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Method for electrically removing heavy metals and organic pollutants from soil or sludge

A technology for organic pollutants and heavy metals, applied in chemical instruments and methods, restoration of contaminated soil, water/sludge/sewage treatment, etc., can solve problems such as complicated operation, difficult to promote, and expensive solidification method

Inactive Publication Date: 2013-06-26
付融冰
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

SVE is especially suitable for the remediation of highly volatile organic contaminated soils, such as gasoline, benzene and tetrachlorethylene, but there are certain limitations for the removal of medium and low volatile organic pollutants: low removal efficiency , long cycle (up to several years), etc.
The solidification technology of heavy metals in sludge mainly involves cement solidification method, lime solidification method, thermoplastic solidification method, vitrification technology, self-cementation solidification technology, etc., but these methods have the following defects: (1) The pollution is greatly changed. The structure of the sludge hardens or increases the volume of the sludge, which limits the subsequent utilization of resources; (2) the partial solidification method is expensive, complicated to operate, and difficult to popularize and apply
[0018] CN1544366A discloses a method for treating heavy metals in sludge, which uses sulfide and lime as fixatives to stabilize heavy metals and reduce their leaching rate
[0034] In summary, although so far, people have developed a variety of devices and / or methods for removing heavy metals and organic pollutants in polluted soil or sludge, but these devices and / or methods also have certain deficiencies, such as The operation is cumbersome, the treatment cycle is long, the energy consumption is high, the cost is high, and it is difficult to promote, etc., especially there is still a lack of effective and easy-to-operate technical means for simultaneously removing heavy metals and organic pollutants.

Method used

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  • Method for electrically removing heavy metals and organic pollutants from soil or sludge
  • Method for electrically removing heavy metals and organic pollutants from soil or sludge
  • Method for electrically removing heavy metals and organic pollutants from soil or sludge

Examples

Experimental program
Comparison scheme
Effect test

preparation example Construction

[0083] Preparation of Reactive Material Layer

[0084] Reactive material layer 1: Nanoscale zero-valent iron active material supported by montmorillonite

[0085] with Fe 3+ solution (such as FeCl 3 , Fe(NO 3 ) 3 or Fe 2 (SO 4 ) 3 any one or more of them) to impregnate the montmorillonite so that all the cation exchange sites on the montmorillonite are covered by Fe 3+ saturated, then using NaHB 4 The reducing agent is reduced, so that the Fe 3+ reduced to zero valent iron. After this treatment, the active material of montmorillonite loaded with nano-scale zero-valent iron is obtained. The active material is attached to the outer layer of the conductive material of the rotating drum, with a thickness of 3.5 cm, and wrapped with one or several layers of dense water-permeable sealing cloth. Seal and compact.

[0086] Reaction material layer 2: made of vermiculite, pumice, Fe 2 o 3 , the active material composed of Fe

[0087] Vermiculite and pumice with a particle ...

Embodiment 1

[0098] Embodiment 1: the removal of hexavalent chromium cation in soil

[0099] The device of the present invention is used to treat the soil polluted by hexavalent chromium cations, and the content of hexavalent chromium in the soil is 352mg / kg. Among them, a voltage is applied between the closed-loop hinged track as the anode and the rotating drum as the cathode, and the voltage gradient is 2.0 V / cm.

[0100] The above-mentioned reaction material layers 1-5 were respectively used for removal treatment, and the scraped soil was collected and completely dried, and then the content of hexavalent chromium ions was measured, and the results are shown in Table 1 below.

[0101] Table 1. Changes in content of hexavalent chromium ions before and after treatment

[0102]

[0103] It can be seen that after being treated by the device and method of the present invention, the removal rate of heavy metal hexavalent chromium is very high, and the efficient removal of heavy metals is e...

Embodiment 2

[0104] Embodiment 2: the removal of heavy metal in municipal sludge

[0105]A large amount of urban sewage treated by sewage treatment plants is industrial wastewater, and the sludge obtained from industrial wastewater treatment has a high content of heavy metals. Take the municipal sludge with a mass water content of 80% from the plant and put it into a regulating chamber, and add dilute hydrochloric acid with a mass concentration of 10% to adjust the pH value to 3.0. The above-mentioned active materials 1-5 were used respectively, and the voltage gradient between the anode and the cathode was 3V / cm for treatment, and the specific results are shown in Table 2 below.

[0106] Table 2. Changes in heavy metal content before and after treatment (the content units are mg kg -1 )

[0107]

[0108] It can be seen that after being treated by the device and method of the present invention, the removal rate of several heavy metals is relatively high, which can reach the agricultur...

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Abstract

The invention provides a method for electrically removing heavy metals and organic pollutants from soil or sludge. An electric removal device is used in the method and comprises a rotary drum, a gear, an outer closed-loop hinged crawler belt and a closed-loop conveying crawler belt, wherein a conductive material covers the rotary drum, and a reaction material layer is wrapped outside the conductive material; the gear surrounds the rotary drum; the outer closed-loop hinged crawler belt is made of a conductive material and engaged on the gear to realize closed-loop operation; and the closed-loop conveying crawler belt is used for conveying soil or sludge, penetrates through the clearance between the outer closed-loop hinged crawler belt and the rotary drum and is compacted on the rotary drum. By using the device and selecting proper operating industrial parameters, the heavy metals and / or the organic pollutants can be quickly, effectively and simultaneously removed from the polluted soil or the sludge; and the method is easy and convenient to operate and high in removal efficiency, and has a good industrial application prospect.

Description

technical field [0001] The invention relates to a method for removing harmful substances from soil or sludge, in particular to an electrodynamic method for removing heavy metals and organic pollutants in soil or sludge, and belongs to the fields of soil restoration and sludge harmless treatment. Background technique [0002] my country has accumulated relatively serious soil pollution in the long-term industrialization process. For example, in recent years, in the process of rapid urbanization, a large number of factories and enterprises have been shut down and relocated, and cities have been relocated. Organic matter; another example is that due to the long-term use and residue of pesticides, a large area of ​​farmland soil is polluted by pesticides; another example is oilfield exploration, oil extraction, oil storage and transportation, and gas station leakage, which has caused soil petroleum hydrocarbon pollution.. ...severe soil pollution poses a clear threat to groundw...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): B09C1/00C02F11/00
Inventor 付融冰
Owner 付融冰