EDI (Electro-deionization) and electro-catalytic integrated reactor and method for removing nitrate

An electrodeionization and electrocatalysis technology, applied in the field of electrochemistry, can solve problems such as low current utilization, low reaction rate, and reduced current utilization efficiency, and achieve the effects of improving current efficiency, reducing voltage drop, and reducing energy consumption

Active Publication Date: 2015-02-11
SHAANXI UNIV OF SCI & TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Reduced current utilization efficiency
[0015] 2. The most prominent problem of EDI is that it only separates and concentrates pollutants from water under the action of an electric field.
[0017] The problem with this method is mainly that the reaction rate is low, and the current utilization rate is even lower.
The biggest reason for limiting the reaction rate is that the electrocatalytic anode and cathode are placed in the same solution environment, so that a large amount of NO produced by electrocatalytic reduction 2 - , NO 2 , NO will migrate to the anode under the joint action of the electric field and the concentration gradient and the disturbance of the gas flow generated by the electrode, while the NO in the anode 2 - , NO 2 , NO is oxidized to NO 3 - , thus rendering the reaction useless
Usually handle 20mg / L NaNO 3 It takes more than 60 hours and cannot be completely removed, and the current utilization rate is less than 20%

Method used

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  • EDI (Electro-deionization) and electro-catalytic integrated reactor and method for removing nitrate
  • EDI (Electro-deionization) and electro-catalytic integrated reactor and method for removing nitrate
  • EDI (Electro-deionization) and electro-catalytic integrated reactor and method for removing nitrate

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Experimental program
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Effect test

preparation example Construction

[0084] Wherein the preparation steps of the electrocatalytic cathode electrode 31 include:

[0085] 1) First, a Pd catalyst and a Sn catalyst are loaded on the activated carbon fiber by a multi-step impregnation method to obtain Pd and Sn modified activated carbon fiber;

[0086] ① Boil the strip-shaped ACF in distilled water for more than three hours to fully desorb and regenerate to ensure that there is no impurity on the ACF carrier and that there is enough surface area in direct contact with the metal to ensure the stability of the ACF in contact with the metal and to ensure the stability of the production process. The life of the obtained catalytic electrode is guaranteed. Take it out, rinse it with distilled water, and dry it at 90-115°C for 12 hours.

[0087] ②Preparation of 300mL mass fraction of 5% ethylenediaminetetraacetic acid disodium (EDTANa 2 ) solution, soak the ACF obtained in ① for more than 12 hours to make it fully adsorb EDTANa 2 , and then dried at 90 ...

Embodiment 1

[0114] Mix D407 nitrate adsorption resin and D001 macroporous cation exchange resin at a volume ratio of 10:4 and place in fresh water chamber 1, and treat 100mg / L, 6L NaNO 3 solution, EDI runs for 300min, and NaNO is discharged 3 The concentration has been kept below 2mg / L, and the conductivity is 17us / cm, which is close to the standard of pure water. And the NaNO concentrated in the anode concentrated water chamber 3 The concentration is 735mg / L, and the conductivity has exceeded 9999us / cm. After electrocatalytic reduction for 1800min, NO 3 - The concentration has dropped to 110mg / L, Na + and OH - Combined to form NaOH, NaNO 3 The removal amount reached more than 85%.

Embodiment 2

[0116] The reactor handles 90mg / L, 6L of Mg(NO 3 ) 2 solution, EDI runs for 300min, and NaNO is discharged 3 Concentration has been maintained at 1.7mg / L or less. The conductivity is 17us / cm. Close to the standard of pure water. While the concentrated Mg(NO 3 ) 2 The concentration is 677g / L, and the conductivity has reached 8924us / cm. After electrocatalytic reduction for 1800min, NO 3 - The concentration has dropped to 96mg / L, Mg 2+ with OH - Combined to form magnesium hydroxide precipitate. The removal amount reached more than 85%.

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Abstract

The invention relates to an EDI (Electro-deionization) and electro-catalytic integrated reactor and a method for removing nitrate. Raw water containing the nitrate is conveyed to a fresh water chamber, and cations in the raw water penetrate through a first cation exchange membrane under the action of an electric field, enter a cathode pole water chamber, pass through a circulating loop formed by simultaneously connecting an anode pole water chamber and the cathode pole water chamber with a cathode/anode liquid circulating water tank respectively, enter the anode pole water chamber from the cathode pole water chamber, penetrate through a second cation exchange membrane, enter an anode concentrated water chamber, and are recycled; anions in the raw water penetrate through a first anion exchange membrane under the action of the electric field, enter the anode concentrated chamber, and are gathered with the cations, and gas is generated under the reduction action of an electro-catalytic cathode electrode and is discharged; purified water is discharged from the fresh water chamber, so that the nitrate is removed. EDI and electro-catalytic reduction are organically combined to form an integrated reactor, so that the capacity of efficiently removing the nitrate in water through the EDI is retained, the current efficiency is improved, and the reaction rate is improved.

Description

technical field [0001] The invention belongs to the field of electrochemistry, and in particular relates to an electrodeionization and electrocatalysis integrated reactor and a method for removing nitrate. Background technique [0002] Due to the irrational development and utilization of water resources, excessive fertilization of farmland and the random discharge of pollutants, the water system has been seriously polluted by nitrate and nitrite, and the safety of human drinking water has been severely tested. Humans drink water with excessive nitrate and nitrite, which can cause various diseases, such as degenerative hemoglobinemia in infants and adult cancers (stomach cancer, liver cancer, colorectal cancer, bladder cancer, ovarian cancer, non-Hodgkin lymphoma, etc.) ). The current national standard NO 3 - -N control limit is 10mg / L, and most water bodies have already exceeded this standard value. Therefore, the treatment of nitrate in water body has reached the point ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C02F1/469C02F1/467
CPCC02F1/46109C02F1/4676C02F1/4695C02F2001/46142C02F2101/163
Inventor 花莉胡阳阳马宏瑞
Owner SHAANXI UNIV OF SCI & TECH
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