纳米Fe_(3)O_(4)修饰功能化介孔分子筛MS-PC_(20)高效吸附La(Ⅲ)

Efficient adsorption of La(Ⅲ)by functionalized mesoporous molecular sieve MS-PC_(20)modified with nano-Fe_(3)O_(4)

以硅酸钠和氟硅酸为原料,采用非离子表面活性剂聚氧乙烯(20)十六烷基醚(PC_(20)),利用凝胶法制备了介孔二氧化硅(MS-PC_(20))。将MS-PC_(20)经(E)-2-[(羟甲基)亚氨基甲基]-5-甲氧基苯酚(HESI)选择性配体修饰,再在改性材料中加入磁性成分(Fe_(3)O_(4)),成功制备出MS-PC_(20)-HESI和MS-PC_(20)-HESI-Fe_(3)O_(4)-NPs。将它们作为一种新型吸附剂,用于吸附水样中的La(Ⅲ)离子。通过傅里叶红外光谱、扫描电镜和X射线衍射等表征手段,确定复合材料的化学结构、形貌、晶体结构等特征。通过对样品溶液pH、La(Ⅲ)离子初始质量浓度和吸附时间等变量进行考察和优化,探究MS-PC_(20)-HESI-Fe_(3)O_(4)-NPs吸附剂在不同条件下对La(Ⅲ)吸附性能的影响。结果表明:在优化条件下,MS-PC_(20)-HESI-Fe_(3)O_(4)-NPs复合材料对La(Ⅲ)的吸附量为165.68 mg·g^(-1),吸附率高达88.34%,吸附的过程符合伪二阶模型和朗缪尔模型,其不仅吸附速率快,还对目标物种有足够的可及性、高吸附容量和良好的可重用性,并且加入磁性成分可以通过适当的磁场实现方便和经济的磁分离。

A mesoporous silica of MS-PC_(20)was prepared from sodium silicate and fluorosilicic acid using the non-ionic surfactant polyoxyethylene cetyl ether(PC_(20))via the gel method.MS-PC_(20)was modified by(E)-2-[(hydroxymethyl)iminomethyl]-5-methoxyphenol(HESI)selective ligand,and then a magnetic component(Fe_(3)O_(4))was added to the modified material,and MS-PC_(20)-HESI and MS-PC_(20)-HESI-Fe_(3)O_(4)-NPs were successfully prepared.They were utilized as a novel adsorbent for the adsorption of La(Ⅲ)ions in water samples.The chemical structure,morphology,and crystal structure of the composites were characterized by Fourier infrared spectroscopy,scanning electron microscopy,and X-ray diffraction,respectively.The effects of MS-PC_(20)-HESI-Fe_(3)O_(4)-NPs adsorbent on the La(Ⅲ)adsorption performance under different conditions were investigated by examining and optimizing important variables such as sample solution pH,initial concentration of La(Ⅲ)ions,and adsorption time.The results showed that the La(Ⅲ)adsorption onto MS-PC_(20)-HESI-Fe_(3)O_(4)-NPs composite was 165.68 mg·g^(-1)under the optimized conditions with a high adsorption rate of 88.34%,and the process of adsorption conformed to the pseudo-second-order and Langmuir models.MS-PC_(20)-HESI-Fe_(3)O_(4)-NPs composite not only has fast adsorption rate,but also has enough accessibility,high adsorption capacity and good reusability to the target species.And the incorporation of a magnetic component allowed for convenient and economical magnetic separation under external magnetic field.