Method for assisted determination for unknown arsenic form in wastewater based on electrochemistry system

An electrochemical and three-electrode system technology, applied in the field of detection, can solve the problems of high cost, stay in the prediction stage of complex ions, and cannot real-time in-situ detection, etc., and achieve the effect of simple operation and low cost.

Active Publication Date: 2015-03-11
CENT SOUTH UNIV
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  • Application Information

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Problems solved by technology

Although the possible complex forms of arsenic in aqueous solution have been gradually reported, most studies are still at the stage of predicting the complex ions
Among the existing detection methods, ion chromatography, liquid chromatography-mass spectrometry, infrared, and Raman can qualitatively or semi-quantitatively detect complex ions, but t

Method used

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  • Method for assisted determination for unknown arsenic form in wastewater based on electrochemistry system
  • Method for assisted determination for unknown arsenic form in wastewater based on electrochemistry system
  • Method for assisted determination for unknown arsenic form in wastewater based on electrochemistry system

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0033] Prepare 1mol / L NaAsO with deionized water 2 solution, 1mol / L Na 2 CO 3 solution and 0.1mol / L Na 2 SO 4 solution. With 0.1mol / L Na 2 SO 4 The solution is a supporting electrolyte, and the preparation series As(III)+CO 3 2- (HCO 3 - ) experimental solution, As(III) and CO in the experimental solution 3 2- The concentration is (1+0), (1+1), (1+2), (1+4), (1+8), (1+16), (0+16)mmol / L, and hydrogen Sodium oxide and sulfuric acid were used to adjust the pH of the solution to 10.00.

[0034] Each experimental solution was magnetically stirred at a speed of 500rpm for 30min, with a gold electrode as the working electrode, a glassy carbon electrode as the counter electrode, and a saturated calomel electrode as the reference electrode, and scanned from 0.2V forward voltammetry to 1.0V, the scanning speed Both are 50mV / s. A total of 7 curves were obtained, see the results figure 1 .

[0035] Such as figure 1 Shown: There is an obvious oxidation peak near 0.6V on th...

Embodiment 2

[0037] Prepare 1mol / L NaAsO with deionized water 2 solution, 5mmol / L of H 2 SO 4 solution. Prepare 0.05mol / L Fe with dilute sulfuric acid with a pH value of 2 2 (SO 4 ) 3 Solution, namely 100mmol / L Fe(III) solution. With 5mmol / L H 2 SO 4 The solution is used as a supporting electrolyte, and a series of As(III)+Fe(III) experimental solutions are prepared. The concentrations of As(III) and Fe(III) in the experimental solutions are (0+10), (5+10), (10+10 ), (20+10), (25+10), (25+0)mmol / L. Adjust the pH to 2 with sodium hydroxide and sulfuric acid.

[0038] Each solution was magnetically stirred at a speed of 500rpm for 30min, with a gold electrode as the working electrode, a glassy carbon electrode as the counter electrode, and a saturated calomel electrode as the reference electrode. Both are 50mV / s. A total of six curves were obtained, the results are shown in figure 2 , the experimental solution corresponding to the uppermost curve is a 25mmol As(III) solution wit...

Embodiment 3

[0041] Prepare 0.1mol / L Na with deionized water 3 AsO 4 solution, 5mmol / L of H 2 SO 4 solution. Prepare 0.05mol / L Fe with dilute sulfuric acid with a pH value of 2 2 (SO 4 ) 3 Solution, namely 100mmol / L Fe(III) solution. With 5mmol / L H 2 SO 4 The solution is used as a supporting electrolyte, and a series of As(V)+Fe(III) experimental solutions are prepared. The concentrations of As(V) and Fe(III) in the experimental solutions are (0+1), (0.5+1), (1+1 ), (2+1), (2.5+1), (2.5+0)mmol / L, adjust the pH value to 2 with sodium hydroxide and sulfuric acid.

[0042] Each solution was magnetically stirred at a speed of 500rpm for 30min, with a gold electrode as the working electrode, a glassy carbon electrode as the counter electrode, and a saturated calomel electrode as the reference electrode. Both are 50mV / s. see results image 3 , the experimental solution corresponding to the uppermost curve is 2.5mmol / L As(V) solution without Fe(III), and the lower ones are (2.5+1), (2...

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Abstract

The invention discloses a method for assisted determination for an unknown arsenic form in wastewater based on an electrochemistry system. The method comprises the following steps: (1) establishing a three-electrode system: taking a gold electrode or a platinum electrode as a working electrode, taking a glassy carbon electrode as a counter electrode, and taking a saturated calomel electrode as a reference electrode; (2) preparing an experiment solution : using a sodium sulphate solution or a sulfuric acid solution as a supporting electrolyte to prepare the experiment solution, and using sodium arsenite, sodium arsenate, sodium carbonate and ferric sulfate to prepare an As (III)-CO32-(HCO3-) solution, an As (III)-Fe (III) solution and an As (V)-Fe (III) solution; (3) carrying out linear scanning detection. Based on the oxidation-reduction reaction and electrochemical principle of arsenic, the method adopts the linear scanning voltammetry of the three-electrode system to capture the change of a corresponding oxidation reduction potential when the arsenic form is changed, thereby predicting the unknown arsenic form in the wastewater containing arsenic. The method implements regulation and controlling for grasping the existing form of arsenic in the wastewater and provides methodology support for realization of deep purification.

Description

technical field [0001] The invention belongs to the detection field, and in particular relates to a method for measuring arsenic ions using an electrochemical system. Background technique [0002] Lime-iron salt method and sulfide precipitation method are the main methods for treating arsenic-containing wastewater at present, and the arsenic removal mechanisms involved include adsorption, flocculation and co-precipitation. Although the process has been continuously optimized and improved, it is still difficult to achieve deep purification and standard discharge of arsenic. The main technical bottleneck is that arsenic is often present in wastewater as As(V)(H 3 AsO 4 、H 2 AsO 4 - 、HAsO 4 2- , AsO 4 3- ) and As(III)(H 3 AsO 3 、H 2 AsO 3 - 、HAsO 3 2- , AsO 3 3- ) and other unknown complex forms, the existence of forms and their transformation mechanisms are not clear, and it is difficult to implement regulation. [0003] Arsenic substances with known forms h...

Claims

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Application Information

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IPC IPC(8): G01N27/48
Inventor 李青竹柴立元杨锦琴王庆伟闵小波杨卫春王海鹰
Owner CENT SOUTH UNIV
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