| With rapid development of industrial production, more and more metal pollutants lead to severe worsening pollutions. It is vital important to determinate the metal ions exactly in the environmental samples. Direct determination of trace elements at low concentrations by modern atomic spectrometric techniques is often difficult, not only because of the insufficient sensitivity of the methods, but also because of matrix effects. Hence, the preliminary separation and preconcentration of trace elements from matrix is often required. The pre-concentration and analysis of trace elements depend on different adsorption materials with higher selectivity and bigger adsorption and appropriate separation methods. In this thesis, several new adsorption materials are synthesized. The methods for synthesis of the adsorption materials and the adsorption selectivity characteristics for trace heavy metals have been investigated systematically. The more detailed novelty of this research can be categorized as following:1. A new solid sorbent, silica gel modified with 4-(2-morinyldiazenyl)-N-(3-(trimeth ylsilyl)propyl)benzamide, was prepared and studied for separation and preconcentration of Sc(Ⅲ) as new solid phase extractant. A reliable method is established for the determination of trace Sc(Ⅲ). Experimental results revealed that only two minute was needed for the adsorption equilibrium, and the maximum adsorption capacity of this sorbent for Sc(Ⅲ) was 600μmol g-1 at pH 4. The detection limit of the method was 0.085μg g-1, and the relative standard deviation was less than 1.3%. Moreover, the method was applied to the separation and pre-concentration of trace scandium in water, plant and soil samples with satisfactory results.2. Silica gel and nanometer SiO2 modified with 4-(2-aminoehtylamino)-N-(2-(2-ami noethyl amino)ethyl)butanamide (SG-AAEB and SiO2-AAEB), were prepared and used as sorbents for the solid phase extraction (SPE) of Cu(Ⅱ), Fe(Ⅲ), and Pb(Ⅱ) prior to their determination by inductively coupled plasma atomic emission spectrometry (ICP-AES). Adsorption efficiencies of the two sorbents toward metal ions were investigated and compared, respectively. The adsorption capacity of SG-AAEB was found to be 12.2, 14.5 and 9.8 mg g-1 for Cu(Ⅱ), Fe(Ⅲ), and Pb(Ⅱ), respectively. In comparison, SiO2-AAEB showed a high selectivity toward Pb(Ⅱ) and presented a much larger adsorption capacity (22.3 mg g-1). Furthermore, the potential applications of SG-AAEB and nanometer SiO2-AAEB for simultaneous preconcentration of trace Cu(Ⅱ), Fe(Ⅲ), and Pb(Ⅱ) from natural samples were performed with satisfactory results.3. A new ionic liquid modified silica gel sorbent, prepared from the reaction of active silica gel with N-3-(-3-triethoxysilylepropyl)-3-methylimidazolium chloride ([(TESP)MIm]Cl), was used as effective solid phase extractants. The separation/preconcentration conditions of the analyte, including effects of pH, shaking time, elution condition, sample flow rate, interfering ions and so on, were investigated in detail. Under the optimal conditions, the maximum static adsorption capacity of Fe(Ⅲ) was 37.0 mg g-1. Based on this, a reliable method is established for the determination of trace Fe(Ⅲ). This sorbant was also successfully applied to the preconcentration of trace Fe(Ⅲ) in the water and biological samples with satisfactory results.
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