磁性纳米γ-Fe_2O_3/SiO_2去除水中亚甲基蓝  

Removal of Methylene Blue from Water Using Magnetic Nano γ-Fe_2O_3/SiO_2

作　　者：陈东[1] 曾玉彬[1] 李源[1] 汪勉[1] 李嘉晨[1] 

机构地区：[1]武汉大学动力与机械学院,湖北武汉430072

出　　处：《化工环保》2015年第5期481-486,共6页Environmental Protection of Chemical Industry

摘　　要：以纳米γ-Fe_2O_3为磁性介质制备了磁性纳米γ-Fe_2O_3/SiO_2,并将其用于水中亚甲基蓝的吸附。表征结果显示:制备的γ-Fe_2O_3/SiO_2呈不规则核壳结构,平均粒径为38 nm,比表面积为74.35 m^2/g,比饱和磁化强度为55A·m^2/kg。实验结果表明:γ-Fe_2O_3/SiO_2对亚甲基蓝的吸附适宜在中碱性条件下进行,4 h即可达吸附平衡;在初始亚甲基蓝质量浓度为1 80 mg/L、γ-Fe_2O_3/SiO_2加入量为2 g/L、初始溶液pH为7.0、吸附温度为298 K的条件下,吸附量最高为25.4 mg/g;共存金属离子会降低吸附效率,而少量的腐殖酸则会促进吸附;吸附过程符合准二级动力学方程,颗粒内扩散不是唯一的控速步骤;等温吸附满足Langmuir模型,该吸附是一个物理吸附过程;用乙醇洗涤的γ-Fe_2O_3/SiO_2重复使用4次时仍能保持约80%的原吸附量。Magnetic nano γ-Fe2O3/SiO2 was prepared using nano γ-Fe2O3 as magnetic material, and was used for adsorbing methylene blue from water. The characterization results show that： the product presents irregular core-shell structure with 34 nm of average particle diameter, 74.35 m^2/g of specific surface area and 55 A · m^2/kg of specific saturation magnetization. The experimental results show that： Neutral and alkaline conditions are suitable for adsorption of methylene blue on γ-Fe2O3/SiO2, which can reach equilibrium in 4 h; Under the conditions of initial methylene blue mass concentration 180 mg/L, γ-Fe2O3/SiO2 dosage 2 g/L, initial solution pH 7.0 and adsorption temperature 298 K, the highest adsorption capacity is 25.4 mg/g; Coexisting metal ions may reduce the adsorption efficiency, while a small amount of humic acid can promote the adsorption; The adsorption process accords with the pseudo-second-order kinetics equation, intra-particle diffusion is not the only speed-control step; The adsorption isotherm meets Langmuir model, and the adsorption is a physical process; γ-Fe2O3/SiO2 still maintain 80% of original adsorption capacity after washed by ethanol and reused for 4 times.

关 键 词：γ-氧化铁 二氧化硅 亚甲基蓝 吸附 循环利用 

分 类 号：X703.1[环境科学与工程—环境工程]