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Water and waste water purification method for improving reactivity of zero-valent iron through magnetic field pretreatment

A reactive, wastewater purification technology for water and wastewater treatment

Inactive Publication Date: 2013-10-02
TONGJI UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0005] The purpose of the present invention is to provide a method for improving the reactivity of zero-valent iron by magnetic field pretreatment in order to overcome the defects of the two common methods for improving the reactivity of zero-valent iron (preparation of bimetallic or nano-iron)

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  • Water and waste water purification method for improving reactivity of zero-valent iron through magnetic field pretreatment

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Effect test

Embodiment 1

[0020] A method for magnetic field pretreatment in this embodiment to improve the reactivity of zero-valent iron comprises the following steps:

[0021] (1) Pretreat zero-valent iron in a magnetic field, the magnetic field used is an alternating magnetic field, the maximum strength of the magnetic field is about 30 mT, the frequency is about 0.01 Hz, and the pretreatment time is 5 minutes;

[0022] (2) Add zero-valent iron pretreated by magnetic field and untreated zero-valent iron into the Se(IV)-containing solution. The reactor adopts a complete mixing type, and the initial concentration of Se(IV) is 5.0 mg / L. pH=6.0, zero-valent iron concentration 1.0 g / L. see results figure 1 . Depend on figure 1 It can be seen that magnetic field pretreatment can greatly increase the reaction rate between zero-valent iron and Se(IV), and shorten the reaction time. The zero-valent iron pretreated by magnetic field can remove all Se(IV) within 60 minutes, but the zero-valent iron withou...

Embodiment 2

[0024] A method for magnetic field pretreatment in this embodiment to improve the reactivity of zero-valent iron comprises the following steps:

[0025] (1) Pretreat zero-valent iron in a magnetic field, the magnetic field used is a constant magnetic field, the magnetic field strength is about 70 mT, and the pretreatment time is 3 minutes;

[0026] (2) Add zero-valent iron pretreated by magnetic field and untreated zero-valent iron into the Cr(VI)-containing solution respectively. The reactor adopts a complete mixing type, and the initial concentration of Cr(VI) is 5.0 mg / L. pH=5.0, zero-valent iron concentration 0.5 g / L. Magnetic field pretreatment can greatly increase the reaction rate between zero-valent iron and Cr(VI), and shorten the reaction time. The zero-valent iron pretreated by magnetic field can remove all Cr(VI) within 70 minutes, but the zero-valent iron without magnetic field pretreatment can only remove 98% of Cr(VI) in 180 minutes.

Embodiment 3

[0028] A method for magnetic field pretreatment in this embodiment to improve the reactivity of zero-valent iron comprises the following steps:

[0029] (1) Pretreat zero-valent iron in a magnetic field, the magnetic field used is a pulsed magnetic field, the magnetic field strength is about 0-50 mT, the frequency is about 1 Hz, and the pretreatment time is 8 minutes;

[0030] (2) Add zero-valent iron pretreated by a magnetic field and untreated zero-valent iron into the solution containing Se(VI) respectively. The reactor adopts a complete mixing type, and the initial concentration of Se(VI) is 40.0 mg / L. pH=6.0, zero-valent iron concentration 1.0 g / L. Magnetic field pretreatment can greatly increase the reaction rate between zero-valent iron and Se(VI), and shorten the reaction time. The zero-valent iron pretreated by magnetic field can remove 95% of Se(VI) within 90 minutes, but the zero-valent iron without magnetic field pretreatment can only remove 20% of Se(VI) in 1440 ...

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Abstract

The invention belongs to the technical field of water and waste water treatment, and relates to a water and waste water purification method for improving reactivity of zero-valent iron through magnetic field pretreatment. The method is characterized by pretreating the zero-valent iron by utilizing the magnetic field, and adding the pretreated zero-valent iron into a relevant reactor for purifying the water or waste water. The method aims at the application of the zero-valent iron in environment pollution improvement. The zero-valent iron is pretreated in the magnetic field, and a passive film on the surface of the zero-valent iron is destroyed, so that the corrosion rate of the zero-valent iron can be accelerated, and the removal rate of the contaminant can be improved. The method can be used not only for improving the reactivity of unused zero-valent iron but also for improving the reactivity of used zero-valent iron with the passive film on the surface. Compared with the prior art, the method is simple to use, does not consume any chemical substance, and is environment-friendly and energy-saving, after the reaction, no toxic metal ions are left, and the method has no ecotoxicity.

Description

technical field [0001] The invention belongs to the technical field of water and waste water treatment, and relates to a water and waste water purification method for improving the reactivity of zero-valent iron through magnetic field pretreatment. Background technique [0002] Zero-valent iron is cheap, environmentally friendly and widely used in the removal of environmental pollutants. Zero-valent iron is prone to corrosion reactions in water, that is, zero-valent iron and oxidants in water (O 2 、H + or H 2 O) An electrochemical reaction occurs, and the anode reaction is that iron loses electrons and transforms into soluble Fe 2+ Or insoluble ferric hydroxide, the accompanying cathodic reaction is a reduction reaction. During the corrosion process of zero-valent iron, Fe 2+ (aq) , Fe 3+ (aq) 、H 2 And various precipitates such as Fe(OH) 2 , Fe(OH) 3 , Fe 3 o 4 , Fe 2 o 3 , FeOOH, patina and other corrosion products. It is these corrosion reactions and corros...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C02F1/46
Inventor 关小红孙武冯翩李佳玲李晓艳
Owner TONGJI UNIV
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