Electrochemical decoloration method of direct dye wastewater

A dye wastewater, electrochemical technology, applied in chemical instruments and methods, water/sewage treatment, light water/sewage treatment, etc. Conducive to environmental protection, significant decolorization effect, and the effect of improving decolorization effect

Inactive Publication Date: 2017-12-05
MINJIANG UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Among them, metal is the earliest anode material used by humans. Although its conductivity is very good, the metal will dissolve during the electrolysis process. In this way, not only the anode material is lost, but also new impurities are added to the electrolysis process. Affect dye degradation results
Subsequently, humans used inert materials instead of metals as anodes, but the situation was not optimistic. Although inert materials did not appear to dissolve as anodes, the electrocatalytic activity was not high, which made the efficiency of wastewater treatment low, and the electrodes were prone to contamination due to pollution. Inactivate

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0014] Direct Rose Red is a naphthalene-based o-hydroxy azo dye, which is also a direct dye. Using fluorine-doped tin dioxide (FTO) conductive glass as the anode and graphite as the cathode, adjust the pH value of the dye wastewater to 7.0, control the applied voltage to 10V, and the distance between the electrode plates to 4cm, to contain 0.16g / L chloride The decolorization rate of Direct Rose Bengal (0.4g / L) solution of sodium can reach more than 95% after electrochemical degradation for 60min.

Embodiment 2

[0016] The difference between this embodiment and the above-mentioned embodiment 1 is that: when performing electrochemical degradation, the current is controlled instead of the applied voltage. By electrochemically decolorizing the direct grass yellow, adjust the pH value of the dye wastewater to 7.0, and set the applied current to 0.2A / cm 2 , the distance between the electrode plates is 3cm, after the electrochemical degradation of the direct grass yellow (0.5g / L) solution containing 2.0g / L sodium chloride for 10min, the decolorization rate of the direct grass yellow can reach more than 90%. According to the infrared spectra before and after electrochemical decolorization of grass yellow, it is speculated that part of the azo bonds and benzene rings were broken during the electrolysis process.

Embodiment 3

[0018] The difference between this embodiment and the above-mentioned embodiment 1 is that the direct orange S is electrochemically decolorized by using a platinum rod as the cathode material. When the control applied voltage is 20V, the distance between the electrode plates is 5cm, and when 0.8g / L sodium chloride is used as the electrolyte, the electrolysis of direct orange S dye solution (0.08g / L, pH 7.0) for 15min, the decolorization rate of the dye can be up to 76.1%. The degradation sequence is a first-order reaction. During the decolorization process, the azo double bond in the S structure of the direct orange is broken first, part of the naphthalene ring is destroyed, and the sulfonic acid group falls off.

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PUM

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Abstract

The invention relates to a method for decolorizing direct dye wastewater and particularly relates to an electrochemical decoloration method of direct dye wastewater. The method utilizes FTO glass as an anode material and carries out electrochemical decoloration of wastewater in an electrolytic cell. The fluorine-doped tin oxide conductive glass (FTO glass) is used as an anode material and has good light transmittance. If needed, a photocatalytic reagent can be simultaneously added to the waste liquid so as to realize photocatalytic and electrochemical decolorization at the same time so that decolorization effects are improved and energy consumption is reduced. The method has the advantages of significant decoloring effects, low chroma of the decolorized solution, good translucency and repeated use of the electrode, can realize quick decolorization of a direct dye and is conducive to environmental protection.

Description

technical field [0001] The invention relates to a decolorization method of direct dye wastewater, in particular to an electrochemical decolorization method of direct dye wastewater. Background technique [0002] In 1884, Bottiger synthesized the first direct dye—Congo Red (Congo Red) by chemical methods. Today, direct dyes have a long history of more than 100 years. Direct dyes are widely used for dyeing and printing of various textile materials. With the development of the dye industry, the environmental pollution is becoming more and more serious. Direct dye wastewater has complex components, many refractory substances, and large chroma. When it is directly discharged into the water without treatment, it will not only affect the growth of aquatic animals and plants, but also increase the content of organic matter in the water. The most serious is the dye and its presence in the water. Some derivatives produced in natural water bodies have three effects of carcinogenicity...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C02F1/461C02F1/30
CPCC02F1/30C02F1/46109C02F2001/46133
Inventor 陈毅挺李艳霞黄露娄本勇林棋
Owner MINJIANG UNIV
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