Method for zero-valent metal and carbon combination internal electrolysis catalysis reduction of nitrate nitrogen in water zero-valent metal and carbon combination

A zero-valent metal, nitrate nitrogen technology, applied in chemical instruments and methods, reduced water/sewage treatment, water pollutants, etc., can solve problems such as hindering metal reactivity, reducing reaction rate, reducing reduction efficiency, etc. The effect of high time and space efficiency, simple operation and fast restoration speed

Inactive Publication Date: 2013-07-10
RES CENT FOR ECO ENVIRONMENTAL SCI THE CHINESE ACAD OF SCI
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Among them, the simple metal reduction method is a denitrification method developed in recent years. It uses zero-valent metals as the reducing agent to directly reduce the nitrate ions in the solution to nitrogen without adding any chemicals. The reaction speed is fast and the process is simple. It is easy to operate, but the metal element reduction method has the disadvantages that the metal is easily deactivated and the reduction efficiency decreases.
For example, when zero-valent iron is used for treatment, as the reaction progresses, the metal surface is easily covered with a layer of oxide or precipitate, which hinders the metal reactivity and reduces the reaction rate.

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0026] Add powdered zero-valent zinc (150 mesh in particle size) and activated carbon powder (150 mesh in particle size) directly into water containing nitrate nitrogen with an initial concentration of 25 mg / L, wherein: the input of zero-valent zinc The dosage is 0.5g / L, the dosage of activated carbon powder is 0.8g / L, and the volume ratio of zero-valent zinc to activated carbon powder is 0.1:1; apply mechanical stirring at a stirring rate of 50rpm, react for 60 minutes, The removal rate of nitrate nitrogen can reach more than 85%, NO 2 - -N as a reaction intermediate product concentration is always at a low level (4 + -N concentration is 0.20 mg / L.

Embodiment 2

[0028] Add granular zero-valent zinc (0.2-0.5 mm in particle size) and activated carbon (0.2-0.5 mm in particle size) directly into water containing nitrate nitrogen with an initial concentration of 20 mg / L, of which: zero-valent The dosage of zinc is 6g / L, the dosage of activated carbon is 0.2g / L, and the volume ratio of zero-valent zinc to activated carbon is 5:1; apply mechanical stirring at a stirring rate of 250rpm, react for 60 minutes, and The removal rate of nitrate nitrogen can reach 87%, NO 2 - -N was not detected (4 + -N concentration was 0.14 mg / L.

Embodiment 3

[0030] Add powdered zero-valent iron (50 mesh in particle size) and activated carbon (50 mesh in particle size) directly to water containing nitrate nitrogen with an initial concentration of 30 mg / L, wherein: the addition of zero-valent iron The amount of activated carbon is 8g / L, the dosage of activated carbon is 1g / L, the volume ratio of zero-valent iron and activated carbon is 1.4:1; apply mechanical stirring at a stirring rate of 200rpm, react for 60 minutes, and the removal of nitrate nitrogen in water rate can reach 90%, NO 2 - -N was not detected (4 + -N concentration is 0.25mg / L.

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Abstract

The invention belongs to the water processing technology application field, relates to a method for removing nitrate nitrogen in water, and especially relates to a method for the zero-valent metal and carbon combination internal electrolysis catalysis reduction of a pollutant nitrate nitrogen in water. A technological principle of the method is characterized in that the reductibility of a zero-valent metal elementary substance and the internal electrolysis effect of the zero-valent metal elementary substance and conductive substances comprising active carbon and the like are utilized to accelerate the transfer of electrons in a solid-liquid phase interface, so nitrate nitrogen is rapidly reduced and removed, and the zero-valent metal can prolong the service life because of the internal electrolysis effect, thereby the reaction efficiency is improved. The method is characterized in that the granular or powdery zero-valent metal and a carbon material are directly added to or are mixed and then added to water containing nitrate nitrogen, stirring is carried out in a certain strength under reacting, and nitrate is directly reduced on the surface of the metal, and is reducibly degraded under the action of nascent state hydrogen [H] generated by an electrode reaction in the internal electrolysis process. The method has the advantages of simple operation, convenient management, less secondary pollution and high reaction time and space efficiency.

Description

technical field [0001] The invention belongs to the application field of water treatment technology, and relates to a method for removing nitrate nitrogen in water, in particular to a method for electrolytically catalytically reducing pollutant nitrate nitrogen in water in a combination of zero-valent metal and carbon. Background technique [0002] Nitrate nitrogen is one of the ubiquitous groundwater pollutants, which mainly comes from the widespread use of a large number of synthetic nitrogen fertilizers in agriculture and the illegal discharge of certain industrial wastes. In recent years, the pollution of nitrate nitrogen in groundwater in my country has become increasingly prominent, and the content of nitrate nitrogen in groundwater in some areas has reached 40 mg / L (calculated as nitrogen). The harm of nitrate in drinking water is mainly to induce hyperferrinemia. At the same time, nitrate and nitrite are converted into nitrosamines, which have carcinogenic effects. ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C02F1/461C02F1/70C02F1/58C02F101/16
Inventor 刘会娟万东锦胡承志刘锐平曲久辉
Owner RES CENT FOR ECO ENVIRONMENTAL SCI THE CHINESE ACAD OF SCI
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