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    高温裂解-离子色谱法测定煤中卤素的含量

    Determination of Halogens in Coal by Ion Chromatography Coupled with High Temperature Pyrolysis Pretreatment

    • 摘要: 建立高温裂解-离子色谱联用技术检测煤中卤素含量的方法。煤样30.0~40.0 mg在350 mL·min-1富氧条件下经1 100 ℃高温裂解处理后,含卤素组分转化成气体形式被20 mmol·L-1氢氧化钠溶液5 mL吸收后,采用离子色谱电导检测器和IonPac AS18柱测定吸收液中氟、氯和溴的含量,采用离子色谱安培检测器和Ionpac AS11-HC柱测定吸收液中碘离子的含量。结果表明,氟、氯、溴和碘的质量浓度在一定范围内与其峰面积呈线性关系,检出限(3s)分别为3.03,2.47,0.80,8.85 mg·kg-1。精密度试验结果显示测定值的相对标准偏差(n=9)均小于5.0%。按标准加入法对煤样进行回收试验,回收率在83.6%~105%之间。

       

      Abstract: A method was proposed for determination of the halogens in coal using high temperature pyrolysis pretreatment and ion chromatography. The coal sample (30.0-40.0 mg) was treated by pyrolysis at 1 100 ℃ in the oxygen of 350 mL·min-1, and then the gas products of pyrolysis were absorbed in 5mL of 20 mmol·L-1 NaOH solution. F-, Cl- and Br- in the absorption solution were determined by ion chromatography with suppressed conductivity detector and IonPac AS18 column, and I- in the absorption solution was determined by ion chromatography with integrated amperometric detector and Ionpac AS11-HC column. As shown by the results, linear relationships between values of peak area and mass concentration of F-, Cl-, Br- and I- were found in definite ranges, with detection limts (3s) of 3.03 mg·kg-1 for F-, 2.47 mg·kg-1 for Cl-, 0.80 mg·kg-1 for Br- and 8.85 mg·kg-1 for I-. Values of RSD (n=9) for precision test were all less than 5.0%. Test for recovery was made by standard addition method for the coal sample, giving results in the range of 83.6%-105%.

       

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