Fe_(3)O_(4)复合材料对Cd^(2+)的吸附性能研究

Study on Adsorption Properties of Cd^(2+)by Fe_(3)O_(4) Composite Materials

在碱性条件下,以共沉淀法合成Fe_(3)O_(4),再以正硅酸乙酯和二乙烯三胺为原料,制备出Fe_(3)O_(4)复合材料(Fe_(3)O_(4)-SiO_(2)-NH_(2))。采用FT-IR、VSM和SEM对其结构进行表征,并研究了复合材料对Cd^(2+)的吸附性能。实验结果表明,在T=55℃、t=60 min、Cd^(2+)溶液的初始浓度为100 mg·L^(-1)、Fe_(3)O_(4)-SiO_(2)-NH_(2)的添加量为0.1 g时,该材料对Cd^(2+)的吸附容量为71.4 mg·g^(-1)。其吸附动力学行为更符合准二级动力学,热力学更适合用Langmuir等温吸附模型描述。Fe_(3)O_(4)-SiO_(2)-NH_(2)吸附Cd^(2+)后洗脱再生,经过5次循环使用后,其对Cd^(2+)的去除率仍然大于70%。

The Fe_(3)O_(4) is prepared by coprecipitation under the alkaline conditions,and then the Fe_(3)O_(4) composite materials(Fe_(3)O_(4)-SiO_(2)-NH_(2))are synthesized with tetraethyl orthosilicate and diethylenetriamine as the main raw materials.FT-IR,VSM and SEM are employed to characterize their structures,and the adsorption performance of Cd^(2+)by Fe_(3)O_(4)-SiO_(2)-NH_(2) composites are studied.The results showed that under the conditions of T=55℃,contact time of 60 min,an initial Cd^(2+) concentration of 100 mg·L^(-1) and an amount of Fe_(3)O_(4)-SiO_(2)-NH_(2) composite of 0.1 g,the adsorbent capacity of the composite for Cd2+is found to be 71.4 mg·g^(-1).The adsorption kinetic behavior of Fe_(3)O_(4)-SiO_(2)-NH_(2) composites for Cd^(2+) is consistent with the quasi second-order kinetic and thermodynamics is suitable to be described by Langmuir isothermal adsorption model.The removal rate of Cd^(2+)is still above 70%after five times regeneration of Fe_(3)O_(4)-SiO_(2)-NH_(2) composite materials.