Studies Of Silica Gel Supported Ditopic Ligands With Amide Group For Metal Salts Extraction

In this thesis, four types of new silica gel functionalized with ditopic zwitterionic Schiff base and their reduced derivatives were prepared and subsequently applied for the adsorption of metal ions and anions of metal salts solutions, coupled with ICP and IC measurements. The main results are listed as follows:1. Two types of Schiff base were synthesized by using 5-methylsalicylaldehyde、isonipecotamide、dipropylenetriamine and triethylenetetramine. The Schiff bases were also reduced to their deravatives by Na BH4.2. Silica gel was modified with 3-chloropropyltrimethoxysilane and then Schiff base ligands and their reducd derivatives were grafted onto the modified silica gel for preparation of four types of solid-phase extractants. The functionalized silica gels were characterized by Fourier transform infrared spectroscopy, elemental analysis,thermogravimetric analysis and porous structure analysis. The results suggested that the ditopic ligand extractants were prepared successfully, and the reducing Schiff base is better then the Schiff base. The TG results indicated that the themal stability of the adsorbents was favorable.3. The static adsorption, competitive adsorption, effect of p H, contact time and initial concentration parameters on the simultaneous adsorption of cations and anions were investigated. The results showed that the simultaneous adsorption for cations and anions exists. The extraction efficiency of Cu2+ is better than the other cations(Co2+、Ni2+、Mn2+、Cd2+). The effects of p H value on the adsorptive properties of the adsorbents showed that the extraction ratio of Cu2+ increased with increased p H,and the extraction of sulfate was reduced with the increase of p H value. The adsorption equilibrium data of Cu2+ and SO42- were fitted better to Langmuir adsorption model and kinetics studies of Cu2+ revealed that the adsorption processes followed a pseudo second-order model. The regeneration experiment suggested that the solid-phase extractants possess well desorption and regeneration capacities.4. In this paper, twelve new complexes were synthesized and characterized by Fourier transform infrared spectroscopy, UV spectroscopy and mass spectroscopy.The results showed that the Schiff base was coordinated with metal salts.