Separation And Preconcentration Of Trace Rare Earth And Other Elements With Nanometer Alumina And Their Determination By ICP-AES

Nanometer-sized material as a novel function material, which has come into the world in 1980's, has made a great progress in recent years. The regime of nanoparticle is from 1 to 100 nm which falls between the classic fields of chemistry and solid state physics. The smaller of the diameters they are, the more atoms on their surface, and the bigger of the surface area. The surface atoms in nanometer materials are unsaturated and can bind with other atoms. All these characteristics make nanometer materials be an ideal adsorption materials in modern analytical chemistry.In analytical sciences, separation and preconcentration is usually indispensable to improve the sensitivity and selectivity of the analytical method. Solid phase extraction (SPE) is a sample preparation technique that originated in the 1970's and developed from the late of the 1980's, and has the advantage of high preconcentration factor, simple to operate, less pollution to the environment, easy automation, and can be applied to the different samples.The inductively coupled plasma-atomic emission spectrometry (ICP-AES), which had the merits of low detection limit, good precision and accuracy, wide linear range and multi-element simultaneous detection, has been widely applied in trace analysis. By combined SPE with ICP-AES, the analytical performance of the method could be efficiently improved.The aim of this dissertation is to systematically study the adsorption characteristics of some rare earth element (REE) ions on nanometer Al2O3, and to develop a rapid and efficient separation/preconcentration strategy for trace element. The main contents are described as follows:(1) The adsorption behaviors of rare earth elements (La, Eu and Yb) on nanometer alumina were studied in detail. Factors affecting adsorbing, including pH, eluents, coexisting ions were examined and the optimal experimental conditions were established. Based on these results, a new method for the determination of trace La, Eu and Yb in environmental samples by nanometer Al2O3 separation/ preconcentration and ICP-AES detection was proposed.(2) Using a micro-column packed with immobilized 1-phenyll-3-methyl-4-bonzoil-5- pyrazone(PMBP) on nanometer Al2O3 powder as the adsorption material, the retention behaviors of rare earth ions (Sc3+,Y3+and La3+) on the microcolumn were studied with ICP-AES. The conditions for pre- concentration of rare earth ions were optimized, and a new method for the determination of trace amount of Sc, Y and La by ICP-AES after PMBP loaded nanometer Al2O3 micro-column separation/pre-concentration was developed. The proposed method was applied to the determination of trace Sc, Y and La in GBW07605 Tea leaves, and the determined values are in good agreement with the certified values.(3) Using a micro-column packed with nanometer Al2O3 powder as the adsorption material, the adsorption and elution behaviors of Eu, Dy, Ho and their citrate complexes on it were studied with ICP-AES. The results show that REE-citrate complexes could be quantitatively retained by nanometer Al2O3 microcolumn at pH 4, while free REE ions were adsorpted by microcolumn at a higher pH of 7. By selecting of pH 4.5, free REE ions and REE-citrate complexes could be separated by nanometer Al2O3 microcolumn.(4) The adsorption behaviors of Ga, In, T1 on r -mercaptopropytrimethoxysilane ( y -MPTMS) modified nanometer Al2O3 powder under dynamic conditions were studied with ICP-AES, and the optimal conditions for preconcentration of the studied ions were obtained. The proposed method was applied to determinate trace Ga, In and T1 in synthetic water with satisfactory results.