磁性纤维素的制备及对亚甲基蓝的吸附

Preparation of magnetic cellulose and adsorption of methylene blue

为了制备可生物降解的高效吸附材料,以离子液体为溶剂,氯乙酰胺为改性剂,微晶纤维素和四氧化三铁为原料制备磁性纤维素。研究其对亚甲基蓝的吸附行为。考察了溶液pH值、时间和温度对亚甲基蓝的吸附性能的影响。结果表明,吸附的最佳实验条件是反应温度293K;溶液pH值为7。磁性纤维素对亚甲基蓝的吸附符合Langmuir等温吸附模型,最大吸附容量为123.15mg·g^(-1)。磁性纤维素对亚甲基蓝的吸附动力学符合准二级动力学方程。热力学参数吸附自由能变、吸附焓变和吸附熵变均为负值,表明吸附过程为放热、自发反应过程。离子液体是一种绿色、溶解性强的溶剂,对环境无污染,且制备的磁性纤维素可方便的通过外部磁场分离回收。磁性纤维素是一种优良的吸附染料废水的材料。

In order to get biodegradable and efficient adsorbent,magnetic cellulose was prepared with microcrystalline cellulose and ferric oxide with chloroacetamide as a modifier using ionic liquid as solvent.The adsorption behavior for the removal of methylene blue was studied.Moreover,the enfluence of pH,contact time and temperature on adsorption of methylene blue were investigated.It was found that the optimum conditions for adsorption were as follows:the temperature was 293 Kand pH of the solution was 7.The adsorption of methylene blue by magnetic cellulose was conformed to fit Langmuir isothermal adsorption model,and the maximum adsorption capacity was 123.15 mg·g-1.The adsorption kinetics followed pseudo-second-order kinetic equation.Thermodynamic parameters such as Gibbs free energy change,adsorption enthalpy change and entropy change were all negative indicating that the adsorption process was an exothermic and spontaneous process.Ionic liquid is a green solvent with strong solubility.It has no pollution to the environment,and the magnetic cellulose prepared can be easily separated by external magnetic field.Thus,magnetic cellulose is a good material for treating dye wastewater.