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一、方法要求氰酸盐在酸性溶液中完全水解生成氨.2NaCNO+H_2SO_4+4H_2O→(NH_4)_2SO_4+2NaHCO_3,因此,分别测定酸化前和酸化后溶液中氨的含量,即可计算出氰酸盐的含量.测定氨的方法可用直接比色法.在稀溶液中氨与钠氏试剂(碱性碘化汞钾)生成黄色络合物(胶态溶液)其色度与氨含量成正比,可进行比色测定.2K_2[HgI_4]+2NH_3→NH_2HgI_3+4KI+NH_4I废水经处理后留存的余氯对测定氨有干扰,可加入硫代硫酸钠消除之.此外,废水中还含有铜、锡、钙、镁等金属离子,可加入酒石酸钾钠使之生成络合物以防止它们在碱性溶液中生成沉淀干扰测定.
First, the method requires complete hydrolysis of cyanate in acidic solution to produce ammonia. 2NaCNO + H_2SO_4 + 4H_2O → (NH_4) _2SO_4 +2NaHCO_3, therefore, the contents of ammonia in the solution before and after the acidification were measured respectively to calculate cyanic acid Salt content. Determination of ammonia can be used direct colorimetric method in dilute solution of ammonia and sodium reagent (basic mercuric chloride) to form a yellow complex (colloidal solution) its color is proportional to the amount of ammonia, Can be colorimetric determination.2K_2 [HgI_4] +2 NH3 → NH_2HgI_3 +4KI + NH_4I residual chlorine after treatment of ammonia on the determination of interference may be added to eliminate sodium thiosulfate.In addition, the wastewater also contains copper, tin , Calcium, magnesium and other metal ions, potassium sodium tartrate can be added to generate complexes to prevent them from generating precipitate precipitation in alkaline solution interference assay.