Morphological Analysis Of Mercury In The Water Environment Of New Technologies And Applications

A new method for speciation of trace mercury in water sample was developed, based on the combination of preconcentration/separation using nanoparticle and determination by CVAAS (cool vapor atomic adsorption spectrometry). The static and dynamic adsorption behavior of Hg( Ⅱ) and phenyl mercury on different nanoparticles were investigated in detail. The optimum conditions for speciation analysis of mercury was determined, the mechanisms for the adsorption and desorption were discussed, and a water sample was analysed by the proposed method with satisfactory results. The followings are the experimental results obtained:1. A fast and convenient way to immobilize nanoparticle onto glass bead was developed and the optimized conditions for the immobilization were found as: 1g of TiO₂ , 1ml of 10%(V/V) Na₂SiO₃ solution and 20g of glass bead mixed with little water, then dried under 105 ℃, and finally calcined under 500℃ for 2 hours. However, the saturated adsorption capacity of nanoparticle suffered from a great loss because the available effective surface area reduced.2. A static preconcentration/separation technique for speciation of mercury using nanoparticle was proposed, which includes surging, centrifugal separation and elution. It was found that 1) Effects of pH on adsorption of Hg(Ⅱ )/phenyl mercury over the nanoparticles were remarkable. The adsorption ratio enhanced with the increase of pH. Excellent adsorption ratio could be obtained when the pH exceed 9.0 for Hg( Ⅱ) and 10.0 for phenyl mercury respectively; 2) The optimum surging time was 12 minutes; 3)15% HCl(V/V) solution could quantitatively elute both Hg( Ⅱ) and phenyl-mercury.3. A dynamic preconcentration/separation technique for speciation of mercury using nanoparticle was proposed, in which the immobilized nanometer TiO₂ was uesd as solid-phase extractant. The results indicated that 1) The dependence of adsorption ratio of Hg( Ⅱ )/phenyl mercury on pH was almost the same as that in the static experiment, and the optimum acidity was pH 10.0; 2) According to the dynamic adsorption and desorption kinetic curves, the flow rate of sample solution was chosen as 0.5ml/min; 3) Effects of both the concentration and the volume of eluent were remarkable. Using 10ml 15% HCl, the...