Method for detecting concentration of free radicals in sodium hypochlorite aqueous solution

A sodium hypochlorite and aqueous solution technology, applied in the field of chemical detection, can solve the problems of expensive equipment, complicated reaction process, expensive instruments, etc., and achieve the effects of low degree of natural oxidation, high product stability, and good linear relationship.

Inactive Publication Date: 2021-01-29
TIANJIN POLYTECHNIC UNIV +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0003] At present, the detection methods of free radicals in aqueous solution include electron spin resonance (ESR), which is the most direct method for detecting free radicals. Although this method is simple and effective, the instrument is expensive and the quantitative analysis is not accurate enough. Different capture agents need to be selected for the base; chemiluminescence (CL) is cheap, highly sensitive, and fast in response, but has poor selectivity and cannot characterize the components well, which is limited in practical application; high performance liquid chromatography (HPLC), and its High sensitivity and low detection limit, but there are also disadvantages such as expensive equipment, complex reaction process, and easy production of intermediate products

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  • Method for detecting concentration of free radicals in sodium hypochlorite aqueous solution
  • Method for detecting concentration of free radicals in sodium hypochlorite aqueous solution
  • Method for detecting concentration of free radicals in sodium hypochlorite aqueous solution

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Effect test

Embodiment 1

[0019] A method for detecting free radical concentration in aqueous sodium hypochlorite solution, comprising the steps:

[0020] (1) Add 2ml of capture agent, 2ml of 10mM ferrous sulfate aqueous solution, 3ml of sodium hypochlorite aqueous solution (pH 7, exposed in air) to a 25mL plugged colorimetric tube, add deionized water to 15ml, and ultrasonically For 20 minutes, heat in a water bath at 37°C for 20 minutes, observe that the solution in the colorimetric tube appears purple, and if purple appears, free radicals are generated, and the absorbance measured at a wavelength of 510nm by a spectrophotometer is 0.658;

[0021] (2) Add 2ml capture agent respectively in 11 colorimetric tubes, then add 0, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1ml, pH=3 10mM ferric chloride aqueous solution, Add deionized water to 15ml (at this time, the concentration of ferric chloride aqueous solution in the colorimetric tube is 0, 0.067, 0.133, 0.2, 0.267, 0.333, 0.4, 0.467, 0.533, 0.6, 0.6...

Embodiment 2

[0025] A method for detecting free radical concentration in aqueous sodium hypochlorite solution, comprising the steps:

[0026] (1) Add 2ml capture agent, 1ml concentration of 8mM ferrous sulfate aqueous solution, 0.5ml sodium hypochlorite aqueous solution (pH is 1, exposed in air) to be tested in 25mL stoppered colorimetric tube, add deionized water to 15ml, Sonicate for 10 minutes, heat in a water bath at 37°C for 10 minutes, observe whether the solution in the colorimetric tube is purple, if purple appears, free radicals are generated, and the absorbance measured at a wavelength of 510nm by a spectrophotometer is 0.281;

[0027] (2) Add 2ml capture agent respectively in 11 colorimetric tubes, then add 0, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1ml, pH=4 8mM ferric chloride aqueous solution, Add deionized water to 15ml, (at this time, the concentration of ferric chloride aqueous solution in the colorimetric tube is 0, 0.053, 0.107, 0.16, 0.213, 0.267, 0.32, 0.373, 0.42...

Embodiment 3

[0030] A method for detecting free radical concentration in aqueous sodium hypochlorite solution, comprising the steps:

[0031] (1) Add 2ml of capture agent, 3ml of 8mM ferrous sulfate aqueous solution, 5ml of sodium hypochlorite aqueous solution (pH 12, exposed in air) to a 25mL plugged colorimetric tube, add deionized water to 15ml, and ultrasonically For 30 minutes, heat in a water bath at 37°C for 30 minutes, observe whether the solution in the colorimetric tube is purple, which will produce free radicals, and measure the absorbance at a wavelength of 510nm with a spectrophotometer to be 0.573;

[0032] (2) Add 2ml capture agent respectively in 11 colorimetric tubes, then add 0, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1ml, pH=2 10mM ferric chloride aqueous solution, Add deionized water to 15ml, (at this time, the concentration of ferric chloride aqueous solution in the colorimetric tube is 0, 0.067, 0.133, 0.2, 0.267, 0.333, 0.4, 0.467, 0.533, 0.6, 0.667mM), ultrason...

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Abstract

The invention discloses a method for detecting the concentration of free radicals in a sodium hypochlorite aqueous solution. The method comprises the following steps of: (1) adding a trapping agent, aferrous sulfate aqueous solution and a sodium hypochlorite aqueous solution to be detected into a colorimetric tube, adding water, carrying out ultrasonic treatment to determine whether the solutionis purple or not, and determining the existence of the free radicals if the solution is purple and measuring theabsorbancy; (2) respectively adding a trapping agent into 11 colorimetric tubes, then adding a ferric chloride aqueous solution with the gradient of 0.1 ml, adding water, carrying out ultrasonic treatment until the solution shows purple gradient, and measuring absorbancy to obtain a corresponding curve of the absorbancy and the concentration of the ferric chloride aqueous solution, because a ratio of the molar concentration of free radicals to the molar concentration of the ferric chloride aqueous solution is 1: 1, acquiring a standard curve of absorbance and free radical molar concentration, and substituting an absorbance value of the sodium hypochlorite aqueous solution to be detected into the standard curve to obtain the free radical molar concentration. By adopting the method, separation is not needed for a system with complex components, the natural oxidation degree is low, the product stability is high, the linear relation with the free radical concentration is good, and the measurement range is wide.

Description

technical field [0001] The invention relates to a method for detecting free radical concentration in sodium hypochlorite aqueous solution, which belongs to the field of chemical detection. Background technique [0002] With the continuous deterioration of water quality and the continuous improvement of water quality standards, membrane separation technology in the field of water treatment has been more and more applied. Membrane separation technology is a physical separation process without phase change and low energy consumption. It has the characteristics of high efficiency, energy saving, pollution-free and convenient operation, and can effectively intercept pollutants, bacteria and viruses. However, during use, pollutants will be adsorbed and deposited on the surface of the membrane or in the pores of the membrane, resulting in smaller or clogged membrane pores, and the resulting membrane fouling problem has become a limiting factor for the use of membrane technology. T...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G01N21/78G01N21/31G01N21/33
CPCG01N21/78G01N21/31G01N21/33
Inventor 赵学辉李思沂张宏伟
Owner TIANJIN POLYTECHNIC UNIV
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