Syntheses Of Chelating Resins Based On Polyacylonitrile And Their Application In Analysis Of Heavy Metals

In recent years, heavy metal pollution of marine water is becoming more and more serious resulting from industrial and domestic sewage. The heavy metals accumulated by marine organisms like seaweed, marine fish and shellfish, have already affected quality and safety of aquatic products, threated to human health and life safety. Therefore, it is very important to analyse and detect the heavy metals content of those aquatic products. Because of high complexity of heavy metals classification, low-concentration and complicated matrix, it can not be detected and analysed by conventional measure methods. So there is still a need for sample pre-concentration and enrichment before detection. Chelating resin is widely used in separation and preconcentration of heavy metal ions from aqueous solutions as a kind of functional materials due to its high adsorption selectivity and capacity, easy handling and good reusability.In this paper, basing on the research review of synthesis of chelating resins and their adsorption to heavy metals, the novel functional resins were synthesized by heterocyclic into polyacylonitrile beads and their physical, chemical properties and performance of adsorption as well as desorption of heavy metals on those resins were studied in order to analysis and detection of heavy metals. An excellent resin was selected and applied to analyse mercury in aquatic products. It is mainly manifested as follows:1. Eight heterocyclic organic ligands, containing nitrogen, sulfur, oxygen and other elements which had an excellent selection chelating properties to heavy metal were selected to react with polyacrylonitrile beads by nucleophilic addition reactions and three kinds of new functional chelating resins were screened out and synthesized The optimum synthesis conditions, functional group capacity and functional group conversion were determined by Elemental Analysis and FT-IR, and the resins structure were characterized. The functional group conversion of ATR, ADTR and ABTR was41.10%,34.92%and56.61%, respectively. The functional group capacity was3.94,3.54and3.82mmol/g, respectively. The paths of synthesis were confirmed to be nucleophilic addition reactions which amino of ligands reacted with cyano of polyacrylonitrile beads. It was considered to be High Atom Economy, reflecting the characteristics of green chemistry well.2. The adsorption properties of three kinds of resins for six kinds of common heavy metal ions were studied, focusing on the adsorption behavior of the resin for Hg (II).Batch studies showed that all the three kinds of resins had high selection adsorption capabilities for Hg(II). The statically saturated adsorption capacities of ATR, ATDR and ABTR for Hg(II) were364.3,450.1and458.1mg/g, at pH=6.5,6.6and6.0, respectively; it was found that3mol/L HNO3,4mol/L HCl or4mol/L HNO3,4mol/L HNO3solution provided effectiveness of the desorption of Hg(II) from ATR, ATDR and ABTR respectively; The adsorption kinetics data of Hg(II) onto three kinds of resins were in agreement with pseudo-second-order model; The isotherms adsorption data fitted well to Langmuir model. Thermodynamic parameters indicated that Hg(II) adsorption caused by three kinds of resins was endothermic and spontaneous chemisorption.Column studies showed that the dynamic saturated adsorption capacities of ATR, ADTR and ABTR for Hg(II) were434.0,459.5and470.2mg/g, respectively. Thomas model was reasonably accurate in predicting the experimental breakthrough curves for this work. Dynamic desorption rate of three kinds of resins can achieve100%; during the five-time repeated adsorption-desorption operations, ABTR resin exhibited a better regeneration performance.A comparative analysis of former adsorption and latter adsorption was studied using SEM, EDS, TGA and XPS. SEM, EDS and XPS analysis of resins surface proved the adsorption of mercury. TGA results showed that those the resins were good thermal stability. The operating temperature of ATR and ADTR were apt to be carried out under400℃The operating temperature of ABTR was apt to be carried out under300℃.3. A new method for determination of trace mercury in aquatic product was developed by employing ABTR as a new packing material for microcolumn pre-separation and pre-concentration. The proposed method was applied to the analysis of squid and razor clam samples. The determination results were in accordance with those obtained from ICP-AES. It was suggested that the method can be applied to the analysis of trace mercury in food or other fields.