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Method for strengthening Cr(VI) electroreduction by virtue of small molecular inorganic acid

A small molecule organic acid and inorganic acid technology, applied in chemical instruments and methods, water/sludge/sewage treatment, water/sewage treatment, etc., can solve problems such as low efficiency and limit the feasibility of industrial application, and achieve electric energy Low consumption, easy to promote and use on a large scale, and the effect of adding less

Inactive Publication Date: 2016-07-20
QINGDAO TECHNOLOGICAL UNIVERSITY
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

However, in acidic solution, Cr(VI) usually mainly forms as HCrO 4 - and CrO 4 2- The negative ions exist in the form of negative ions. From the theory of electrostatic mechanics, it is difficult for these anions to be enriched on the surface of the cathode. Therefore, the efficiency of direct electrochemical reduction to remove Cr(VI) is low, which greatly limits the feasibility of its industrial application.

Method used

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  • Method for strengthening Cr(VI) electroreduction by virtue of small molecular inorganic acid
  • Method for strengthening Cr(VI) electroreduction by virtue of small molecular inorganic acid
  • Method for strengthening Cr(VI) electroreduction by virtue of small molecular inorganic acid

Examples

Experimental program
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Effect test

Embodiment 1

[0022] Add 0.5mM oxalic acid to the water body with a Cr(VI) concentration of 0.1mM (mmol / L, the same below), adjust the pH value to 3 with sulfuric acid, and use Na 2 SO 4 Adjust the conductivity of the electrolyte to about 3ms / cm, so that the mixed solution reaches 200mL, and use a low-voltage DC power supply to conduct electrolysis with a constant current I=20mA. The anode used is flake graphite, iron or platinum (1cm×1cm), and the cathode is a sheet Activated carbon fiber, glassy carbon, metal platinum or graphite (3cm×3cm), during this process, use a magnetic stirrer to stir the electrolyte to mix evenly.

[0023] Comparative Experiment 1: Add 0.5mM oxalic acid to water with a Cr(VI) concentration of 0.1mM, adjust the pH value to 3 with sulfuric acid, and use Na 2 SO 4 Adjust the conductivity of the electrolyte to about 3ms / cm, so that the mixed solution reaches 200mL. Under the condition of no electricity, use a magnetic stirrer to stir the solution to make it uniform....

Embodiment 2

[0026] Add 0.5mM citric acid to water with a Cr(VI) concentration of 0.1mM, adjust the pH value to 3 with sulfuric acid, and use Na 2 SO 4 Adjust the conductivity of the electrolyte to about 3ms / cm, so that the mixed solution reaches 200mL, and use a low-voltage DC power supply to conduct electrolysis with a constant current I=20mA. The anode used is flake graphite, iron or platinum (1cm×1cm), and the cathode is a sheet Activated carbon fiber, glassy carbon, metal platinum or graphite (3cm×3cm), during this process, use a magnetic stirrer to stir the electrolyte to mix evenly.

[0027] Comparative Experiment 1: Add 0.5mM citric acid to water with a Cr(VI) concentration of 0.1mM, adjust the pH value to 3 with sulfuric acid, and use Na 2 SO 4 Adjust the conductivity of the electrolyte to about 3ms / cm, so that the mixed solution reaches 200mL. Under the condition of no electricity, use a magnetic stirrer to stir the solution to make it uniform.

[0028] Comparative experiment ...

Embodiment 3

[0030] Add 1 mM malic acid to the water body with Cr(VI) concentration of 0.1 mM, adjust the pH value to 3 with sulfuric acid, and use Na 2 SO 4 Adjust the conductivity of the electrolyte to about 3ms / cm, so that the mixed solution reaches 200mL, and use a low-voltage DC power supply to conduct electrolysis with a constant current I=20mA. The anode used is flake graphite, iron or platinum (1cm×1cm), and the cathode is a sheet Activated carbon fiber, glassy carbon, metal platinum or graphite (3cm×3cm), during this process, use a magnetic stirrer to stir the electrolyte to mix evenly.

[0031] Comparative experiment 1: Add 1 mM malic acid to water with a Cr(VI) concentration of 0.1 mM, adjust the pH value to 3 with sulfuric acid, and use Na 2 SO 4 Adjust the conductivity of the electrolyte to about 3ms / cm, so that the mixed solution reaches 200mL. Under the condition of no electricity, use a magnetic stirrer to stir the solution to make it uniform.

[0032]Comparative experim...

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Abstract

The invention relates to the field of heavy metal pollution remediation, in particular to a method for strengthening Cr(VI) electroreduction conversion by virtue of an environmentally-compatible small molecular inorganic acid with a specific chemical functional group. The method comprises the following steps: adding the small molecular inorganic acid into a Cr(VI)-containing wastewater solution to be treated under normal temperature and normal pressure, adding an inorganic acid to regulate the pH value, and reducing Cr(VI) into Cr(III) under the action of low-voltage direct current by adopting an electrolytic method. According to the method, hypertoxic Cr(VI) is efficiently and rapidly reduced into Cr(III) under the synergistic effect of the small molecular organic acid and electrolysis, the small molecular organic acid, as a catalyst, can also serve as an electron donor to participate in reductive conversion of Cr(VI) in the process, and in the process, a small amount of chemical reagent is added, no secondary pollution is produced, fewer precipitates and sludge are produced, and the power consumption is low.

Description

technical field [0001] The invention relates to the field of remediation of heavy metal pollution, in particular to a method for strengthening Cr(VI) electroreduction transformation by using an environmentally compatible small molecule organic acid with specific chemical functional groups. Background technique [0002] Heavy metal chromium compounds are widely used in electroplating, metallurgy, printing and dyeing, tanning, wood preservation and other industries. Therefore, the leakage and unreasonable discharge of chromium-containing wastewater are likely to bring serious harm to the safety of the water environment and human beings themselves. Chromium usually exists in the form of Cr(VI) and Cr(III) in water, and the different forms of chromium ion show great differences in physicochemical properties, chemical activity and biological toxicity. For example, Cr(III) is an essential trace element for the human body, and its migration ability in natural water environment is w...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C02F1/461C02F1/68C02F101/22
CPCC02F1/461C02F1/68C02F2101/22
Inventor 江波信帅帅高荔刘奕捷毕学军罗思义
Owner QINGDAO TECHNOLOGICAL UNIVERSITY
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