纳米二氧化钛分离富集-火焰原子吸收光谱法测定水样中痕量铅

摘要

本文提出了纳米 Ti02分离富集火焰原子吸收光谱法测定水样中痕量铅的新方法。考察了铅在纳米 Ti02上的吸附动力学、最佳酸度和吸附容量。实验结果表明：在最佳实验条件下，纳米 Ti02能定量、快速地吸附水中含有的痕量 Pb2+，其静态吸附容量为17.9 mg/g。吸附在纳米 Ti02上的 Pb2+可用0.1 mol/L HNO3+0.1 mol/LCH3COOH 完全洗脱。本法对 Pb2+的检出限为2.57 ng/mL,相对标准偏差为2.45%(n=11, c=0.1µg/mL )，加标回收率在94.5%～102.5%之间。用于实际水样中铅的测定，结果满意。%A new method for the determination of trace Pb based on nanometer-size TiO2 separation and preconcentration with FAAS was proposed. The optimum conditions for adsorption were studied in detail, and the test included sorption kinetics, effect of pH on adsorption ratio, and adsorption capacity. Under the optimum conditions, Pb2+ could be adsorbed and recovered quantitatively. The static adsorption capacity of Pb2+ on nanoneter-size TiO2 was 17.9mg/g, and 0.1mol/L HNO3 + 0.1 mol/LCH3COOH was sufficient for complete elution. The detection limit of this method for Pb2+ was 2.57ng/mL, and relative standard deviation was 2.45% (n=11, c=0.1µg/mL). The recoveries of Pb2+ ranged from 94.5% to 102.5%. The proposed method has been applied for the determination of trace Pb in water samples with satisfactory results.