CN109399765B - Method for electrochemically degrading azo dye wastewater by using amorphous alloy - Google Patents

Abstract

The invention discloses a method for electrochemically degrading azo dye wastewater by using amorphous alloy. According to the method, Zr-based, Cu-based, Fe-based, Al-based, Co-based, Ni-based and Mg-based amorphous alloy strips are used as working electrodes, pure Ti or Pt electrodes are used as counter electrodes to form an electrochemical system, an azo dye solution to be degraded is used as electrolyte, and electrochemical degradation is carried out on azo dye wastewater in a constant-potential square wave or potentiodynamic scanning mode by using an electrochemical method. The electrochemical method for rapidly degrading the azo dye takes the amorphous alloy strip as the working electrode, has high degradation rate and high degradation efficiency on the azo dye, achieves the degradation efficiency of more than 90 percent, has thorough color fading, and has wide application prospect in the field of organic dye degradation.

Description

Method for electrochemically degrading azo dye wastewater by using amorphous alloy

Technical Field

The invention belongs to the field of organic dye degradation, and relates to a method for electrochemically degrading azo dyes by using amorphous alloys.

Background

The dye waste water discharged from textile, paper-making, leather, printing and other industries causes serious environmental pollution. The proportion of the azo dye in the dye is about 50 percent. Therefore, the method has very important practical significance for economically and efficiently treating the wastewater containing the azo dyes.

The general methods for degrading azo dyes in wastewater can be classified into physical, biological and chemical methods according to the components, properties and treatment indexes of the wastewater. The activated carbon adsorption process is a conventional physical process. The biological method is a sewage treatment technology for degrading and removing organic pollutants in sewage by utilizing the metabolism of microorganisms, and has the limitation that only certain special toxic azo dyes can be degraded and cannot act in a complex environment containing various chemical substances. The chemical method comprises an oxidation method, an electrolysis method, a coagulation method and an electrochemical method, wherein the electrochemistry comprises a micro-electrolysis method, a chemical modification electrode method and the like, the micro-electrolysis method is limited by electrode materials (Luyong et al, bimetallic electrolysis pretreatment coking wastewater [ J ]. chemical and biological engineering, 2014, 31(5)63-65.), and the chemical modification electrode method has lower degradation efficiency (Tangrong, catalytic purification research on nitrite ions by polyaniline modified electrodes [ J ]. mathematical and chemical research, 2014, 2: 193-196.).

Disclosure of Invention

The invention aims to provide a method for quickly and thoroughly degrading azo dye wastewater by using amorphous alloy electrochemistry.

The technical scheme for realizing the aim of the invention is as follows:

the method for electrochemically degrading azo dye wastewater by using the amorphous alloy comprises the following steps:

step 1, preparing a master alloy by adopting electric arc melting or induction melting of high-purity metal according to a ratio;

step 2, heating the mother alloy to a molten state, spraying molten alloy liquid by using high-purity argon by adopting a single copper roller melt-spinning method, and quickly solidifying the molten alloy liquid on a copper roller rotating at the revolution number of more than 2500r/min to obtain an amorphous alloy strip;

step 3, forming an electrochemical system by using an electrochemical method and taking the amorphous alloy strip as a working electrode and a pure Ti or Pt electrode as a counter electrode;

and 4, using an electrochemical method, taking the azo dye solution to be degraded as an electrolyte, and using a test method of potentiodynamic scanning with a potentiostatic range of +/-1V to +/-2V, a period of 3-5 of constant-potential square waves or a scanning potentiostatic range of-0.1-2V and a scanning rate of 1 mV/s-2 mV/s.

The amorphous alloy can be Zr-based amorphous alloy with the atomic ratio of 50-70, 50-80, 73-85, 80-94, 40-80 and 50-80.

The invention provides an electrochemical method for rapidly degrading azo dyes for the first time, which takes an amorphous alloy strip as a working electrode, has high degradation rate and high degradation efficiency on azo dyes, achieves the degradation efficiency of more than 90 percent, has thorough color fading and has wide application prospect in the field of organic dye degradation.

Drawings

Figure 1 is the XRD pattern of example 1.

FIG. 2 is an electrochemical diagram of example 1.

FIG. 3 is an electrochemical diagram of example 2.

FIG. 4 is a UV spectrum of example 2.

FIG. 5 is a UV spectrum of a comparative example.

Detailed Description

Example 1

With Zr₅₆Al₁₆Co₂₈As the starting alloy components, a mixture of raw materials of 99.99% Zr, 99.99% Al and 99.99% Co in the purity required for the starting alloy was placed in a crucible of an arc melting furnace. Firstly, the furnace chamber is vacuumized to ensure that the vacuum degree in the furnace chamber is 5 multiplied by 10^-3Pa, and then filling argon, thereby ensuring that the alloy smelting can be carried out uniformly in the atmosphere protection of inert gas. In order to ensure that the alloy can be uniformly mixed, each alloy ingot is repeatedly smelted for 3 to 4 times.

Putting 4-5g of smelted mother alloy into a quartz tube, putting the quartz tube into melt-spinning equipment, melting the alloy through induction heating, and finally spraying the molten alloy onto a copper roller rotating at high speed by using high-pressure argon to form Zr with the thickness of 20 mu m and the width of 5mm₅₆Al₁₆Co₂₈Amorphous thin bands and characterized by XRD.

Using an electrochemical workstation with Zr₅₆Al₁₆Co₂₈The amorphous alloy strip is used as a working electrode, and a pure Ti electrode or a Pt electrode is used as a counter electrode to form an electrochemical system.

At normal temperature, an electrochemical square wave method is utilized, the design voltage is +/-2V relative to the open-circuit potential, the period is 2min each time, and the period number is 5.

After the electrochemical reaction is finished, filtering the product after the reaction by using filter paper to obtain a clear solution.

FIG. 1 shows Zr₅₆Al₁₆Co₂₈XRD pattern of amorphous alloy, from which it can be seen that the XRD curve of quenched ribbon sample has one in the vicinity of 37 ° 2 thetaThe amorphous alloy has a typical wide and diffuse scattering peak and no obvious crystalline phase diffraction peak, so that the sample has a single amorphous structural characteristic, namely, the amorphous alloy is obtained.

Fig. 2(a) (b) is a square wave plot of the set voltage of ± 2V in two different azo dyes, acid orange and direct blue solutions, from which it can be seen that the current switches between 0.07A and-0.02A, with both positive and negative voltages applied for 1min per cycle and a cycle number of 5.

FIG. 4 is a UV spectrum of azo dye degradation using electrochemical method under the same conditions, which shows that the azo dye degradation effect is complete.

Example 2

Zr was obtained in the same manner as in example 1₅₆Al₁₆Co₂₈The amorphous strips constitute the electrode system.

At normal temperature, a potentiodynamic scanning method is utilized, the design parameter is-0.1V-2V relative to the open circuit potential, and the scanning speed is 1 mv/s.

After the electrochemical reaction is finished, filtering the product after the reaction by using filter paper to obtain a clear solution.

FIG. 3(a) (b) is a graph of zeta potential scanning of two different azo dye solutions, from which it can be seen that the self-etching potentials of the curves are-0.04V and-0.12V, respectively, and the amorphous alloy is in a reactive dissolved state in the two dye solutions.

Fig. 4 is an ultraviolet spectrogram of azo dyes degraded under the same conditions by using an electrochemical method, and it can be seen that absorption peaks of two azo dye solutions respectively disappear after the degradation by using a square wave method and a potentiodynamic potential scanning method, the color completely fades, and the degradation effect is good.

Example 3

This example is substantially the same as example 1, except that the amorphous alloys used were Cu, respectively₄₅Zr₄₈Al₇、 Mg₆₈Zn₂₈Ca₄Method of using electrochemical square wave, in which Cu₄₅Zr₄₈Al₇Degrading by an electrochemical square wave method to generate purple precipitate, and filtering to obtain a clear solution; mg (magnesium)₆₈Zn₂₈Ca₄And (3) degrading by an electrochemical square wave method to generate a little white precipitate, and filtering to obtain a clear solution.

Comparative example 1

Zr was obtained in the same manner as in example 1₅₆Al₁₆Co₂₈The amorphous strips constitute the electrode system.

At normal temperature, by using an electrochemical square wave method, the design voltage is respectively +/-0.5V and +/-1V relative to the open circuit potential, each period is 2min, and the period number is 5.

After the electrochemical reaction is finished, filtering the product after the reaction by using filter paper to obtain a clear solution. FIG. 5 is a UV spectrum of an azo dye of acid orange II degraded by electrochemical square wave method with design voltage of 0.5V or 1V relative to open circuit potential, showing that the absorption peak of azo dye solution still exists when the design voltage parameter is 0.5V or 1V vs 2V, and the degradation effect is poor.

Claims (2)

1. The method for electrochemically degrading azo dye wastewater by using the amorphous alloy is characterized by comprising the following steps of:

step 1, preparing a master alloy by adopting electric arc melting or induction melting of high-purity metal according to a ratio;

step 2, heating the mother alloy to a molten state, spraying molten alloy liquid by using high-purity argon by adopting a single copper roller melt spinning method, and quickly solidifying the molten alloy liquid on a copper roller rotating at the revolution number of more than 2500r/min to obtain an amorphous alloy strip, wherein the amorphous alloy is Zr₅₆Al₁₆Co₂₈Amorphous alloy, Cu₄₅Zr₄₈Al₇Or Mg₆₈Zn₂₈Ca₄；

Step 3, forming an electrochemical system by using an electrochemical method and taking the amorphous alloy strip as a working electrode and a pure Ti or Pt electrode as a counter electrode;

and 4, using an electrochemical method, taking the azo dye solution to be degraded as an electrolyte, and using a constant-potential square wave with a potential range of +/-2V and a period of 5 as a test method.

2. The method for electrochemically degrading azo dye wastewater by using the amorphous alloy is characterized by comprising the following steps of:

step 1, preparing a master alloy by adopting electric arc melting or induction melting of high-purity metal according to a ratio;

step 2, heating the mother alloy to a molten state, spraying molten alloy liquid by using high-purity argon by adopting a single copper roller melt spinning method, and quickly solidifying the molten alloy liquid on a copper roller rotating at the revolution number of more than 2500r/min to obtain an amorphous alloy strip, wherein the amorphous alloy is Zr₅₆Al₁₆Co₂₈Amorphous alloy;

step 3, forming an electrochemical system by using an electrochemical method and taking the amorphous alloy strip as a working electrode and a pure Ti or Pt electrode as a counter electrode;

and 4, taking the azo dye solution to be degraded as an electrolyte by using an electrochemical method, and adopting a potentiodynamic scanning method with a scanning potential range of-0.1-2V and a scanning speed of 1mV/s as a testing method.

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