氢氧化钠吸收液-离子色谱法测固定污染源废气中的氯气

建立了氢氧化钠吸收液-离子色谱测定固定污染源废气中氯气的方法。研究采样和分析条件,采用50 mL冲击式吸收瓶,以氢氧化钠为吸收液,利用硫代硫酸钠将样品中的次氯酸完全转化为氯离子,过滤后用离子色谱进行分析。可在采样时选择0.3 μm石英滤膜消除颗粒物干扰,在氢氧化钠吸收液前串联硫酸吸收液消除氯化氢干扰。测试结果显示:氯离子曲线线性关系良好,相关系数为0.999 0;方法检出限为0.02 mg/m³,测定下限为0.08 mg/m³;空白加标的相对标准偏差为0.82%~1.4%,加标回收率为98.0%~107%;实际样品基体加标的相对标准偏差为1.8%~2.7%,加标回收率为98.0%~104%。测试结果表明该方法具有较高的精密度和正确度。

Determination of Chlorine in Waste Gas from Stationary Pollution Sources by Ion Chromatography with Sodium Hydroxide Absorption Solution Sampling

Ion chromatography with sodium hydroxide absorption solution sampling is established for the determination of chlorine in waste gas from stationary pollution sources. Through the study of sampling conditions and analysis conditions, 50 mL impact absorption bottle is used, sodium hydroxide is used as the absorption liquid, sodium thiosulfate is used to completely convert hypochlorous acid in the sample into chloride ion, and ion chromatography is used for analysis after filtration. For particulate matter, 0. 3 μm quartz filter is selected to remove the interference during sampling. For the interference of hydrogen chloride, the sulfuric acid absorption liquid can be connected in series before the sodium hydroxide absorption liquid to eliminate the interference. The results show that the curve has a good linear relationship, and the correlation coefficient is 0. 9990. The detection limit is 0. 02 mg/m³ and the lower limit of determination is 0.08 mg/m³ ; The relative standard deviation of blank standard addition is 0.82%-1.4%, and the recovery is 98.0%-107% ;The relative standard deviation of matrix labeling of actual samples is 1.8%-2.7% ;The recovery of standard addition is 98.0%-104% . The method has high precision and accuracy.