生物炭对于亚甲基蓝的吸附以化学吸附为速率控制步骤.

Suitable temperature, shaking speed, initial concentration of methylene blue, biological activated carbon dosage and adsorption time range were determined by biological activated carbon adsorp- tion test. Then the temperatures, initial concentration of methylene blue, biological activated carbon dosage were chosen to be investigated by the orthogonal experiment, the optimal adsorption process conditions are as follows, reaction temperature of 35 ℃, biological activated carbon dosage of 0.4 g, concentration of methylene blue of 45 mg/L, the removal of methylene blue by biological activated car- bon of 98.6%, the adsorption amount of 5.54 mg/g. Finally, the kinetic study in optimal conditions indiactes that the adsorbed methylene blue concentration and the biological activated carbon accord with the Freundlich adsorption isotherm when the adsorption of solute molecules of methylene blue comes to balance at the interface. The characteristics of adsorption kinetics are consistent with the quasi two stage adsorption kinetics, and biological activated carbon＇s adsorption of methylene blue is controlled by chemical adsorption.