Separation and Enrichment of Trace Amounts of Lead with Organo-inorganic Mesoporous Material and Its Determination by FAAS

An organo-inorganic mesoporous material was prepared by the reaction of n-octylamine withγ-mercaptopropyltriethoxysilane in KCl solution,and the product obtained was used for separation and enrichment of trace amounts of Pb(Ⅱ) ions by adsorption.It was found that the organo-inorganic mesoporous material show quantitative adsorption toward Pb(Ⅱ) ion with relatively high selectivity from a solution buffered at pH 6.0 and at the temperature of(20±1)℃.The value of static saturated adsorption capacity attained to 26.37 mg·g~(-1). Lead(Ⅱ) adsorbed on the mesoporous material was desorbed with a mixed solution of 0.2 mol·L~(-1) HNO_3 and 0.5 mol·L~(-1) HOAc,and its content determined by FAAS under prescribed condition.Linear relationship between values of absorbance and mass concentration of Pb(Ⅱ) was kept in the range within 0.80 mg·L~(-1),and the detection limit(3s/k) of the method was found to be 1.5μg·L.Tests for recovery and precision were made by adding standard Pb(Ⅱ) solution at 3 different concentration levels,to waste water samples and analyzed by the proposed method,values of recovery found were in the range of 96.7%to 105.0%,with values of RSD's(n=7) in the range of 1.66%-2.05%.