纳米二氧化钛吸附分离-原子荧光光谱法进行水中无机砷的形态分析

Speciation of inorganic arsenic in water samples by nanometer titanium dioxide adsorption/separation coupled with atomic fluorescence spectrometry

目的:建立新颖、准确、可靠的水中无机砷的形态分析方法。方法:利用纳米二氧化钛在不同pH值溶液中对As(Ⅲ)、As(V)吸附能力的差异,调节溶液pH值,可实现As(Ⅲ)、As(V)的分离测定。结果:As(Ⅲ)在pH1-pH12范围内可被纳米二氧化钛完全吸附,As(V)在pH12的溶液中完全不吸附,用浓NaOH溶液调节溶液pH值为12,被纳米二氧化钛吸附的As(Ⅲ)在40 g/L NaOH溶液的洗脱下完全解吸附,可完成As(Ⅲ)的测定。总砷与As(Ⅲ)的差值即为As(V)含量。结论:纳米二氧化钛吸附分离结合原子荧光光谱法进行水中无机砷的形态分析,可得到满意的结果。

Objective：To establish a novel,reliable and precise method for the speciation analysis of inorganic arsenic in water samples.Methods： Based on the fact that nanometer titanium dioxide shows different adsorption ability to As（III） and As（V） in different pH conditions,As（III） and As（V） can be separated and determined by adjusting pH conditions.Results： It was found that As（III） could be adsorbed quantitatively on nanometer TiO2 in the pH range of 1-12 while As（V） could not be adsorbed at pH12.Adjusting sample pH to 12 with concentrated NaOH,adsorbed As（III） by the nanometer TiO2 could be desorbed completely with 40 g/L NaOH solution,then As（III） was obtained.As（V） was obtained by difference of total As and As（III）.Conclusion： Speciation of inorganic arsenic by nanometer TiO2 adsorption/separation coupled with atomic fluorescence spectrometry in water samples can give us satisfactory results.