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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%.
The nanometer adsorbents with α-Fe_2O_3 @ C core-shell structure with litchi shape and diamond shape were prepared by step-by-step hydrothermal and hydrogen peroxide oxidation, and the results of transmission electron microscopy showed that the particle size of litchi-like α-Fe_2O_3 @ C And the thickness of shell was 50nm.The particle size of rhombohedral α-Fe_2O_3 @ C was about 5μm, and the shell was 10nm.The effect of litchi-like α-Fe_2O_3 @ C, rhombic α-Fe_2O_3 @ C and α-Fe_2O_3 on RhB, The equilibrium adsorption time of RhB was 12h. The adsorption of RhB by α-Fe_2O_3 conforms to the quasi-first-order kinetic model. The adsorption of RhB by litchi-like and rhombohedral α-Fe_2O_3 @ C conforms to quasi-first-order kinetic equation and pseudo-second order kinetics Equation. The adsorption isotherms of RhB by three materials are in accordance with the Langmuir equation.The order of descending adsorption efficiency of RhB from three samples is as follows: litchi-like α-Fe_2O_3 @ C, diamond α-Fe_2O_3 @ C, α- Fe_2O_3 and C = O bonds in the core-shell structure contribute to improve the adsorption and enhance the adsorption effect. The decoloration rate of the litchi-like α-Fe_2O_3 @ C decreased by 15.11% after 4 times of use. The rhombic α-Fe_2O_3 @ C The decolorization rate decreased only 12.56% after 4 times of use.