甲醛改性花生壳对亚甲基蓝的吸附特性研究

Study on the Adsorption Characteristics of Peanut Shells Modified by Formaldehyde to Methylene Blue

［目的］为花生壳在染料工业废水处理中的应用提供理论指导。［方法］通过甲醛改性花生壳对亚甲基蓝的吸附试验，探讨振荡时间、初始浓度、pH值、温度等因素对吸附过程的影响。［结果］15 min内，甲醛改性花生壳对亚甲基蓝的吸附量随时间的延长而快速增加15 min后，吸附量随时间变化增加缓慢。35～55 min内，改性花生壳对亚甲基蓝的吸附量变化较小，55～75 min变化较大，95 min后，基本不再改变。pH值为1～3时，改性花生壳对亚甲基蓝的吸附量随pH值的增加而减小，pH值为3～5时吸附量达到最小值 pH值为5～8时，吸附量增加，pH值大于8时，其吸附量又减小。改性花生壳对亚甲基蓝的吸附过程符合Langmuir与Freundlich模型，其吸附平衡常数与最大吸附量随温度的升高而增大。［结论］该吸附过程为自发的吸热过程且符合二级动力学反应。

[ Objective ] The study aimed to provide theoretical directions for applying peanut shells in disposing dyestuffs wastewater. [ Method ] The influences of factors such as oscillation time, inintial cohen. , pH value and temperature on the adsorption process were discussed through the adsorption experiment on peanut shells modified by formaldehyde to methylene blue. [ Result] In 15 rain, the adsorption quantity of peanut shells modified by formaldehyde to methylene blue was increased quickly as the adsorption time extended. After 15 min, the adsorption quantity was increased slowly as the time extended, the adsorption quantity of peanut shells modified by formaldehyde to methylene blue changed less in 35 - 55 min, changed more in 55 - 75 min and basically had no change after 95 min. When the pH value was 1 - 3, the adsorption quantity of peanut shells modified by formaldehyde to methylene blue was reduced as the pH value was increased. When the pH value was 3 -5, the adsorption quantity was minimum. When the pH value was 5 - 8, the adsorption quantity was increased and when the pH value was higher than 8, the adsorption quantity was reduced again. The adsorption process of peanut shells modified by formaldehyde to methylene blue accorded with Langmuir and Freundlich models and its adsorption equilibrium constant and maximum adsorption quantity were increased as the temperatrue was increased. [ Conclusion] The adsorption process was spontaneous endothermic process and accorded with second kinetics reaction.