两种形貌纳米α-Fe_2O_3@C的制备及其吸附性能

Preparation of Two Morphologies Nanoα-Fe_2O_3@C and Their Enhanced Adsorption

利用分步水热、双氧水氧化辅助pH值调控制备了荔枝状、菱形两种形貌α-Fe_2O_3@C核壳结构的纳米吸附剂.透射电镜测试结果显示:荔枝状α-Fe_2O_3@C粒径为2.5μm,壳层为50nm;菱形α-Fe_2O_3@C粒径约5μm,壳层为10nm.荔枝状α-Fe_2O_3@C、菱形α-Fe_2O_3@C及α-Fe_2O_3对罗丹明B(RhB)的吸附平衡时间均为12h,α-Fe_2O_3对RhB的吸附符合准一级动力学模型;荔枝状与菱形α-Fe_2O_3@C对RhB的吸附同时符合准一级动力学方程与准二级动力学方程;3种材料对RhB的吸附等温线均符合Langmuir方程.3个样品对RhB的吸附脱色效率由高到低的顺序为:荔枝状α-Fe_2O_3@C,菱形α-Fe_2O_3@C,α-Fe_2O_3;核壳结构中的C=O键等活性基团有助于提高吸附作用,加强吸附效果,荔枝状α-Fe_2O_3@C使用4次后脱色率下降15.11%,菱形的α-Fe_2O_3@C使用4次后脱色率仅下降12.56%.

Two different morphologies,litchi form and rhombus form of nano-adsorbentα-Fe_2O_3@C with coreshell structure were prepared using stepwise hydrothermal synthesis method,H_2O_2 oxidation and pH control method.The TEM test shows that the particle size of litchi formα-Fe_2O_3@C is about 2.5μm,and the shell thickness is about50nm;The particle size of rhombus form ofα-Fe_2O_3@C is about 5μm and the shell thickness is about 10 nm.The adsorption equilibrium was achieved in 12 hfor the adsorption of RhB ontoα-Fe_2O_3,litchi formα-Fe_2O_3@C and rhombus formα-Fe_2O_3@C while the adsorption of RhB ontoα-Fe_2O_3 follows Pseudo-first order reaction kinetics,and the adsorption of RhB onto litchi form and rhombus formα-Fe_2O_3@C follows both Pseudo-first order kinetics and Pseudosecond order kinetics.Furthermore,the adsorption of the above three samples are consistent with Langmuir model,The order of adsorption-decoloration efficiency of RhB onto three samples is as follows：litchi formα-Fe_2O_3 @C,rhombus formα-Fe_2O_3@C,α-Fe_2O_3,chemical bond of C=O and active groups in the core-shell structure contribute to improving the adsorption and strengthening the adsorption effect.The decolorization rate of RhB onto rhombus formα-Fe_2O_3@C and litchi formα-Fe_2O_3@C only decreased about 15.11% and 12.56% respectively after 4runs.