The Synthesis Of Novel SPE Adsorbent And Its Application For Selective Enrichment Of Heavy Metal Ions

With the rapid development of industrial and agricultural production, environmental problem caused by heavy metal pollution is getting worse in recent years. Due to its accumulation and non-biodegradable characteristics in plants and animals, heavy metals cause a great threat on both environment and human health. Therefore, in order to take corresponding control measures and improve the quality of ecological environment, the analysis and detection of heavy metals in environmental samples are of great significance. Because of the low levels of heavy metals in environmental samples and the serious interference, sample pre-treatment is always required for the separation and pre-concentration of trace heavy metals. Solid phase extraction is a kind of sample pre-treatment technology which has been rapidly developed in recent years with many advantages such as high recovery rate, high selectivity and easy to operation and so on. The development of novel solid phase extraction adsorbents with high selectivity and high adsorption rate is an important direction in the studies of solid phase extraction technology. In this work, two solid phase extraction adsorbents were synthesized and used for the separation and enrichment of lead and mercury. When combined with ICP-MS, a new analysis method for the detection of trace amount of lead and mercury ions was established successfully. The main contents are as follows.1. The pollution status of heavy metal ions was reviewed, including air pollution, water pollution and soil pollution status. Various detection techniques and some common used pre-treatment technologies for heavy metals were discussed. Especially, the application of solid phase extraction for the separation and pre-concentration of six kinds of heavy metals, including arsenic, copper, cadmium, chromium, mercury and lead ions, was summarized with a total of 202 citations.2. With non-toxic amino acids and chloromethyl polystyrene resins as starting materials, two kinds of solid-phase extraction adsorbents, glycine grafted chloromethyl polystyrene resin and L-serine graft chloromethyl polystyrene resin, were designed and synthesized by one-step synthesis reaction. Infrared Spectroscopy verified that two amino acids have successfully grafted on the surface of chloromethyl polystyrene resin by chemical reaction. The stability of the two synthesized SPE adsorbents was also examined in common organic solvents and various acid solutions.3. Selective adsorption performance of the solid-phase extraction adsorbents for lead and mercury was investigated through static adsorption experiments. The effects of p H, adsorption equilibrium time, adsorbent dosage and other parameters on the adsorption percentage of metal ions were studied and optimized. Adsorption isotherm and adsorption kinetics data were fitted by the Langmuir model and pseudo two order kinetic equation, respectively. The selective adsorption experiments showed that the two synthesized solid phase extraction adsorbents exhibited high selectivity toward lead and mercury ions.4. Solid phase extraction micro-columns were prepared by the synthesized solid phase extraction adsorbents and their solid phase extraction properties were investigated such as flow rate of sample solutions and elution, enrichment factor, and interfering ions magnification. Then the adsorbents were used for the enrichment and detection of trace amount of lead and mercury in environmental water and soil samples.5. Based on the above studies, the main results were summarized and conclusions were given. Also, personal suggestions were made for the developing trend of solid phase extraction technology.