功能化SBA-15介孔材料的制备及其吸附性能研究

Synthesis of functionalized SBA-15 mesoporous materials and their adsorption properties

硅基介孔材料因其特有的特性,被用于去除废水中重金属离子的吸附剂.为了提高对目标污染物的吸附容量,本文采用一步法和两步法制备了氨基或巯基功能化SBA-15介孔材料,利用傅里叶红外光谱仪、场发射扫描电镜、X射线衍射仪和氮气吸附脱附表征测试了材料的化学组成、微观形貌和物相结构.测试结果显示经功能化处理后的样品成功地接枝氨基或巯基功能基团.研究发现,经功能化处理后,材料的骨架结构及介孔孔道均未被破坏,但有序性下降且出现少许团聚,物性参数也有一定程度下降,功能化材料对Zn^(2+)、Pb^(2+)、Cr^(3+)和Cu^(2+)的吸附率均有大幅度提高.经氨基或巯基功能化后,SBA-15介孔材料对水体中重金属离子的吸附率有很大提高,但一步法制备的功能化硅基介孔材料因模板剂去除不彻底而影响了对重金属离子的吸附效率,两步法制备的功能化硅基介孔材料对重金属离子的吸附效果更好,说明本文的功能化硅基介孔材料工艺是可行有效的,但两步法合成的功能化介孔材料具有更好的吸附效果.

In order to improve the adsorption capacity of the target pollutants, many scholars have improved the preparation methods of mesoporous materials. However, there are few reports on the effect of the adsorption of metal ions after surface modification of mesoporous materials by different processes. The amine-grafted and mercapto- grafted functionalized mesoporous silica materials were prepared by direct co-condensation and post-synthesis grafting processes and then used as adsorbents to remove the heavy metal ions from the simulated water. The chemical composition, micromorphology and phase structure of the material were tested by Fourier transform infrared spectroscopy, field emission scanning electron microscopy, X ray diffractometer and nitrogen adsorption- desorption. It was found that amino and mercapto functional groups were grafted onto the mesoporous silica materials successfully ~spectively. Mesoporous skeleton structure and pores structure were not destroyed, but agglomeration phenomenon occurred in the functionalized mesoporous silica materials with the downward trend of orderliness and physical parameters. Heavy metal ions adsorption efficiency of Zn2＋ , Pb2＋ , Crs＋ and Cu2＋ were gratly improved after being t^ated by the functionalized mesoporous materials. However, the adsorption capacity of direct co-condensation was affected because the templating agent was not completely removed, while the functionalized mesoporous silica synthesized by post-synthesis grafting process had a satisfactory adsorption effect. The functionalized mesoporous silica material had a good adsorption effect of heavy metal ions, but the functional mesoporous materials prpared by post-synthesis grafting process had an even better effect.