Preparation Of Novel Functionalized Adsorbent And Their Adsorption Properties For Trace Metal Ions

Nowadays, with the development of productivity and technology, the pollution of heavy metal has became a global environmental pollution issue, which pose a threat on the health and life of the humanity. Because the quantity of heavy metal contained in the environmental samples and food is very little, and trace amount or even lower is requested to detect regularly, the mission of the modern analytical chemistry is more and more difficult. Although many instrument analysis methods possessing higher selectivity and sensitivity have been developed recently, accurate results can not be reached frequently because of the severe interference caused by matrix effects and other interference in the analytical practice, which makes the separation and enrichment to be requisite。In order to separate, concentrate and analyze the trace amount of heavy metal ions effectively, in this paper three kinds of novel functionalized adsorbents have been synthesized and their adsorption properties for trace components have been investigated systematically. The novelty of this study can be categorized as following:1.2,6-pyridine dicarboxylic acid was immobilized successfully on the surface of nanometer SiO2 after the reaction of the SiO2 with the silane coupling agent (APS). The newly synthesized adsorbent was confirmed by characterized by FT-IR spectroscopy and was used to preconcentrate and separate the trace heavy metal ions from solution prior to their determination by inductively coupled plasma atom emission spectrometry (ICP-AES). In the experiment, the results showed that the modified nanometer SiO2 possessed high selectivity for Hg(Ⅱ) at pH 3. The maximum uptake capacity of the adsorbent for Hg(Ⅱ) was found to be 91.87 mg g-1. The detection limit of this method for Hg(Ⅱ) was 0.09 ng mL-1 with a lower relative standard deviation (R.S.D) less than 1.0%. The method has been applied in selective separation and preconcentration of trace Hg(Ⅱ) from real samples with satisfactory results.2.4-((2-aminoethylimino)methyl)-2-methoxyphenol (AEMMP) was immobilized on activated carbon surface to prepare a new adsorbent which was applied to enrich and separate the trace Cd(II), Cu(II)和Hg(II) ions from solutions. In the experiment, the optimization of some analytical parameters affecting the recovery of the analytes such as pH, eluent condition, shaking time, flow rate and the properties of the adsorbent such as enrichment factor, adsorption capacities, reusability and the capacity of resisting interference were investigated. The method has been applied in selective separation and preconcentration of trace Cd(II), Cu(II) and Hg(II) from real samples with satisfactory results.3.6-((2-aminoethyl)carbamoyl)picolinic acid (AECPA) was immobilized on activated carbon surface to synthesize a novel adsorbent which was applied to enrich and separate the trace heavy metal ions from solutions prior to their determination by ICP-OES. The optimization of experimental condition was studied. Under the optimum conditons, the novel adsorbent displayed excellent selectivity for Hg(II) and the adsorption capacity reached 129.36 mg g-1. The detection limit of the present method for Hg(II) was 0.08 ng mL-1. The new developed technique has been applied in the separation and preconcentration of trace mercury in real samples successfully.