FAAS Determination of Silver in Fireworks After Separation and Enrichment by Adsorption on Mesoporous Molecular Sieve P123-SH

The mesoporous molecular sieve P123-SH was prepared,and the condition for adsorption of Ag+-ion was studied.It was found that in an aqueous medium of pH 3.6,the mesoporous molecular sieve P123-SH behaved to adsorb Ag+-ion strongly and equilibrium of adsorption was achieved by shaking for 10 min at the temperature of (20±1) ℃,and the adsorptive capacity of Ag+-ion at equilibrium was 15.97 mg·g-1,giving the adsorption rate of 98.5%.The Ag+-ion adsorbed on the surface of mesoporous molecular sieve P123-SH was completly desorbed with 5 mL of a mixed solution of 0.2 mol·L-1 HCl and 0.1 mol·L-1 thiourea,and the silver content was determined by FAAS.Linear relationship between values of absorbance and mass concentration of Ag+-ion was obtained in the range of 0.008-0.24 mg·L-1,with detection limit (3σ) of 0.64 μg·L-1.The proposed method was applied to the determination of silver in firework,giving values of recovery in the range of 97.5%-115.0% and RSD (n=7) 2.4%.