火焰原子吸收法研究纳米钛酸锶钡粉体对铅的吸附性能

以氯化钡、氯化锶和四氯化钛为原料，以草酸作共沉淀剂，采用化学共沉淀法制备了纳米复盐吸附剂——钛酸锶钡粉体，并利用TEM，XRD和FTIR进行了表征。以火焰原子吸收为检测手段，详细考察了该纳米吸附剂对水中铅的吸附性能。结果表明：该法合成的钛酸锶钡粉体外形以棒状为主，平均粒径为36 nm，为纯净的钙钛矿纳米粉体。该纳米粉体对水中的铅具有较强的吸附能力，吸附量受介质的pH值影响较大，当pH值为6.0时，该吸附剂对水中铅的吸附容量可达13 mg·g-1。吸附于纳米钛酸锶钡上的铅可用0.5 mol·L-1的硝酸完全解脱。建立了纳米钛酸锶钡粉体吸附富集，火焰原子吸收法测定水中痕量铅的新方法，该法检出限为11 μg·L-1,相对标准偏差为2.6%。用于地表水中铅的测定，结果满意。

Study on Adsorption Behavior of Nanosized Barium-Strontium Titanate Powder for Lead Ion in Water Using FAAS

Nanosized barium-stroutium titanate (BST) powder，a double salt sorbent, was prepared from BaCl₂,SrCl₂ and TiCl₄ by using oxalate co-precipitate method, and characterized by using transmission electron microscope(TEM), X-ray diffraction (XRD) and Fourier transform infrared spectrophotometer(FTIR). By means of determination with flame atomic absorption spectrometry(FAAS), the adsorption characteristic of lead on the BST powder was investigated. The results showed that the forms of the BST powders are clubbed, highly pure perovskite, and the average particle diameter is 36 nm. Lead can be adsorbed strongly on nanosized BST. The adsorption capacity of BST nanoparticle towards lead was found to be 13 mg·g-1 when the pH is 6.0, and 0.5 mol·L-1 HNO₃ is sufficient for complete elution. A new method for the determination of trace lead based on BST nanoparticle separation/preconcentration and FAAS determination was proposed. The detection limit of this method for lead ion is 11 μg·L-1,and the relative standard deviation is 2.6%. The method has been applied to the determination of trace lead in water samples with satisfactory results.