LU502204B1 - Method for removing high-valent chromium in wastewater - Google Patents

Method for removing high-valent chromium in wastewater Download PDF

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Publication number
LU502204B1
LU502204B1 LU502204A LU502204A LU502204B1 LU 502204 B1 LU502204 B1 LU 502204B1 LU 502204 A LU502204 A LU 502204A LU 502204 A LU502204 A LU 502204A LU 502204 B1 LU502204 B1 LU 502204B1
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LU
Luxembourg
Prior art keywords
wastewater
chromium
electrode
removing high
electrolysis
Prior art date
Application number
LU502204A
Other languages
German (de)
Inventor
Hao Peng
Original Assignee
Univ Yangtze Normal
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Publication date
Application filed by Univ Yangtze Normal filed Critical Univ Yangtze Normal
Priority to LU502204A priority Critical patent/LU502204B1/en
Application granted granted Critical
Publication of LU502204B1 publication Critical patent/LU502204B1/en

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Classifications

    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F9/00—Multistage treatment of water, waste water or sewage
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F1/00—Treatment of water, waste water, or sewage
    • C02F1/46—Treatment of water, waste water, or sewage by electrochemical methods
    • C02F1/461—Treatment of water, waste water, or sewage by electrochemical methods by electrolysis
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F1/00—Treatment of water, waste water, or sewage
    • C02F1/46—Treatment of water, waste water, or sewage by electrochemical methods
    • C02F1/461—Treatment of water, waste water, or sewage by electrochemical methods by electrolysis
    • C02F1/46104—Devices therefor; Their operating or servicing
    • C02F1/46109—Electrodes
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F1/00—Treatment of water, waste water, or sewage
    • C02F1/66—Treatment of water, waste water, or sewage by neutralisation; pH adjustment
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F11/00—Treatment of sludge; Devices therefor
    • C02F11/12—Treatment of sludge; Devices therefor by de-watering, drying or thickening
    • C02F11/121—Treatment of sludge; Devices therefor by de-watering, drying or thickening by mechanical de-watering
    • C02F11/122—Treatment of sludge; Devices therefor by de-watering, drying or thickening by mechanical de-watering using filter presses
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F1/00—Treatment of water, waste water, or sewage
    • C02F1/46—Treatment of water, waste water, or sewage by electrochemical methods
    • C02F1/461—Treatment of water, waste water, or sewage by electrochemical methods by electrolysis
    • C02F1/46104—Devices therefor; Their operating or servicing
    • C02F1/46109—Electrodes
    • C02F2001/46133—Electrodes characterised by the material
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F2101/00—Nature of the contaminant
    • C02F2101/10—Inorganic compounds
    • C02F2101/20—Heavy metals or heavy metal compounds
    • C02F2101/22—Chromium or chromium compounds, e.g. chromates

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  • Life Sciences & Earth Sciences (AREA)
  • Hydrology & Water Resources (AREA)
  • Engineering & Computer Science (AREA)
  • Environmental & Geological Engineering (AREA)
  • Water Supply & Treatment (AREA)
  • Chemical & Material Sciences (AREA)
  • Organic Chemistry (AREA)
  • Removal Of Specific Substances (AREA)
  • Treatment Of Water By Oxidation Or Reduction (AREA)

Abstract

A method for removing high-valent chromium in wastewater comprises the following steps: S1, adding a small amount of sulfuric acid into wastewater to adjust the pH of wastewater to 0-4.0; S2, inserting the cleaned electrode into the waste water tank, turning on the power supply, adjusting the voltage, electrolyzing for 10-60 min at the current density of the electrode of 0.01 A/cm2 - 0.05 A/cm2 and the temperature of 30-70 degree Celsius, and stopping the electrolysis; S3, adding a proper amount of sodium hydroxide into the wastewater after electrolysis, stirring and reacting for 30-90 min, and carrying out pressure filtration to obtain chromium-free wastewater and chromium hydroxide slag; and S4, discharging wastewater containing no chromium after treatment, simply treating chromium hydroxide slag and recycling as chromium resource.

Description

DESCRIPTION LU502204 METHOD FOR REMOVING HIGH-VALENT CHROMIUM IN WASTEWATER
TECHNICAL FIELD The invention relates to the field of wastewater treatment, in particular to a method for removing high-valent chromium in wastewater.
BACKGROUND Chromium is one of the essential trace elements for animals and human bodies, but a large amount of chromium entering the environment will do great harm to human bodies, plants and animals. With the rapid development of industry, chromium pollution is becoming more and more serious, mainly involving metallurgy, chemical industry, agriculture, medicine and other fields. For a long time, the treatment of chromium-containing wastewater is a thorny environmental problem and an important research field in industrial wastewater treatment. In the waste liquid containing chromium, chromium mainly exists in the form of Cr(IIT) and Cr(VI), in which Cr(II) is more stable than Cr(VI) and its toxicity is relatively small. Therefore, at present, the main treatment method is to reduce Cr(VI) to Cr(IIT) before subsequent treatment. Chemical reduction precipitation is one of the most traditional methods, which has the advantages of mature technology, simple operation, low equipment investment and low operating cost, but it will consume a lot of reducing agents, acid-base solutions and produce a lot of chromium-containing sludge.
SUMMARY To solve the above problems, the present invention provides a method for removing high-valent chromium from wastewater, which does not generate a large amount of waste residue when reducing hexavalent chromium, and the obtained chromium hydroxide residue can be utilized as a resource.
To achieve the above purpose, the technical scheme of the invention is as follows: A method for removing high-valent chromium in wastewater comprises the following steps: S1, adding a small amount of sulfuric acid into wastewater to adjust the pH of wastewater to 0-4.0;
S2, inserting the cleaned electrode into the waste water tank, turning on the power supply502204 adjusting the voltage, electrolyzing for 10-60 min at the current density of the electrode of 0.01 A/cm? - 0.05 A/cm? and the temperature of 30-70°C, and stopping the electrolysis; S3, adding a proper amount of sodium hydroxide into the wastewater after electrolysis, stirring and reacting for 30-90 min, and carrying out pressure filtration to obtain chromium-free wastewater and chromium hydroxide slag; and S4, discharging wastewater containing no chromium after treatment, simply treating chromium hydroxide slag and recycling as chromium resource.
Further, in S2, the electrode is a quaternary alloy electrode or a stainless steel electrode.
Further, in S3, the amount ratio of sodium hydroxide to chromium ions in wastewater is 3:1 (i.e. the mass ratio is 120:52) In the above scheme, electric energy, a clean energy source, is used to replace the traditional chemical reductant, which can efficiently reduce hexavalent chromium while reducing the discharge of chromium-containing sludge, and realize the resource reuse of chromium.
DESCRIPTION OF THE INVENTION The present invention will be described in detail with reference to the following specific examples. The following examples will help those skilled in the art to further understand the present invention, but will not limit the present invention in any way. It should be pointed out that for those skilled in the art, without departing from the concept of the present invention, several modifications and improvements can be made, all of which belong to the scope of protection of the present invention.
Embodiment 1 A method for removing high-valent chromium in wastewater comprises the following steps: S1, adding a small amount of sulfuric acid into wastewater to adjust the pH of wastewater to 0-4.0; S2, inserting the cleaned stainless steel electrode into the waste water tank, turning on the power supply, adjusting the voltage, electrolyzing for 60 min at the current density of the electrode of 0.01 A/cm? and the temperature of 70°C, and stopping the electrolysis; S3, adding a proper amount of sodium hydroxide into the wastewater after electrolysis, stirring and reacting for 30-90 min, and carrying out pressure filtration to obtain chromium-free wastewater and chromium hydroxide slag, where the molar ratio of sodium hydroxide t&J502204 chromium ions in wastewater is 3:1; and S4, discharging wastewater containing no chromium after treatment, simply treating chromium hydroxide slag and recycling as chromium resource.
Embodiment 2 A method for removing high-valent chromium in wastewater comprises the following steps: S1, adding a small amount of sulfuric acid into wastewater to adjust the pH of wastewater to 0-4.0; S2, inserting the cleaned quaternary alloy electrode into the waste water tank, turning on the power supply, adjusting the voltage, electrolyzing for 10 min at the current density of the electrode of 0.05 A/cm? and the temperature of 30°C, and stopping the electrolysis; S3, adding a proper amount of sodium hydroxide into the wastewater after electrolysis, stirring and reacting for 30-90 min, and carrying out pressure filtration to obtain chromium-free wastewater and chromium hydroxide slag, where the molar ratio of sodium hydroxide to chromium ions in wastewater is 3:1; and S4, discharging wastewater containing no chromium after treatment, simply treating chromium hydroxide slag and recycling as chromium resource.
Embodiment 3 A method for removing high-valent chromium in wastewater comprises the following steps: S1, adding a small amount of sulfuric acid into wastewater to adjust the pH of wastewater to 0-4.0; S2, inserting the cleaned stainless steel electrode into the waste water tank, turning on the power supply, adjusting the voltage, electrolyzing for 35 min at the current density of the electrode of 0.03 A/cm? and the temperature of 50°C, and stopping the electrolysis; S3, adding a proper amount of sodium hydroxide into the wastewater after electrolysis, stirring and reacting for 30-90 min, and carrying out pressure filtration to obtain chromium-free wastewater and chromium hydroxide slag, where the molar ratio of sodium hydroxide to chromium ions in wastewater is 3:1; and S4, discharging wastewater containing no chromium after treatment, simply treating chromium hydroxide slag and recycling as chromium resource.
The specific embodiments of the present invention have been described above.
It should b&J502204 understood that the present invention 1s not limited to the above specific embodiments, and those skilled in the art can make various changes or modifications within the scope of the claims, which will not affect the essential content of the present invention.
Without conflict, the embodiments of the present application and the features in the embodiments can be arbitrarily combined with each other.

Claims (3)

  1. CLAIMS LU502204 I. A method for removing high-valent chromium in wastewater, characterized by comprising the following steps: S1, adding a small amount of sulfuric acid into wastewater to adjust the pH of wastewater to 0-4.0; S2, inserting the cleaned electrode into the waste water tank, turning on the power supply, adjusting the voltage, electrolyzing for 10-60 min at the current density of the electrode of 0.01 A/cm? - 0.05 A/cm? and the temperature of 30-70°C, and stopping the electrolysis; S3, adding a proper amount of sodium hydroxide into the wastewater after electrolysis, stirring and reacting for 30-90 min, and carrying out pressure filtration to obtain chromium-free wastewater and chromium hydroxide slag; and S4, discharging wastewater containing no chromium after treatment, simply treating chromium hydroxide slag and recycling as chromium resource.
  2. 2. The method for removing high-valent chromium in wastewater according to claim 1, characterized in that in S2, the electrode is a quaternary alloy electrode or a stainless steel electrode.
  3. 3. The method for removing high-valent chromium in wastewater according to claim 1, characterized in that in S3, the amount ratio of sodium hydroxide to chromium ions in wastewater is 3:1.
LU502204A 2022-05-31 2022-05-31 Method for removing high-valent chromium in wastewater LU502204B1 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
LU502204A LU502204B1 (en) 2022-05-31 2022-05-31 Method for removing high-valent chromium in wastewater

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
LU502204A LU502204B1 (en) 2022-05-31 2022-05-31 Method for removing high-valent chromium in wastewater

Publications (1)

Publication Number Publication Date
LU502204B1 true LU502204B1 (en) 2022-12-01

Family

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Family Applications (1)

Application Number Title Priority Date Filing Date
LU502204A LU502204B1 (en) 2022-05-31 2022-05-31 Method for removing high-valent chromium in wastewater

Country Status (1)

Country Link
LU (1) LU502204B1 (en)

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