CN106044955A - A Method of Adding Surfactant to Improve Micro-plasma Arc Discharge Catalytic Water Treatment - Google Patents

Abstract

The present invention discloses a method for improving microplasma arc discharge catalytic water treatment by adding surfactant, which comprises the following steps: adding additives and surfactants to the liquid to be treated; opening the cooling water circulation system and the stirring system; inserting electrodes I and II into a reaction tank; adding the liquid to be treated containing additives and surfactants into the reaction tank; connecting the power supply between the electrodes I and II, and gradually increasing the voltage so that the power supply discharges stably under the parameters of the power supply; analyzing the water treatment effect; and the water treatment ends. The present invention uses the addition of surfactants to treat wastewater by micro-arc discharge, and the small amount of surfactant added can enhance the stability of bubbles generated during discharge and bubbles generated by stirring. Since bubbles promote discharge by affecting plasma chemical reactions and mass transfer, the treatment effect is also improved as the amount of surfactant added increases.

Description

A Method of Adding Surfactant to Improve Micro-plasma Arc Discharge Catalytic Water Treatment

technical field

The invention belongs to the technical field of environmental engineering water treatment, and relates to a method for improving micro-plasma arc discharge catalytic water treatment by adding a surfactant.

Background technique

Under the action of an electric field, the plasma generated during the liquid phase discharge process contains a large number of high-energy active particles, which can damage many molecules. The combination of these high-energy active particles and catalysts can effectively improve the discharge treatment effect and promote the decomposition of organic molecules, so it has become a hot spot in the research and development of pollution treatment technology.

In the micro-arc discharge with titanium-containing valve metal as the working electrode, the titanium dioxide that can be generated in situ on the electrode can play a catalytic role in the plasma generated by the discharge, and strengthen the formation of hydroxyl radicals. That is, the discharge system forms a naturally integrated liquid-phase plasma-catalysis synergistic system. At the same time, the O ₂ gas generated by electrolysis on the working electrode provides a gas phase space that is easy to discharge, and O ₂ provides reactants for OH radicals. Therefore, compared with adding a catalyst to the electrolyte and passing an oxygen-containing gas to enhance the discharge, this system can more fully play the role of high-energy particles and high-energy environment during the discharge process, showing the diversity and synergy of the reaction and the catalyst's effect on OH. Good selectivity for free radical generating reactions.

In order to enhance the discharge intensity and improve the water treatment effect, in general liquid phase discharge, gas containing oxygen is considered to pass through, and the gas phase is used to enhance the discharge, and the oxygen in it promotes the formation of hydroxyl radicals. But this increases the complexity of the equipment and the cost of water treatment.

Contents of the invention

According to the technical problems raised above, a method for improving micro-plasma arc discharge catalytic water treatment by adding a surfactant is provided.

The technical means adopted in the present invention are as follows:

A method for improving micro-plasma arc discharge catalytic water treatment by adding a surfactant, comprising the following steps:

S1, adding additives and surfactants to the liquid to be treated;

S2, open the cooling water circulation system and the stirring system;

S3, inserting electrode I and electrode II into the reaction cell;

S4, adding the liquid to be treated containing additives and surfactants into the reaction tank;

S5. Turn on the power supply between the electrode I and the electrode II, and gradually increase the voltage, so that the power supply can discharge stably under the parameters of the power supply;

S6, analyze water treatment effect;

S7, the water treatment is finished,

The above methods can be divided into static treatment methods and dynamic treatment methods according to the state of the liquid to be treated.

The static processing method has the following steps:

1) Add additives and surfactants in the liquid to be treated;

2) Turn on the cooling water circulation system and stirring system;

3) Insert electrode I and electrode II into the reaction cell;

4) adding the liquid to be treated containing additives and surfactants into the reaction pool;

5) Turn on the power supply between the electrode I and the electrode II, and gradually increase the voltage, so that the power supply can discharge stably under the parameters of the power supply;

6) Analyze the water treatment effect: take samples regularly to test the water quality change of the liquid to be treated, calculate the treatment time in advance, and combine the test results to determine the end time of the treatment;

7) End of water treatment: gradually reduce the power supply voltage to 10-20V, then turn off the power supply, stirring system and cooling water circulation system in sequence,

The dynamic processing method has the following steps:

1) Add additives and surfactants to the liquid to be treated, that is, add additives and surfactants to the input pipeline of the liquid to be treated;

2) Turn on the cooling water circulation system and stirring system;

3) Insert electrode I and electrode II into the reaction cell;

4) adding the liquid to be treated containing additives and surfactants into the reaction pool;

5) Turn on the power supply between the electrode I and the electrode II, and gradually increase the voltage, so that the power supply can discharge stably under the parameters of the power supply;

6) Analysis of water treatment effect: analyze the treated water quality flowing out of the reaction tank, and adjust the flow of liquid in and out of the reaction tank according to the test results, so that the treatment effect meets the requirements;

7) End of water treatment: Stop inputting the liquid to be treated into the reaction pool, gradually reduce the voltage to 10-20V, and then turn off the power supply, the stirring system and the cooling water circulation system in sequence.

When the power supply is a unipolar power supply, the electrode I is a working electrode;

When the power supply is a bipolar power supply, the electrode I and electrode II electrodes are both working electrodes,

The material of the working electrode is titanium-containing valve metal and its alloys,

The concentration of the additive is 0.5-50g/L, and the additive is one or more of sodium silicate, sodium carbonate, sodium aluminate or sodium sulfate.

A voltage is applied to the reaction system through the electrode I and the electrode II, so that the surface of the working electrode can generate a supported catalyst in situ for discharge catalysis.

The concentration of the surfactant is 0.1-500ppm, and the surfactant is one or more of alkyl glycoside, ammonium oxide, alkenyl glycol ester, glyceride or alkanolamide series. The surfactant content is lower than the COD limit in the relevant wastewater discharge standards.

Before the reaction, the liquid to be treated starts to be fully stirred, which is not only to enhance the material transfer, but also to generate air bubbles. In addition, the working electrode will also generate oxygen-containing bubbles during the reaction. Surfactants have high surface activity, can effectively reduce the surface tension of the liquid, and arrange the double electron layer on the surface of the liquid film to surround the air, forming bubbles, and then forming a foam from a single bubble. Therefore, the surfactant can make the bubbles in the liquid to be treated to exist in the liquid more stably. Due to the addition of a small amount of surfactant, the treatment effect can be improved only by strengthening the stirring effect.

The unipolar power supply is a DC power supply with a voltage of 80V-1kV or a unipolar pulse power supply with a peak voltage of 80V-1kV.

The bipolar power supply is an AC power supply or a bipolar pulse power supply with a peak voltage of 80V-1kV and a switching frequency of 10 ^-3 -10 ⁵ Hz.

The valve metal is titanium, magnesium or aluminum.

The shape of the working electrode is plate or needle.

The electrode surface area of the working electrode in the liquid to be treated is 5 mm ² -1 dm ² .

The electrode distance between the electrode I and the electrode II is 2-50 mm.

The above parameters should be determined according to the structure of the treatment system, the water quality of the liquid to be treated, the analysis of the kinetic reaction rate constant, the stability of the discharge and the actual treatment effect to determine its optimal value.

The present invention has the following advantages:

The invention adopts adding surfactant to carry out micro-arc discharge to treat waste water. Surfactant is a substance with fixed hydrophilic and lipophilic groups, which can significantly change the interface state of the solution system when added in a small amount. It has good foaming and foam stabilizing properties. A small amount of surfactant added can Enhance the stability of the bubbles generated in the discharge and the bubbles generated by stirring. Since the bubbles promote the discharge by affecting the plasma chemical reaction and mass transfer, the treatment effect is also improved with the increase of the amount of surfactant added.

Based on the above reasons, the present invention can be widely promoted in the fields of environmental engineering water treatment technology and the like.

Description of drawings

The present invention will be further described in detail below in conjunction with the accompanying drawings and specific embodiments.

Fig. 1 is a schematic structural diagram of a processing device in a specific embodiment of the present invention.

detailed description

A method for improving micro-plasma arc discharge catalytic water treatment by adding a surfactant, comprising the following steps:

S1, adding additives and surfactants to the liquid to be treated;

S2, open the cooling water circulation system and the stirring system;

S3, inserting electrode I and electrode II into the reaction cell;

S4, adding the liquid to be treated containing additives and surfactants into the reaction tank;

S5. Turn on the power supply between the electrode I and the electrode II, and gradually increase the voltage, so that the power supply can discharge stably under the parameters of the power supply;

S6, analyze water treatment effect;

S7, the water treatment is finished,

When the power supply is a unipolar power supply, the electrode I is a working electrode;

When the power supply is a bipolar power supply, the electrode I and electrode II electrodes are both working electrodes,

The material of the working electrode is titanium-containing valve metal and its alloys,

The concentration of the additive is 0.5-50g/L, and the additive is one or more of sodium silicate, sodium carbonate, sodium aluminate or sodium sulfate.

The concentration of the surfactant is 0.1-500ppm, and the surfactant is one or more of alkyl glycoside, ammonium oxide, alkenyl glycol ester, glyceride or alkanolamide series.

The unipolar power supply is a DC power supply with a voltage of 80V-1kV or a unipolar pulse power supply with a peak voltage of 80V-1kV.

The bipolar power supply is an AC power supply or a bipolar pulse power supply with a peak voltage of 80V-1kV and a switching frequency of 10 ^-3 -10 ⁵ Hz.

The valve metal is titanium, magnesium or aluminum.

The shape of the working electrode is plate or needle.

The electrode surface area of the working electrode in the liquid to be treated is 5 mm ² -1 dm ² .

The electrode distance between the electrode I and the electrode II is 2-50mm.

Example 1

A method for improving micro-plasma arc discharge catalytic water treatment by adding a surfactant, comprising the following steps:

1) Add additives and surfactants in the liquid to be treated 1;

2) Turn on the cooling water circulation system 2 and the magnetic stirring system 3;

3) Insert the electrode I4 and the electrode II5 into the reaction cell 6;

4) adding the liquid to be treated 1 containing additives and surfactants into the reaction tank 6;

5) Connecting the DC power supply 7 between the electrode I4 and the electrode II5, and gradually increasing the voltage, so that the DC power supply 7 can discharge stably under the parameters of the DC power supply 7;

6) Analyzing the water treatment effect: taking regular samples to test the water quality change of the liquid 1 to be treated, calculating the treatment time in advance, and combining the test results to determine the end time of the treatment;

7) End of water treatment: gradually reduce the voltage of the DC power supply 7 to 10-20V, then turn off the DC power supply 7, the magnetic stirring system 3 and the cooling water circulation system 2 in sequence,

The concentration of the additive is 15g/L, and the additive is sodium silicate, and the surfactant is coconut oil monoethanolamide, and the concentration is 10ppm. The cocoic acid monoethanolamide belongs to the series of alkanolamides.

The electrode I4 is a working electrode, and its material includes the following parts by weight: titanium: 70 parts, aluminum: 30 parts, and unavoidable trace elements. The material of electrode II5 is stainless steel,

The DC power supply 7 is a DC power supply with a voltage of 500V.

The electrode spacing between the electrode I4 and the electrode II5 is 10 mm.

The electrode surface areas of the electrode I4 and the electrode II5 located in the liquid to be treated 1 are both 6000 mm ² .

Both the electrode I4 and the electrode II5 are plate electrodes.

In this embodiment, the distilled water added with Brilliant Red B is used to simulate the liquid 1 to be treated. The Brilliant Red B belongs to the weak acid dye of azo dyes, is a dye commonly used in the printing and dyeing industry and the textile industry, and contains a benzene ring. The effect of treating this kind of wastewater by biological and biological methods is not ideal. The initial concentration of Brilliant Red B solution is 20 mg/L, and the content of the liquid to be treated 1 is 1000 mL.

During the process of treating the liquid 1 to be treated, the change of absorbance at the maximum absorption wavelength of the liquid 1 to be treated is measured by an ultraviolet-visible spectrophotometer to reflect the decolorization effect of the Brilliant Red B solution.

The experimental results show that, compared with no surfactant, the decolorization rate of the liquid 1 to be treated with the addition of the surfactant can be increased by 10% within 6 minutes.

Example 2

A method of adding a surfactant to improve micro-plasma arc discharge catalytic water treatment, which differs from the method of adding surfactant to improve micro-plasma arc discharge catalytic water treatment described in Example 1 as follows:

The surfactant is alkenyl glycol ester with a concentration of 5 ppm.

The experimental results show that adding the same amount of surfactant, the treatment effect can also be improved by only appropriately increasing the stirring intensity before the reaction. The effect of stirring 150s before the reaction is higher than that of stirring 30s before the reaction, about 10% higher.

Example 3

A method of adding a surfactant to improve micro-plasma arc discharge catalytic water treatment, which differs from the method of adding surfactant to improve micro-plasma arc discharge catalytic water treatment described in Example 1 as follows:

The surfactant is an alkyl glycoside with a concentration of 10 ppm.

The experimental results show that adding surfactant and stirring in a proper way can increase the decolorization rate by 8% in 4 minutes compared with no surfactant because bubbles are introduced and the bubbles can stay in the liquid phase relatively stably.

The above is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto, any person familiar with the technical field within the technical scope disclosed in the present invention, according to the technical solution of the present invention Any equivalent replacement or change of the inventive concepts thereof shall fall within the protection scope of the present invention.

Claims (8)

1. a kind of adding tensio-active agent improves micro-plasma arc discharge catalytic water treatment method, it is characterized in that having the following steps: S1, adding additives and surfactants to the liquid to be treated; S2, open the cooling water circulation system and the stirring system; S3, inserting electrode I and electrode II into the reaction cell; S4, adding the liquid to be treated containing additives and surfactants into the reaction tank; S5. Turn on the power supply between the electrode I and the electrode II, and gradually increase the voltage, so that the power supply can discharge stably under the parameters of the power supply; S6, analyze water treatment effect; S7, the water treatment is finished, When the power supply is a unipolar power supply, the electrode I is a working electrode; When the power supply is a bipolar power supply, the electrode I and electrode II electrodes are both working electrodes, The material of the working electrode is titanium-containing valve metal and its alloys, The concentration of the additive is 0.5-50g/L, and the additive is one or more of sodium silicate, sodium carbonate, sodium aluminate or sodium sulfate. 2. The method according to claim 1, characterized in that: the concentration of the surfactant is 0.1-500ppm, and the surfactant is an alkyl glucoside, ammonium oxide, vinyl glycol ester, glyceride or One or more of the alkanolamide series. 3. The method according to claim 1, wherein the unipolar power supply is a DC power supply with a voltage of 80V-1kV or a unipolar pulse power supply with a peak voltage of 80V-1kV. 4. The method according to claim 1, wherein the bipolar power supply is an AC power supply or a bipolar pulse power supply with a peak voltage of 80V-1kV and a switching frequency of 10 ^-3 -10 ⁵ Hz. 5. The method of claim 1, wherein the valve metal is titanium, magnesium or aluminum. 6. The method according to claim 1, characterized in that: the shape of the working electrode is plate or needle. 7. The method according to claim 1, characterized in that: the electrode surface area of the working electrode located in the liquid to be treated is 5 mm ² -1 dm ² . 8. The method according to claim 1, characterized in that: the electrode spacing between the electrode I and the electrode II is 2-50 mm.