| Summary: | 碩士 === 中原大學 === 化學研究所 === 91 === Abstract
Surface modification of mesoporous silica gives enormous stimulus to the field of nanostructured organic-inorganic composite materials, opening new horizons for selective organic transformation and material science. By the Surface modification of mesoporous silica MCM-41, inorganic adsorbents modified with EDTA ligands were successfully synthesized. At first, MCM-41 was organofunctionalized by 3-aminopropyltrimethoxysilane (APTMS) on the surface of its nanochannels. EDTA was used to embedded in the nanochannels of mesoporous materials were prepared by the chemical binding of anhydride to the amino-modified surface of MCM-41.
The extraction of transition metals has been investigated using MCM-41 adsorbents modified with ethylenediaminetetraacetic acid (EDTA) as chelating ligands. The metal ions in aqueous solution were coordinated successfully by the ligands on the surface of the adsorbents under moderate conditions. The extractability of the adsorbents was efficient when increasing pH value in metal ions aqueous solution. In general, most metal ions in aqueous solution can be extracted above 90% when pH＞1. MCM-41 modified with EDTA (MCM-EDTA) was shown to be the most effective adsorbent for the extraction of metal ions and to form specific metal-EDTA complexes, with stability constants lying in the order Cu+2＞Pb+2＞Ag+1＞Fe+3＞Ni+2＞Cd+2》Zn+2》As+5≒Mn+2. In addition, MCM-EDTA merely needs a very short time to anchor almost metal ions and increasing weight of the adsorbents can enhance amount of adsorptive metal ions.
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