胞外高聚物分离富集-火焰原子吸收法测定水样中镍

摘要

以胞外高聚物PF-2作为镍的分离富集新材料,利用扫描电镜(SEM)、X射线能量色散分析仪(EDX)和傅里叶变换红外光谱(FTIR)对其进行表征.以火焰原子吸收法为检测手段,研究了胞外高聚物PF-2对水中Ni(Ⅱ)的吸附性能.结果表明:在pH 5.0,此吸附剂对水中的Ni(Ⅱ)具有很强的吸附能力.高聚物PF-2对Ni(Ⅱ)的吸附较易进行,吸附等温线能较好地用Langmuir模型来描述,最大吸附容量为33.5 mg/g.被吸附的Ni(Ⅱ)可用0.5 mol/L HCl定量洗脱.本方法线性范围0.05～2.0 mg/L;检出限为48 μg/L;对80 mg/L Ni(Ⅱ)溶液平行测定9次,RSD为2.6%.本方法已成功地应用于环境样品中痕量镍的测定.%A new exopolymers PF-2 was prepared for separation-preconcentration of trace nickel, and characterized using scanning electron microscope (SEM) . energy dispersive X-ray spectrometry(EDX) and Fourier transform infrared spectrophotometry (FTIR). By means of the determination of flame atomic absorption spectrometry (FAAS) , the adsorption behavior of exopolymers PF-2 for nickel ions was investigated. The results showed that at the optimum pH 5. 0, the Langmuir isotherm fitted well with the experimental equilibrium data, and maximum monolayer adsorption capacity was 33. 50 mg/g. The adsorption kinetics data fitted very well to pseudo second-order model. The adsorbed Ni(Ⅱ) could be quantitatively eluted using 0. 5 mol/L HCl. A linear response of nickel was obtained in the range of 0. 05 - 2. 0 mg/L with a detection limit of 48 μg/L. Under optimum conditions, the relative standard deviation (RSD) was 2. 6% (n = 9, c = 0. 08 mg/L). The proposed method has been applied to determine trace nickel in environmental samples with satisfactory results.