Chlorine Oxygen Consumption Curve Calibration-Sealed Digestion Method for Determination of Cod in High Chlorine Water

A technology of curve correction and digestion method, which is applied in the field of chlorine oxygen consumption curve correction-sealed digestion method to measure COD in high-chlorinated water, can solve the problems of inappropriateness, etc., and achieve the effects of easy observation, good reproducibility, and shortened digestion time

Inactive Publication Date: 2011-12-14
QINGHAI INST OF SALT LAKES OF CHINESE ACAD OF SCI
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Potassium dichromate oxidation method is suitable for the COD value greater than 30mg L -1 Water samples containing Cl are not suitable - Concentration greater than 1000mg L -1 of saline

Method used

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  • Chlorine Oxygen Consumption Curve Calibration-Sealed Digestion Method for Determination of Cod in High Chlorine Water
  • Chlorine Oxygen Consumption Curve Calibration-Sealed Digestion Method for Determination of Cod in High Chlorine Water

Examples

Experimental program
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Effect test

Embodiment 1

[0032] Embodiment 1 The method of chlorine oxygen consumption curve correction-sealed digestion method for measuring COD in high-chlorinated water comprises the following steps:

[0033] (1) Superior grade pure sodium chloride is mixed with a series of sodium chloride solutions of different concentrations, Cl in this sodium chloride solution - The concentration is 2.5~20g L -1 .

[0034] (2) Absorb Cl separately - Put 10.00mL of sodium chloride solutions with different concentrations in a 100mL pressure melting bomb, add MnSO 4 0.6g, c (1 / 6K 2 Cr 2 o 7 )=0.25mol L -1 20mL of potassium dichromate solution and 25mL of concentrated sulfuric acid were digested together with a blank of distilled water in a drying oven at 130°C for 30min at constant temperature.

[0035] (3) Take out the pressure dissolving bomb, after cooling to room temperature, transfer the solution inside to the Erlenmeyer flask, add 1mL of concentrated phosphoric acid and 3 drops of 1,10-phenanthroline ...

Embodiment 2

[0041] Embodiment 2 The method of chlorine oxygen consumption curve correction-sealed digestion method for measuring COD in high-chlorinated water comprises the following steps:

[0042] (1)~(4) are the same as embodiment 1.

[0043] (5) Take 10.00mL of Dongtai Jinel Salt Lake brine and dilute it into a 100mL volumetric flask, so that Cl - The concentration is 14.63g L -1 .

[0044] Get 10.00mL of diluted brine in the pressure melting bomb, and measure the apparent COD value according to the experimental procedure in Example 1; then according to the curve equation COD (Cl)=196.78C Cl - +7.91 to calculate the COD(Cl) value; finally, subtract the COD(Cl) value from the apparent COD value to get the actual COD value in the brine—the COD value in the Dongtai Jinel Salt Lake brine diluted 10 times is 277.0mg L -1 .

Embodiment 3

[0045] Embodiment 3 The method of chlorine oxygen consumption curve correction-sealed digestion method for measuring COD in high-chlorinated water comprises the following steps:

[0046] (1)~(4) are the same as embodiment 1.

[0047] (5) Take 15.00mL of Dachaidan Salt Lake brine and dilute it into a 250mL volumetric flask, so that Cl - The concentration is 10.79g L -1 .

[0048] Get 10.00mL of diluted brine in the pressure melting bomb, and measure the apparent COD value according to the experimental procedure in Example 1; then according to the curve equation COD (Cl)=196.78C Cl - +7.91 to calculate the COD(Cl) value; finally, subtract the COD(Cl) value from the apparent COD value to get the actual COD value in the brine—the COD value in the brine of Dachaidan Salt Lake diluted 16.7 times is 188.2mg L -1 .

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Abstract

The invention relates to a method for measuring COD in high-chlorinated water by a chlorine oxygen consumption curve correction-sealed digestion method. The method comprises the following steps: (1) preparing sodium chloride solutions of different concentrations; (2) adding the sodium chloride solution to In the pressure dissolution bomb, add MnSO4, potassium dichromate solution, and concentrated sulfuric acid in sequence, and digest it together with the distilled water blank in a drying oven at a constant temperature; (3) Take out the pressure dissolution bomb, and after cooling, titrate with ferrous ammonium sulfate solution to calculate the COD (4) take Cl-concentration as the abscissa and COD (Cl) as the ordinate, draw the chlorine oxygen consumption curve; (5) process the high chlorine water sample to be tested according to step (2) and step (3) successively , to obtain the apparent COD value; according to the Cl- content in the high-chlorinated water sample to be tested, the COD(Cl) value is obtained from the chlorine oxygen consumption curve, and the apparent COD value is subtracted from the COD(Cl) value to obtain the high-chlorinated water sample to be tested. The actual COD value of the water sample. The invention has the advantages of simple operation, good reproducibility, good accuracy, saves time, reduces pollution, and is easy to realize batch measurement.

Description

technical field [0001] The invention relates to a method for measuring COD, in particular to a method for measuring COD in high-chlorinated water bodies by a chlorine oxygen consumption curve correction-sealed digestion method. Background technique [0002] COD is defined in the "Water and Wastewater Standard Test Method" as: the determination of the oxygen equivalent required for the oxidation of organic substances that are susceptible to oxidation by strong chemical oxidants in the sample. According to this definition, COD represents the content of organic matter in water, but due to the variety of organic matter in water, complex composition, and a large number of inorganic reducing anions, these have brought certain difficulties to the determination of COD. [0003] my country is a country rich in brine resources (surface brine, intercrystalline brine, underground oil and gas field brine, etc.), and there are a large number of surface brine and intercrystalline brine sal...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G01N21/78
Inventor 李武宋茜茜钱桂敏徐斌李新宁
Owner QINGHAI INST OF SALT LAKES OF CHINESE ACAD OF SCI
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