痕量汞的气热提取应用于现场快速分析污水
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摘要
为测定污水中汞含量,取约25mL水样,加入硫酸亚锡和氨基磺酸的混合物(质量比3∶1)0.40g,反应15min,使汞(Ⅱ)还原为气态单质汞,以0.3L·min~(-1)流量将汞蒸气引入由碘酸钾和硫酸氢铵的混合物(质量比1∶4)0.20g,约5 mL去离子水和1 mol·L~(-1)硫酸溶液0.100mL组成的吸收液中,使单质汞氧化成汞(Ⅱ),随即向此溶液中加入含有镉试剂的汞检测剂0.10g,使汞(Ⅱ)反应显色,2min后进行测定。显色反应时,所加入的汞检测剂中含有氢氧化钠和四硼酸钠组成的缓冲剂(相当于2mol·L~(-1)氢氧化钠溶液0.1mL和四硼酸钠0.04g),曲拉通X~(-1)00(相当于体积分数为10%的曲拉通X~(-1)00溶液30μL)和镉试剂(相当于1g·L~(-1)镉试剂乙醇溶液60μL)。按上述操作流程结合使用便携式专用仪器可在20min内完成一次测定,方法的检出限(3s/k)为2μg·L~(-1)。分别对0.050,0.500mg·L~(-1)汞标准溶液进行精密度试验,测定值的相对标准偏差(n=6)分别为3.6%,5.1%。方法用于废水样品的分析,并进行加标回收试验,测得回收率为92.0%～103%。
For determination of trace amount of mercury in waste water,about 25 mL of the water sample was taken and reacted with 0.40 g of a mixture of SnSO_4 and NH_2 SO_3 H(mass ratio 3∶1)for 15 min to reduce Hg(Ⅱ)to Hg(0)in its vapor state,which was carried over at a flow rate of 0.3 L·min~(-1),into an absorption solution,containing 0.20 g of a mixture of KIO_3 and NH_4 HSO_4(mass ratio 1∶4),about 5 mL of deionized water and 0.100 mL of 1 mol·L~(-1) H_2 SO_4 solution,to oxidize Hg(0)to Hg(Ⅱ).0.10 g of a detection reagent mixture,which contained cadion as chromogenic reagent for Hg(Ⅱ),was then added to the absorption solution,to react with Hg(Ⅱ)to form a colored chelate,and its absorbance was measured after reaction for 2 min.The components in the detection reagent mixture were given as follows:(a)buffer mixture of NaOH and Na_2 B_4 O_7(equivalent to 0.1 mL of2 mol·L~(-1) NaOH solution and 0.04 g of Na_2 B_4 O_7),(b)Triton X~(-1)00(equivalent to 30μL of 10% volume fraction of Triton X~(-1)00 solution),and(c)cadion(equivalent to 60μL of 1 g·L~(-1) alcoholic solution of cadion).The above mentioned procedure was carried out with a portable specialized apparatus and one determination could be completed within 20 min.Detection limit(3 s/k)found for this method was 2μg·L~(-1).Test for precision was made at the concentration levels of 0.050,0.500 mg·L~(-1) of Hg,giving values of RSDs(n=6)of 3.6% and 5.1%respectively.Test for recovery was made by standard addition method using waste water sample as matrix giving values of recovery in the range of 92.0%~(-1)03%.
For determination of trace amount of mercury in waste water,about 25 mL of the water sample was taken and reacted with 0.40 g of a mixture of SnSO_4 and NH_2 SO_3 H(mass ratio 3∶1)for 15 min to reduce Hg(Ⅱ)to Hg(0)in its vapor state,which was carried over at a flow rate of 0.3 L·min~(-1),into an absorption solution,containing 0.20 g of a mixture of KIO_3 and NH_4 HSO_4(mass ratio 1∶4),about 5 mL of deionized water and 0.100 mL of 1 mol·L~(-1) H_2 SO_4 solution,to oxidize Hg(0)to Hg(Ⅱ).0.10 g of a detection reagent mixture,which contained cadion as chromogenic reagent for Hg(Ⅱ),was then added to the absorption solution,to react with Hg(Ⅱ)to form a colored chelate,and its absorbance was measured after reaction for 2 min.The components in the detection reagent mixture were given as follows:(a)buffer mixture of NaOH and Na_2 B_4 O_7(equivalent to 0.1 mL of2 mol·L~(-1) NaOH solution and 0.04 g of Na_2 B_4 O_7),(b)Triton X~(-1)00(equivalent to 30μL of 10% volume fraction of Triton X~(-1)00 solution),and(c)cadion(equivalent to 60μL of 1 g·L~(-1) alcoholic solution of cadion).The above mentioned procedure was carried out with a portable specialized apparatus and one determination could be completed within 20 min.Detection limit(3 s/k)found for this method was 2μg·L~(-1).Test for precision was made at the concentration levels of 0.050,0.500 mg·L~(-1) of Hg,giving values of RSDs(n=6)of 3.6% and 5.1%respectively.Test for recovery was made by standard addition method using waste water sample as matrix giving values of recovery in the range of 92.0%~(-1)03%.
引文
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[4]赵昌平.氢化物发生原子荧光光谱法测定水中砷和汞的方法:102706847A[P].2012-10-03.
[5]李满秀,吕艳华.石蜡相分光光度法测定汞的研究[J].冶金分析,2006,26(5):87-88.
[6]洪水皆,吴水生.汞的胶束增溶分光光度法---以镉试剂或镉试剂2B作显色剂[J].环境科学,1981,2(3):20-24.
[7]喻鹏.用于检测重金属离子电化学传感器的研究[D].长沙:中南大学,2011.
[8]付静.水环境重金属检测的电化学传感器的研究[D].杭州:浙江大学,2007.
[9]魏永革,陈坤,张皓晨,等.一种比色法检测污水中汞离子的试剂盒及其检测方法:105548152A[P].2016-05-04.