生活垃圾焚烧飞灰浸出液中盐分对AAS测定铅影响的探讨

Study of Pb Determination on Effect of Salts in MSWI Fly Ash by AAS

采用直接火焰原子吸收法(背景校正关、氘灯扣背景法、标准加入法)和ICP-AES测定稳定化生活垃圾焚烧飞灰浸出液中Pb的含量,测定结果存在显著差异,使用直接火焰原子吸收法(背景校正关)测定的Pb的浓度超标,而其他三种方法所测值达标,由于飞灰浸出液中含有高浓度的盐分(Na^+、K^+、Ca^(2+))。为了探究高浓度的盐分对AAS测定Pb所产生的干扰及消除,进行了盐分添加实验研究。研究结果表明:垃圾焚烧飞灰浸出液中高浓度的盐分在紫外区产生的分子光谱与Pb分析线重叠,产生分子吸收干扰,采用氘灯对AAS进行背景吸收校正,大大降低了K^+、Na^+和Ca2^+对Pb测定影响,但是高浓度的Ca2^+(Ca2^+≥1000mg/L)在Pb分析线(283.3nm)有较高的浓度值。

Using direct flame atomic absorption method(background correction off,deuterium lamp deducting background,standard addition)and ICP-AES,the concentration of Pb in the leaching solution of MSWI fly ash was determined and there was a significant difference that the use of direct flame atomic absorption spectrometry(background correction off)determination of the concentration of Pb exceeded the standard,while the determination of other three methods was up to the standard,because of containing high concentration of salts in the leaching solution of MSWI fly ash(Na+、K+and Ca 2+).To study the interference and elimination of high concentration of salts to the determination of Pb by AAS,a salt-adding experiment were conducted.The results indicated that the molecular spectra of the high concentrations of salts in the leaching solution of MSWI fly ash in the ultraviolet region overlap with the Pb analysis lines,produced molecular absorption interference.The background absorption correction of AAS using deuterium lamp,the interference of Na+、K+and Ca 2+to the determination of Pb was greatly reduced,but the high concentrations of Ca 2+(Ca 2+≥1000mg/L)has higher values of wavelength at the Pb analysis lines(283.3nm).