物理化学还原法处理-电感耦合等离子体发射光谱(ICP-OES)法测定污染土壤中的六价铬  

Determination of Hexavalent Chromium in Contaminated Soil by Inductively Coupled Plasma Optical Emission Spectrometer after Physical-Chemical Reduction

作　　者：门倩妮 王鹏[1] 孙建伟 冯博鑫 姚薇 MEN Qianni;WANG Peng;SUN Jianwei;FENG Boxin;YAO Wei(Xi′an Center of Mineral Resource Survey,China Geological Survey,Xi′an,Shaanxi 710100,China;Department of Geology,Northwestern University,Xi′an,Shaanxi 710069,China)

机构地区：[1]中国地质调查局西安矿产资源调查中心,西安710100 [2]西北大学地质系,西安710069

出　　处：《中国无机分析化学》2023年第6期536-542,共7页Chinese Journal of Inorganic Analytical Chemistry

基　　金：国家自然科学基金资助项目(42102080);国土空间生态环境地质调查及修复项目(DD20208079)。

摘　　要：定量分析土壤中六价铬Cr(Ⅵ)含量对于生态环境的恢复治理具有重大意义。使用机械球磨-多硫化钙(CPS)物理-化学相结合的处理方法,以电感耦合等离子体光谱仪(ICP-OES)为测试手段,测定污染土壤中的Cr(Ⅵ),同时还探讨了球磨转速、球磨时间和球料比等球磨工艺条件以及还原剂添加量对六价铬浸出浓度的影响。结果表明,当球磨速度500 r/min、球磨时间2 h、球料比12、还原剂添加量为3%时,Cr(Ⅵ)的浸出浓度可显著降低至3.0 mg/kg以下(GB 36600-2018,第一类用地筛选值),大大减少了还原剂的使用量。通过研究碱消解提取过程中的化学反应,控制pH值的条件范围,确保Cr(Ⅵ)的准确测定。同时,碳酸钠、磷酸缓冲溶液、氯化镁在提取过程中的重要作用也不容忽视;在碱消解提取过程中,计算出盐分在提取液中的理论含量,并通过稀释达到降低盐分浓度、拓宽线性范围,减小基体影响的目的。与传统化学还原法相比,物理化学法可以更快、更有效地减少和固化土壤中的Cr(Ⅵ)。Quantitative analysis of hexavalent chromium Cr(Ⅵ)content in soil is of great significance for the restoration and management of ecological environment.The Cr(Ⅵ)in contaminated soil was determined by inductively coupled plasma optical emission spectrometer(ICP-OES)using a combination of mechanical ball milling and calcium polysulfide(CPS)physical-chemical treatment method.At the same time,the effects of ball milling process conditions such as ball milling speed,ball milling time and ball material ratio,as well as the amount of reducing agent added on the leaching concentration of hexavalent chromium were also discussed.The results show that when the ball milling speed is 500 r/min,the ball milling time is 2 h,the ball-to-material ratio is 12,and the amount of reducing agent is 3%,the leaching concentration of Cr(Ⅵ)can be significantly reduced to less than 3.0 mg/kg(GB 36600-2018,the screening value of the first type of land),which greatly reduces the use of reducing agents.By studying the chemical reaction in the process of alkaline digestion and extraction,the pH condition range is controlled to ensure the accurate determination of Cr(Ⅵ).At the same time,the important role of sodium carbonate,phosphate buffer solution and magnesium chloride in the extraction process cannot be ignored.In the process of alkaline digestion and extraction,the theoretical content of salt in the extract is calculated,and the purpose of reducing the salt concentration,broadening the linear range and reducing the influence of the matrix is achieved by dilution.Compared with the traditional chemical reduction method,physical-chemistry methods can reduce and solidify Cr(Ⅵ)in soil faster and more efficiently.

关 键 词：ICP-OES 化学还原 多硫化钙 土壤 六价铬 机械球磨 碱消解 

分 类 号：O657.31[理学—分析化学] TH744.11[理学—化学]