磁性构树叶材料的制备及其对阳离子染料的吸附性能

Preparation of the Magnetic Adsorbent Derived from Broussonetia papyrifera Leaves for Cationic Dye Removal

目的:以构树叶为原料,经离子液体预处理后,采用原位共沉淀技术制备磁性构树叶材料,并探讨该吸附剂对阳离子染料的吸附效果。方法:利用红外光谱(IR)和热重分析(TG)对该材料进行初步的结构表征,在此基础上研究了磁性构树叶作为吸附剂对阳离子染料甲基紫、次甲基蓝和罗丹明B的吸附性能,探讨了反应时间、固液比、反应温度、初始浓度对其吸附性能的影响,选择甲基紫的吸附过程对其用四种动力学经验方程和四种热力学模型进行分析。结果:拟合结果表明,吸附过程符合准二级动力学方程,说明该吸附过程以化学吸附为主,其等温吸附过程可以用Langmuir模型描述,说明该吸附以单分子层吸附为主,并提出修订的Langmuir模型。此外,该吸附过程是自发放热的,低温有利于反应的进行。结论:采用原位共沉淀技术制备磁性构树叶材料具有较好的吸附能力,吸附行为符合准二级动力学方程,以及Langmuir吸附等温线。

Objective:Broussonetia papyrifera leaves(BPL)were converted into a novel magnetic adsorbent by a mild method,including pretreatment using ionic liquid and magnetization via a coprecipitation technology.Then resultant magnetic adsorbent was selected to adsorb cationic dyes from aqueous solutions.Methods:The resultant magnetic adsorbent was characterized with infrared spectroscopy(IR)and thermogravimetry(TG).Then the magnetic adsorbent was selected to adsorb cationic dyes,such as Methyl violet(MV),Methylene blue(Mb)and Rhodamine B(RhB),from aqueous solution.Different experimental factors including adsorption time,adsorption temperature,solid-liquid ratio,and initial dye concentration were detected.Furthermore,the adsorption process was analyzed via four kinds of kinetic equations and four isotherm models,respectively.Results:The results show that the process could be described well by pseudo-second-order kinetic and Langmuir isotherm items.In addition,the calculated thermodynamic parameters indicated that the adsorption of MV was spontaneous and exothermic,and a relatively lower temperature was conducive to the adsorption.Conclusion:The magnetic adsorbent derived from BPL still exhibited a good adsorption capacity.And the adsorption behavior was consistent with the pseudo-second-order reaction kinetic and the Langmuir adsorption isotherm.