预处理废报纸对水中甲基蓝的吸附特性

Adsorption Characteristic of Methylene Blue in Aqueous Solution by Pretreated Waste Newspaper

研究了吸附时间、初始染料浓度和吸附温度对吸附能力的影响,考察了相应的吸附动力学、平衡吸附等温线和吸附热力学。结果表明,拟二级吸附动力学方程可以很好地描述废报纸对甲基蓝的吸附过程;粒内扩散模型分两个阶段,说明粒内扩散并非吸附过程中惟一的速率控制步骤;Freundich和Temkin等温线相比于Langmuir等温线更符合吸附平衡数据;吸附热力学数据表明废报纸对甲基蓝是一个自发、放热的物理吸附过程。废报纸吸附剂可以用乙醇脱附再生,经4次循环仍可保持80%以上的吸附能力。

The adsorption capacity was investigated under various experimental parameters such as contact time, initial dye concentration and temperature. The kinetics,equilibrium and thermodynamic studies were assessed. It was found that adsorption kinetics followed well with the pseudo-second-order equation, and the intraparticle diffusion model showed two steps where intraparticle diffusion was not the only rate controlling step of the adsorption process. The equilibrium data were modeled by Langmuir,Freundlich and Temkin isotherms, which revealed that Freundlich and Temkin isotherms were more suitable to describe the methylene blue adsorption than Langmuir isotherm. The values of thermodynamic parameters demonstrated that the adsorption was a physisorption in a spontaneous and exothermic process. Desorption experiments were conducted, and the adsorbent could be regenerated using ethanol at least four adsorption / desorption cycles, with above 80% recovery.