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A method of using different complexing agents to assist electrochemical removal of Cr3+ in water

A complexing agent and water removal technology, applied in chemical instruments and methods, electrochemical water/sewage treatment, water pollutants, etc., can solve the problems of small adsorption capacity, secondary pollution, and large power consumption of electrocoagulation. achieve an easy-to-remove effect

Active Publication Date: 2019-04-05
FUJIAN NORMAL UNIV
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  • Abstract
  • Description
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  • Application Information

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Problems solved by technology

[0003] Currently, Cr in aqueous solution 3+ The removal methods mainly include adsorption, electrocoagulation, membrane separation, hydroxide precipitation, etc., but there are some unavoidable shortcomings.
The adsorption method has problems such as slow adsorption of pollutants, small adsorption capacity, and is easily affected by environmental factors; electrocoagulation has problems such as large power consumption, high energy consumption, and high turbidity of the effluent; membrane separation method is effective in treating low-concentration wastewater. Concentration polarization is prone to occur when the membrane is fouled, the energy consumption increases, and the effluent quality decreases.
Among various treatment methods, the hydroxide precipitation method is the most commonly used method, but the hydroxide precipitation method will produce a large amount of sludge, which requires secondary treatment. At the same time, according to the research of Erdem et al., the hydroxide precipitation sludge The chromium element in the sludge is easily dissolved from the sedimentation sludge, forming secondary pollution

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  • A method of using different complexing agents to assist electrochemical removal of Cr3+ in water

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Experimental program
Comparison scheme
Effect test

Embodiment 1

[0021] Removal of Cr by Formic Acid Assisted Single-walled Carbon Nanotube Stainless Steel Mesh Electrode 3+ waste water:

[0022] 200mL containing Cr 3+ Wastewater (containing Cr 3+ : 6.13mg / L) into the reaction chamber, add 2g of sodium sulfate, use single-walled carbon nanotube-modified stainless steel mesh electrode as the cathode, titanium mesh as the anode, control the pH of the reaction chamber to 4.0, and maintain the current density at 2 mA / cm 2 , the amount of formic acid added is 0.2452mg. The processing time is 210min. Contains Cr 3+ After the wastewater is treated, measure and calculate Cr with a spectrophotometer 3+ Removal rate, indicating that Cr 3+ The concentration decreased to 1.43mg / L, and the removal rate was 76.7%.

[0023] The Cr-containing 3+ Wastewater is simulated wastewater.

Embodiment 2

[0025] Acetic acid-assisted single-wall carbon nanotube stainless steel mesh electrode to remove Cr 3+ waste water:

[0026] 200mL containing Cr 3+ Wastewater (containing Cr 3+ : 6.35mg / L) into the reaction chamber, add 1.6g of sodium sulfate, use single-walled carbon nanotube-modified stainless steel mesh electrode as the cathode, and titanium mesh as the anode, control the pH of the reaction chamber to 3.5, and maintain the current density at 2.2 mA / cm 2 . The amount of acetic acid added is 0.2540 mg. The chemical treatment time is 240min. Contains Cr 3+ After the wastewater is treated, measure and calculate Cr with a spectrophotometer 3+ Removal rate, indicating that Cr 3+ The concentration was reduced to 0.96mg / L, and the removal rate was 84.9%.

[0027] The Cr-containing 3+ Wastewater is simulated wastewater.

Embodiment 3

[0029] Oxalic acid-assisted single-wall carbon nanotube stainless steel mesh electrode to remove Cr 3+ waste water:

[0030] 200mL containing Cr 3+ Wastewater (containing Cr 3+ : 6.49mg / L) into the reaction chamber, add 2g of sodium sulfate, use single-walled carbon nanotube-modified stainless steel mesh electrode as the cathode, titanium mesh as the anode, control the pH of the reaction chamber to 2.5, and maintain the current density at 2.5 mA / cm 2 . The amount of oxalic acid added is 0.2596mg. The chemical treatment time is 240min. Contains Cr 3+ After the wastewater is treated, measure and calculate Cr with a spectrophotometer 3+ Removal rate, indicating that Cr 3+ The concentration was reduced to 0.51mg / L, and the removal rate was 92.1%.

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Abstract

The invention relates to a method for removing Cr3+ in water by means of different complexing agents with assistance of electrochemistry. Cr3+ containing wastewater is introduced into a reaction chamber, a certain number of complexing agents and supporting electrolyte sodium sulfate are added, a stainless steel mesh modified by a single-wall nanometer tube is adopted as a cathode, a titanium net is adopted as an anode, the pH of the reaction chamber is adjusted to a certain value, power-on treatment is performed for a certain period of time at the certain current density, and then a spectrophotometer is used for measuring and calculating the Cr3+ removal rate to obtain wastewater reaching the standard to be drained. The method has the advantages that different types of complexing agents are added, so that the form of Cr3+ in a water solution is changed, and Cr3+ can be removed easily; the reaction power consumption is lowered while the Cr3+ removal rate is increased.

Description

technical field [0001] This patent relates to the technical field of wastewater treatment, in particular to a method of using different complexing agents to assist electrochemical removal of trivalent chromium (Cr 3+ )method. Background technique [0002] Chromium is widely used in industries such as electroplating, metal processing, pigments, leather processing, chemical manufacturing, electronic equipment and the catalytic industry. There are a large amount of Cr in many industries every day 6+ and Cr 3+ Acidic wastewater is generated. With people's interest in Cr 6+ Toxicity awareness, Cr 6+ The use of chromium has been strictly controlled, and Cr in chromium-containing wastewater 3+ There are still a large number and the proportion is increasing. Although Cr 3+ less toxic than Cr 6+ Strong, but in the natural environment, Cr 6+ and Cr 3+ Interconversion phenomenon, Cr 3+ It is a great potential threat to human beings and the natural environment, so it is neces...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C02F1/46C02F101/22
CPCC02F1/46C02F2101/22
Inventor 刘耀兴陈佳辉陈日耀
Owner FUJIAN NORMAL UNIV