Study On The Application Of Nanometer-size TiO₂ To Trace V, Pt And Pb In Environmental Water

Trace elements and elemental speciation are the important study field of environmental analytical chemistry. Generally, it is necessary to combine high-efficient asunder technology with high-sensitive determination means. In this thesis, nanometer-size TiO₂ has been applied to the analysis of vanadium, platinum and lead.1. The adsorption properties of solid nanometer-size TiO₂ for V( V) were studied. The adsorption rate can reach above 99 % when the pH value were at the range of 4-10. The adsorption balance time was less than 10 min, adsorption capacities was 6.43 mg·g^-1. Using 2 mL1.5 mol·L^-1 NaOH as eluent, the elution rate was above 95%. A novel method of extreme- trace V(V) preconcentration with nanometer-size titanium dioxide and determination by GFAAS was advanced. The detection limit(3 σ ) of the method was 0. 61 μg·L^-1 , and the relative standard deviation was 8.1%(n=6). Environmental samples experiments were also conducted to test the feasibility of the method, and it came out that the recovery rates were between 91. 2% and 102%.2. A novel method for preconcentrayion of Pt (IV) environmental waters with nanometer-size TiO₂ and determination by GFAAS has been developed. The adsorption rate of nanometer-size TiO₂ for Pt (IV) was above 96.63% at pH 4. Pt(IV) was eluted from nanometer-size TiO₂ with 4 mL 0.17 mol·L^-1 HCL-3% thio urea and determined by GFAAS. The preconcentration factor of this method reached 60. The detection limit(3 σ,n=6) was 0. 021 μg·L^-1, while the relative standard deviation was less than 7.0%, and the recovery was between 94.22%-98.27%.3. A novel method of trace Pb( II) preconcentration with nanometer-size titanium dioxide and determination by GFAAS was advanced. The adsorption properties of liquid nanometer-size TiO₂ for Pb( II) were studied. The adsorption rate can reach above 99 % when the pH value were at the range of 4-10. The adsorption balance time was less than 2 min. Disolved the TiO₂ which had adsorpted Pb(II) and been separated with liquid by centrifuging with 0.3 mL4 mol·L^-1 HNO₃, supplemented it to 5 mL with distilled deionized water and then determined the slurry by GFAAS. The detection limit (3 σ ) of the method was 0.09 μg ·L^-1 and the relative standard deviation was6.2%(n=6). Environmental samples experiments were also conducted to test the feasibility of the method, and it came out that the recovery rates were between 98.65%-99.4%.