Determination of Nickel in Water by Flame Atomic Absorption Spectrometry after Separation/Preconcentration with Exopolymers

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.