用容量法测定腐植酸含量,其基本原理是在强酸性溶液中,用过量的重铬酸钾将腐植酸中的碳氧化为二氧化碳,根据重铬酸钾的消耗量和腐植酸原料的含碳比,计算出腐植酸的含量。但若试样中含有氯离子,在同样的条件下,重铬酸钾将氯离子氧化为氯气。其反应如下: Cr_2O_7~(-2)+6Cl~-+14H~+→2Cr~++3 Cl_2↑+7 H_2O 由于氯离子氧化消耗重铬酸钾,使测得腐植酸含量偏高。本文通过试验,说明氯离 Determination of humic acid content by volume method, the basic principle is that in a strong acid solution, with excessive potassium dichromate will humic acid carbon into carbon dioxide, according to the consumption of potassium bicarbonate and humic acid raw materials containing carbon Ratio, calculate the humic acid content. However, if the sample contains chloride ions, under the same conditions, potassium dichromate oxidizes chloride ions to chlorine gas. The reaction is as follows: Cr 2 O 7 ~ (-2) + 6Cl ~ - + 14H ~ + → 2 Cr ~ + 3 Cl 2 ↑ + 7 H 2 O Since the oxidation of chloride ion consumes potassium dichromate, the measured humic acid content is high. This article through the test, indicating chloride