3-氨丙基三乙氧基硅烷改性蛭石的制备及其对Pb(Ⅱ)的选择性吸附研究

Preparation of APTES-Verm and its selective adsorption for Pb(Ⅱ)

以天然蛭石(Verm)为原料,通过无机酸改性和有机改性制备出3-氨丙基三乙氧基硅烷改性蛭石(APTES-Verm)。采用傅里叶变换红外光谱仪、热分析仪、场发射扫描电子显微镜、多分子层吸附模型等多种表征手段分析了Verm、酸改性蛭石(a-Verm)和APTES-Verm这3种吸附材料的结构和物理化学性质,并研究了APTESVerm对环境水体中4种常见的重金属污染物———Cu(Ⅱ)、Pb(Ⅱ)、Cd(Ⅱ)、Hg(Ⅱ)离子的吸附性能。结果表明:用无机酸处理后,得到了比表面积增大、表面富含反应性硅羟基(Si—OH)的a-Verm;a-Verm经过进一步的有机改性后,在Si—OH基团的桥梁作用下,接枝上APTES,相应引入了大量对重金属离子具有吸附作用的—NH2基团。制备的APTES-Verm对Pb(Ⅱ)离子的吸附具有明显的选择性,吸附量达到210.865mg/g。

APTES modified vermiculite(APTES-Verm)was synthesized with vermiculite(Verm)by inorganic acid modification and organic modification methods successively.The surface properties and structures of Verm,Acidmodified Verm (a-Verm)and APTES-Verm were analyzed by FT-IR,TG-DTG,SEM and BET.The adsorption test was studied for the four common heavy metal ions,Cu(Ⅱ),Pb(Ⅱ),Cd(Ⅱ)and Hg(Ⅱ)in the environment.The results show that:the surface area of vermiculite was greatly increased by acid modification,and the Si-OH groups were exposed on the surfaces of vermiculite;the organic modification reaction grafted APTES onto the surfaces of a- Verm successfully,introduced a large amount of -NH2 groups with excellent adsorption function;the surface properties of vermiculite were improved by surface modification methods,the adsorption capacity of vermiculite was greatly improved,and the adsorption for Pb(Ⅱ)showed obvious selectivity in comparison with Cu(Ⅱ),Cd(Ⅱ)and Hg(Ⅱ),the adsorption capacity for Pb(Ⅱ)was 210.865mg/g.