纳米TiO_2胶体分离富集水样中痕量镍研究

利用纳米二氧化钛胶体比表面积大,吸附能力强以及吸附离子沉积后又很容易转化为胶体的特点,提出用纳米二氧化钛胶体富集水样中痕量镍。系统研究了胶体纳米二氧化钛对N(iII)的吸附行为,考察了吸附时间、酸度以及共存离子对吸附行为的影响。研究结果表明:在优化条件下,纳米二氧化钛胶体对N(iII)的吸附率可达99%以上。建立了纳米二氧化钛胶体分离富集与火焰原子吸收光谱联用测定水样中痕量镍的方法。该法检出限(3σ)为4.17μg/L,相对标准偏差(RSD)为2.8%;并且由于纳米二氧化钛胶体吸附镍后不需要脱附,分析过程简便、快速;用于实际水样中痕量镍的测定,结果满意。

Separation and Preconcentration of Ultra-trace Nickel in Water Samples with Nano-sized TiO2 Colloid and Determination by Flame Atomic Absorption Spectrometry

The adsorption behavior of nano-sized TiO2 colloid which has large specific surface area,strong adsorption capacity and selectively ions adsorptions for Ni(II)was systematically studied by using nano-sized TiO2 colloid coupled with flame atomic absorption spectrometry(FAAS).Effects of adsorption equilibrium time,acidity,determination conditions and coexisting ions on adsorption behavior were investigated.With the selective adsorption characteristics of nano-sized TiO2 colloid and standard addition method,the interference of coexisting ions was eliminated.A method for preconcentrating and separating ultra-trace nickel in water samples was established using nano-sized TiO2 colloid as extracting agent.Under the optimizing conditions,the adsorption efficiency of nano-sized TiO2 colloid for Ni(II) reached higher than 99.9%,with the detection limit and relative standard deviation of the method for Ni(II)as 4.17 μg/L and 2.8% respectively.When applying the method to water samples,the recoveries for Ni(II)were 91.0%~99.6%.