石墨烯基磁性复合材料吸附水中亚甲基蓝的研究

建立了一种超声辅助共沉淀法制备磁性Fe3O4/氧化石墨烯(Fe3O4/GO)纳米粒子.透射电镜和磁滞回线研究表明,该复合物具有小的颗粒尺寸和超顺磁性.该磁性纳米材料可以吸附废水中的染料亚甲基蓝,实验研究了溶液pH值、吸附剂的用量、时间和温度对亚甲基蓝去除率的影响.结果表明,pH值在6~9范围内,Fe3O4/GO都能高效地吸附亚甲基蓝.反应过程在前25 min反应速率很快,到180 min内达到吸附平衡.该磁性纳米材料对亚甲基蓝的吸附符合Langmuir吸附等温模型和准二级动力学方程,吸附过程是一个自发和吸热过程.该吸附材料对亚甲基蓝吸附容量高,在313 K时Fe3O4/GO的饱和吸附量为196.5 mg·g-1.另外,可以方便地通过外部磁场分离回收吸附剂,利用过氧化氢可以再生重复使用,是一种优良的吸附染料废水的材料.

Adsorption of Methylene Blue from Aqueous Solution onto Magnetic Fe3O4/Graphene Oxide Nanoparticles

A simple ultrasound-assisted co-precipitation method was developed to prepare magnetic Fe₃O₄/graphene oxide (Fe₃O₄/GO) nanoparticles. The characterization with transmission electron microscope (TEM) indicated that the products possessed small particle size. The hysteresis loop of the dried Fe₃O₄/GO nanoparticles demonstrated that the sample had typical features of superparamagnetic material. Batch adsorption studies were carried out to investigate the effects of the initial pH of the solution, the dosage of adsorbent, the contact time and temperature on the adsorption of methylene blue. The results indicated that the composites prepared could be used over a broad pH range (pH 6-9). The adsorption process was very fast within the first 25 min and the equilibrium was reached at 180 min. The adsorption equilibrium and kinetics data fitted well with the Langmuir isotherm model and the pseudo-second-order kinetic model. The adsorption process was a spontaneous and endothermic process in nature. The composite exhibited fairly high adsorption capacity (196.5 mg·g^-1) of methylene blue at 313 K. In addition, the magnetic composite could be effectively and simply separated by using an external magnetic field, and then regenerated by hydrogen peroxide and recycled for further use. The results indicated that the adsorbent had a potential in the application of the dye wastewater treatment.