火焰原子吸收法测定酸洗废液中重金属的应用研究

针对采用火焰原子吸收法直接测定酸洗废液中铬、镍、铅3种重金属数据准确性较差的问题,研究了酸洗废液重金属测定存在的干扰因素及采用标准加入法消除干扰的可行性。结果表明,若用火焰原子吸收法直接测定酸洗废液会受到来自基体的干扰,铬、镍、铅的回收率分别为54.0%、84.9%、89.5%,均出现了回收率不达标的情况。通过干扰试验可知,铬主要受到Fe2+的化学干扰及溶液的物理干扰,镍和铅主要受溶液的物理干扰作用,均使测定结果偏低。镍、铅可直接采用标准加入法测定,R2分别可达0.9991、0.9997,镍、铅的回收率分别为97.5%、101.5%;但对于铬,需先优化测定条件和加入干扰抑制剂后,才能采用标准加入法测定,此时铬的相对标准偏差为1.41%,回收率为104.9%。该测定方法精确度和准确度良好,可用于酸洗废液中重金属的测定。

Study on the application of flame atomic absorption spectrophotometry in determination of heavy metals in waste pickling acid

In view of the poor accuracy of determination of heavy metals such as Cr,Ni and Pb in waste pickling acid by flame atomic absorption spectrophotometry directly,the interference factors in the determination of heavy metals in waste pickling acid and the feasibility of eliminating interference by standard addition method were studied in this paper. The results showed that the recovery rate of Cr,Ni and Pb were 54.0%,84.9% and 89.5%,respectively,if the waste pickling acid was directly determined by atomic absorption spectrophotometry. The recovery rate of Cr,Ni and Pb could not reach the standard. Through the interference test,it was known that Cr was mainly affected by the chemical interference of Fe2+ and physical interference of solution,Ni and Pb were mainly affected by physical interference of solution,resulting in the low determination results. Ni and Pb could be directly determined by standard additon method, R2 were 0.9991 and 0.999 7,respectively,and the recovery rate of Ni and Pb were 97.5% and101.5%, repectively,but for Cr,the determination conditions should be optimized and interference inhibitors should be added. The relative standard deviation of Cr was1.41%,and the recovery rate was104.9%. The method was accurate and precise,and could be used for the determination of heavy metals in waste pickling acid.