巯基棉富集大气中汞的有效解吸方法研究

Investigating Effective Desorption Methods for Mercury in the Air by Sulfhydryl Cotton Enrichment

研究了DMA-80测汞仪对巯基棉富集汞的高效解吸方法。常温定速、定量洗脱巯基棉中汞发现,4.0 mol/L盐酸-氯化钠饱和溶液洗脱巯基棉中汞的效率为25%,而0.28%硝酸-3.5%氯化钠溶液(质量比为1∶12.5)洗脱汞效率不到5.6%,表明多数汞仍被富集,但4.0 mol/L盐酸-氯化钠饱和溶液洗脱巯基棉中汞效率稍高。用3种不同解吸方法探究巯基棉中汞回收率发现,超声波解吸汞效率高、耗时短,且低盐、低酸度、低成本的0.28%硝酸-3.5%氯化钠溶液可实现巯基棉中汞的高效洗脱;以4.0 mol/L盐酸-氯化钠饱和溶液及0.28%硝酸-3.5%氯化钠溶液分别为洗脱介质的微波消解法洗脱汞效率高于94.5%;正交试验得出洗脱介质为0.65 mol/L盐酸-氯化钠饱和溶液在95℃电热板中消解4 h含汞巯基棉后,解吸汞效率高于90%。

Investigating effective desorption methods for the enrichment of mercury in sulfhydryl cotton was studied in detail by DMA-80 mercury analyzer. The desorption efficiency for mercury in eluted mercapto-cotton by the mixed solution composed of 4. 0 mol/L hydrochloric acid and sodium chloride saturated solution was 25%,while the elution efficiency for mercury by the mixed solution composed of the mass concentration of 0. 28% for nitric acid and 3. 5% for sodium chloride（ mass ratio for 1∶ 12. 5） was less 5. 6% through constant speed and quantitative conditions at room temperature,both of which showed that most of mercury were firmly adsorbed by sulfhydryl cottons and the elution efficiency of mercury for 4. 0 mol/L hydrochloric acid and sodium chloride saturated solution was more higher. Three different desorption methods were used to elute the mercury and studied the recovery efficiency of mercury by directly adding property mercury to the sulfhydryl cotton with low mercury content and stable content and using different elution solutions. The ultrasonic desorption efficiency of mercury in sulfhydryl cotton was good and assumed short time,the mass concentration of 0. 28% for nitric acid and 3. 5% for sodium chloride（ mass ratio for 1∶ 12. 5） with low salt,low acidity and low lost could meet efficient desorption of mercury in sulfhydryl cotton; the recovery efficiency of mercury in sulfhydryl cotton by two desorption elution solutions of 4. 0 mol/L hydrochloric acid and sodium chloride saturated solution and the mixture solution for the mass concentration of 0. 28% for nitric acid and 3. 5% for sodium chloride using microwave digestion were above 94. 5%; the recovery efficiency of the mercury reached more than 90% under the optimal conditions by orthogonal experimental design for 0. 65 mol/L hydrochloric acid and saturated sodium chloride solution as eluent and digesting time for 4 h by heating plate method at 95 ℃.