Synthesis Of Novel Adsorption Materials And Their Adsorption Properties For Trace Elements

In recent years, preconcentration and determination of trace heavy metal ions in environmental samples have drawn growing attention due to the intensification of environmental problem. However, the direct determination of heavy metal ions by modern spectrometric techniques at trace levels is limited due to their low concentrations and matrix effects. This limitation can be overcome by the use of a separation and preconcentration step.Solid phase extraction is one of commonly used sample preparation techniques. Because of its high recovery, high enrichment factor, short extraction time, simple operation, security, and the ability to combine with different modern detection techniques, it is a very active area in the field of environmental, detection, pharmaceutical and industrial chemistry, etc. Form an environmental and economical point of view, there remains a need to design more selective and effective extractants for toxic form environment. The key of this paper is established method of preconcentration and separation of heavy metals. The synthesis of new sorbents and the parameters affecting the adsorption characteristics have been investigated systematically. The more detailed of this paper have been categorized in the following areas:1.3-chloropropyltrimethoxysilane as silane coupling agent, the immobilization of 4-aminoantipyrine onto bentonite was carried out and it was then used to investigate the adsorption behavior of Cr(â…¢), Hg(â…¡) and Pb(â…¡) ions from aqueous solutions. The separation and preconcentration conditions of analytes were investigated. The developed method has been validated by analyzing certified reference materials and successfully applied to the determination of trace Cr(â…¢), Hg(â…¡) and Pb(â…¡) in water samples with satisfactory results. 2. A simple, sensitive and reliable method was established for the preconcentration of trace concentrations of Er(â…¢) ion using activated carbon modified with benzoyl hydrazine. Samples were determined by inductively coupled plasma atomic emission spectrometry. This method has been validated by analyzing certified reference materials and successfully applied to the analysis of trace Er(â…¢) in Yellow River sediments, orange leaves and balsam pear leaves samples. The results were satisfactory.3. Anew sorbent prepared by immobilizing folic acid on silica gel was used as a new solid-phase extractant(SG-EDA-FA). This sorbent has been developed for the separation of trace Pb(â…¡) in environmental samples. The important characteristics of this method are its short extraction time, high adsorption capacity and high enrichment factor. The developed method has been validated by analyzing certified reference materials and successfully applied to the determination of Pb(â…¡) in environmental samples with satisfactory results.