磁性水稻秸秆对亚甲基蓝吸附的平衡特性及动力学研究

Study on equilibrium and kinetics of methylene blue adsorption of magnetic rice straw

为磁性水稻秸秆(MRS)应用于印染废水的处理提供理论依据,采用静态吸附法考察了温度、接触时间、亚甲基蓝(MB)初始浓度、MRS用量等因素对MRS吸附MB的影响,并对其等温吸附和动力学模型进行了探讨。最后,采用扫描电镜对MRS进行了表征。结果表明,当温度为45℃、接触时间为40 min、MB初始浓度为0.05 g/L、MRS用量为0.10 g时,吸附率最高,达97.93%。MRS吸附MB的行为遵循Langmuir等温吸附模型(R^2>0.94)和准二级动力学模型(R^2>0.99),说明吸附过程以化学吸附为主,且较易发生。SEM结果显示,MRS表面发生了明显变化,且Fe_3O_4以颗粒物的形式结合于秸秆表面。因此,MRS作为一种具有良好吸附性能且能实现磁场下快速固液分离的新型吸附剂,可应用于印染废水的处理。

In order to provide the theoretical basis of magnetic rice straw(MRS)applied in printing and dyeing wastewater treatment,the effect of process parameters such as temperature,contact time,initial concentration of MB and the dosage of MRS on MB adsorp⁃tion were discussed by static adsorption method,and the isothermal adsorption and kinetic model were also examined.Furthermore,the MRS was characterized by scanning electron microscopy(SEM).The results showed that the adsorption rate could be up to 97.93%under following conditions:the temperature was 45℃,the contact time was 40 min,the initial concentration of MB was 0.05 g/L,and the dosage of MRS was 0.10 g.And the adsorption data followed Langmuir isotherm model(R2>0.94)and pseudo-second-order kinet⁃ic model(R2>0.99).It revealed that the chemisorption nature of MRS on MB,and the adsorption process was easy to occur.SEM re⁃sults showed that MRS surface had a significant change,and Fe3O4 was bound to the straw in the form of tiny particles.Therefore,MRS as a new type of absorbent which not only has high adsorption efficiency,but also has a good solid-liquid separation performance could be used in the treatment of printing and dyeing wastewater.