CN102126778A - Groove-type device and method for treating organic wastewater by multiphase electro-catalytic oxidation - Google Patents

Abstract

The invention discloses a multiphase electrocatalytic oxidation treatment organic wastewater tank type device and a method thereof. It includes an electrocatalytic oxidation tank, an electrode plate support, a cylindrical anode, a plate cathode, an intermediate medium, a catalyst, a water inlet, an air inlet, a water outlet, a tank body support, an inner medium support and an overflow tank. The acidic organic wastewater enters the heterogeneous electrocatalytic oxidation tank, and an oxidant is added at the same time, and the electrocatalytic oxidation reaction is carried out in the electrocatalytic oxidation tank. The electrode is graphite-loaded titanium dioxide; the catalyst is acid-resistant magnet powder and goethite powder. The intermediate medium is attapulgite and tourmaline; the oxidant is hydrogen peroxide, air, chlorine dioxide and potassium permanganate. Add liquid caustic soda or lime water to the reacted wastewater to adjust the pH value to 7, then enter the sedimentation tank for precipitation, and the precipitated wastewater enters the biochemical treatment system for treatment. The invention has the advantages of high processing efficiency, less land occupation, and low operating cost.

Description

A multiphase electrocatalytic oxidation treatment organic wastewater tank type device and method thereof

technical field

The invention relates to a high-concentration organic wastewater treatment device and a method thereof, in particular to a method for treating high-concentration organic wastewater mainly by adopting multiphase electrocatalytic oxidation technology. It belongs to the technical field of sewage treatment.

Background technique

With the rapid development of my country's chemical industry, medicine, dyestuff and other industries, my country's economic strength has been gradually improved; at the same time, in parallel with this, the waste water discharged in the production process is also increasingly polluting the environment and causing serious damage to human health. threaten. Due to the complex composition, high organic content, high salt content, high chroma and toxicity of wastewater from chemical, pharmaceutical, and dye industries, it is difficult to treat such wastewater both technically and economically. Incineration method or simple surface treatment followed by large multiple dilution followed by biochemical treatment, these methods often require high investment, occupy a large area, and have high operating costs, which are unaffordable for users.

High-concentration organic wastewater oxidation treatment technology is a research hotspot and technical difficulty in the field of environmental protection today. The heterogeneous electrocatalytic oxidation method is to use the latest developed high-efficiency catalyst to destructively oxidize the wastewater with complex components, high organic content, high salt content, chromaticity and toxicity under milder conditions through the action of oxidants after electrification , which is an oxidation technology that combines the latest technology in the chemical industry with corresponding high-efficiency catalysts, and represents the main trend of this type of sewage treatment abroad. This technology has the advantages of high processing efficiency, wide applicability, low processing cost, convenient operation and management, etc., and has broad application prospects.

Contents of the invention

The object of the present invention is to overcome the deficiencies of the prior art, and provide a multiphase electrocatalytic oxidation treatment organic wastewater tank-type device and method thereof.

The multiphase electrocatalytic oxidation treatment organic wastewater tank device includes: a multiphase electrocatalytic oxidation treatment organic wastewater tank device, which is characterized in that it includes an electrocatalytic oxidation tank, an electrode plate support, a cylindrical anode, a plate cathode, and an intermediate medium , catalyst, water inlet, air inlet, water outlet, tank support, inner medium support and overflow tank; the lower end of the electrocatalytic oxidation tank is provided with tank support, and the upper end of the electrocatalytic oxidation tank is provided with overflow tank and electrode plate support , a cylindrical anode and a plate-shaped cathode are arranged under the electrode plate support, an inner medium support is arranged at the lower part of the electrocatalytic oxidation tank, an intermediate medium and a catalyst are arranged on the inner medium support, and an air inlet is arranged under the inner medium support, and the electrocatalytic oxidation A water inlet is provided at the bottom of the tank, and a water outlet is provided on the overflow tank.

The intermediate medium in the multiphase electrocatalytic oxidation treatment organic wastewater tank-type device and the intermediate medium in the catalyst are: attapulgite and tourmaline.

The intermediate medium and the catalyst in the multi-phase electrocatalytic oxidation treatment organic wastewater tank-type device are: acid-resistant magnet powder ferric oxide and goethite powder.

The multi-phase electrocatalytic oxidation treatment organic wastewater tank-type device is made of steel, lined with fiberglass fiber and epoxy resin for anticorrosion.

The heterogeneous electrocatalytic oxidation treatment method of the device is as follows: the organic wastewater is first adjusted to pH with sulfuric acid or sodium hydroxide to make it acidic, and then the organic wastewater enters the multiphase electrocatalytic oxidation tank from the bottom of the multiphase electrocatalytic oxidation tank , at the same time, oxidants are added to the wastewater, wherein the oxidants are hydrogen peroxide, air, chlorine dioxide and potassium permanganate, and the electrocatalytic oxidation reaction is carried out in the electrocatalytic oxidation tank. The catalytic oxidation reaction time is 2 to 8h, and the DC voltage between the electrodes 5~15V, current density 2~20mA/cm ² , add liquid caustic soda or lime water to adjust the pH value to 7, and then enter the sedimentation tank for sedimentation, and the sedimented wastewater enters the biochemical treatment system for treatment.

The way in which the organic wastewater enters the multiphase electrocatalytic oxidation tank from the bottom of the multiphase electrocatalytic oxidation tank is continuous or intermittent water inflow and outflow.

The present invention has the beneficial effect compared with prior art:

(1) Realized heterogeneous electrocatalytic oxidation under acidic conditions.

(2) An acid-resistant catalyst is used.

(3) The electrode material is selected as a semiconductor medium, which improves the processing efficiency.

(4) The processing flow is simple, the operation is easy, and automatic control can be realized.

Description of drawings

Fig. 1 is a structural diagram of the electrocatalytic oxidation device of the present invention.

In the figure, electrocatalytic oxidation tank 1, electrode plate support 2, cylindrical anode 3, plate cathode 4, intermediate medium, catalyst 5, water inlet 6, air inlet 7, water outlet 8, tank support 9, inner medium Support 10 and overflow tank 11.

Detailed ways

The multiphase electrocatalytic oxidation treatment organic wastewater tank device includes: electrocatalytic oxidation tank 1, electrode plate support 2, cylindrical anode 3, plate cathode 4, intermediate medium, catalyst 5, water inlet 6, air inlet 7, outlet Nozzle 8, tank support 9, inner medium support 10, and overflow tank 11; the lower end of the electrocatalytic oxidation tank 1 is provided with a tank support 9, and the upper end of the electrocatalytic oxidation tank 1 is provided with an overflow tank 11 and an electrode plate support 2, and the electrode A columnar anode 3 and a plate-shaped cathode 4 are arranged under the plate support 2, an inner medium support 10 is arranged at the bottom of the electrocatalytic oxidation tank 1, an intermediate medium and a catalyst 5 are arranged on the inner medium support 10, and an inlet medium is arranged under the inner medium support 10. Gas port 7, water inlet 6 is provided at the bottom of electrocatalytic oxidation tank 1, and water outlet 8 is provided on overflow tank 11.

The intermediate medium in the multiphase electrocatalytic oxidation treatment organic wastewater tank-type device and the intermediate medium in the catalyst 5 are: attapulgite and tourmaline.

The intermediate medium and the catalyst in the catalyst 5 of the heterogeneous electrocatalytic oxidation treatment organic wastewater tank-type device are: acid-resistant magnet powder ferric oxide and goethite powder.

The multi-phase electrocatalytic oxidation treatment organic wastewater tank-type device is made of steel, lined with fiberglass fiber and epoxy resin for anticorrosion.

The heterogeneous electrocatalytic oxidation treatment method of the device is as follows: the organic wastewater is first adjusted to pH with sulfuric acid or sodium hydroxide to make it acidic, and then the organic wastewater enters the multiphase electrocatalytic oxidation tank from the bottom of the multiphase electrocatalytic oxidation tank , at the same time, oxidants are added to the wastewater, wherein the oxidants are hydrogen peroxide, air, chlorine dioxide and potassium permanganate, and the electrocatalytic oxidation reaction is carried out in the electrocatalytic oxidation tank. The catalytic oxidation reaction time is 2 to 8h, and the DC voltage between the electrodes 5~15V, current density 2~20mA/cm ² , add liquid caustic soda or lime water to adjust the pH value to 7, and then enter the sedimentation tank for sedimentation, and the sedimented wastewater enters the biochemical treatment system for treatment.

The way in which the organic wastewater enters the multiphase electrocatalytic oxidation tank from the bottom of the multiphase electrocatalytic oxidation tank is continuous or intermittent water inflow and outflow.

The specific operation method of the heterogeneous electrocatalytic oxidation treatment of organic wastewater by the device: first adjust the pH value of the organic wastewater with sulfuric acid or sodium hydroxide, and generally control it at 1-3. The wastewater with adjusted pH value is pumped into the multiphase electrocatalytic oxidation tank through a corrosion-resistant sewage pump for catalytic oxidation. The oxidation time is 2-8h, the DC voltage between the electrodes is 5-15V, and the current density is 2-20mA/cm ^2. It can be adjusted according to different influent water quality and treatment degree. The electrode is graphite-loaded titanium dioxide; the catalyst is acid-resistant magnet powder triiron tetroxide and goethite powder. The intermediate medium is attapulgite and tourmaline; the dosage ratio is: 1:1~5:1, and the dosage is 20~60% of the total volume; the oxidant is hydrogen peroxide, air, chlorine dioxide and potassium permanganate. Under the action of an external electric field, multiphase electrocatalytic oxidation is carried out: using intermediate media with catalytic and adsorption functions such as attapulgite and tourmaline to enrich organic pollutants on the surface of the media; due to the adsorption capacity of various adsorption media and The adsorption range is different, and various pollutants can be adsorbed. Pollutants are continuously enriched from the water phase to the surface of the solid phase. Under normal temperature and pressure conditions, they can be continuously and rapidly decomposed under the multiple synergistic effects of oxidants, catalysts, and electric fields, changing the characteristic pollutants in wastewater such as benzene rings, Structures such as heterocycles can convert macromolecular organic matter into small molecules or carbon dioxide and water, so as to achieve the purpose of continuous and efficient treatment of organic matter, and can also improve the biodegradability of wastewater. The pH value of the wastewater after the heterogeneous electrocatalytic oxidation reaction can be increased to 4-6, and the pH value is adjusted to 7-8 by adding liquid caustic soda or lime water, and then enters the sedimentation tank for precipitation, and the precipitated wastewater enters the biochemical treatment system for treatment.

Electrocatalytic oxidation mechanism : In the electrocatalytic system, there are strong oxidizing active substances, including H ₂ O ₂ , O ₃ , HO ^- , HO ₂ ^- , O ₂ ^- . And solvated electrons e _s , etc., if there is Cl ^- in the solution, there may also be Cl ₂ , HClO ^- and ClO ^_ and other oxidants. The presence of these strong oxidizing substances can greatly improve the ability to degrade organic matter. Table 1 lists the standard reduction electrode potentials of some strong oxidizing substances.

Table 1 Standard reduction electrode potential table of strong oxidizing substances

Types of strong oxidizing agents Standard potential/V Types of strong oxidizing agents Standard potential/V HO ^. 2.80 _{H2O2 _} 1.78 O ₂ ^- 2.42 HO ₂ ^- 1.70 O ₃ 2.07 ^Cl- 1.36

As can be seen from the above table, they all have quite high reduction potentials and are capable of oxidizing most organic compounds.

In the electrocatalytic system, O ₂ generated by electrolysis or O ₂ provided by the outside can be reduced on the cathode to generate H ₂ O ₂ .

酸性条件下：O₂＋2H⁺+2e^-    H₂O₂

Under acidic conditions: O ₂ +2H ⁺ +2e ^- H ₂ O ₂

碱性条件下：O₂＋H₂O+2e^-    HO₂ ^-＋OH^-

Under alkaline conditions: O ₂ ＋H ₂ O+2e ^- HO ₂ ^- ＋OH ^-

HO₂ ^-＋H₂O+2e^-    H₂O₂＋OH^-

HO ₂ ^- +H ₂ O+2e ^- H ₂ O ₂ +OH ^-

And the HO in the system ^. , which can be produced under the action of metal catalysts:

酸性条件下：M_red＋H⁺+ H₂O₂   M_ox＋HO^.+H₂O

Under acidic conditions: M _red ＋H ⁺ + H ₂ O ₂ M _ox ＋HO ^. +H ₂ O

碱性条件下：M_red＋H₂O₂    Mox＋HO^.＋OH^-

Under alkaline conditions: M _red ＋H ₂ O ₂ Mox＋HO ^. ＋OH ^-

Under the action of HO ^- , organic matter undergoes rapid oxidation reaction and free radical chain reaction, thereby being rapidly degraded.

Graphite supported Ti0 ₂ is a semiconductor material. The energy band structure of semiconductor particles is generally composed of a valence band filled with electrons and an empty high-energy conduction band. There is a forbidden band between the valence band and the conduction band. The electrons (e ¹ ) on the valence band of the semiconductor are excited to jump to the conduction band to form high-energy electrons (e ¹ ), which generate holes (h ⁺ ) in the valence band, and migrate to the surface of the particle under the action of the electric field. High-energy electrons ( ^e- ) are easily captured by oxidizing substances such as dissolved oxygen in water, while holes have a strong oxidation ability due to their strong ability to obtain electrons, and can absorb organic matter or OH ^- and H on their surface ₂ 0 molecules are oxidized into ·OH radicals, and ·OH free radicals oxidize organic matter in water almost non-selectively.

In terms of tasks, chemical catalytic oxidation, electrocatalytic oxidation, chemical oxidation, electrocoagulation and other coupling technologies are used to treat high-concentration organic wastewater in order to reduce the toxicity of wastewater, improve the biodegradability of wastewater, and improve the standards of wastewater, standard discharge and reclaimed water recycling. Use to create conditions.

Embodiment 1: organosilicon wastewater treatment

The organic silicon wastewater is first adjusted with sulfuric acid to make it acidic, and then the organic silicon wastewater enters the multiphase electrocatalytic oxidation tank from the bottom of the multiphase electrocatalytic oxidation tank. At the same time, an oxidant is added to the wastewater, and the oxidant is hydrogen peroxide. The electrocatalytic oxidation reaction is carried out in the tank, the catalytic oxidation reaction time is 8h, the DC voltage between the electrodes is 15V, and the current density is 20mA/cm ² , the reacted wastewater is added with liquid alkali to adjust the pH value to 7, and then enters the sedimentation tank for precipitation. The sedimented wastewater enters the biochemical treatment system for treatment.

The effluent from the production of organic silicon monomers has a high concentration of organic matter, high salt content, and poor biodegradability. See Table 1-1 for specific water quality parameters.

Table 1-1 Water quality table of organic silicon wastewater Unit: mg/l

Organosilicon wastewater was treated by electrocatalytic oxidation. The test was continued for 8 hours, and samples were taken every 2 hours to measure COD _cr and Cl ^- respectively. The test results are shown in Table 1-2 (COD _cr of raw water is 2850mg/l).

Table 1-2 Electrocatalytic oxidation test results

batch 2 hours 4 hours 6 hours 8 hours COD _cr (mg/L) 2.48×10 ³ 1.12×10 ³ 1.25×10 ³ 1.27×10 ³ Removal rate (%) 13.0 70.9 56.1 55.4 Cl ^- (mg/L) 2.12×10 ⁴ 1.82×10 ⁴ 1.73×10 ⁴ 1.83×10 ⁴

Embodiment 2: organic phosphorus wastewater treatment

The pH of glyphosate production wastewater is first adjusted with sulfuric acid to make it acidic, and then the glyphosate production wastewater enters the multiphase electrocatalytic oxidation tank from the bottom of the multiphase electrocatalytic oxidation tank. At the same time, an oxidant is added to the wastewater, and the oxidant is hydrogen peroxide. The electrocatalytic oxidation reaction is carried out in the electrocatalytic oxidation tank. The catalytic oxidation reaction time is 2h, the DC voltage between the electrodes is 5V, and the current density is 2mA/cm ² . After the reaction, add lime water to adjust the pH value to 7, and then enter The sedimentation tank settles, and the sedimented wastewater enters the biochemical treatment system for treatment.

Glyphosate production wastewater has a high concentration of organic matter, high salt content, and high organic phosphorus content, making it difficult to treat. The production process wastewater pH: 1 ~ 2, COD _cr : 20000 ~ 30000mg/l; total phosphorus (mainly organic phosphorus) > 1000mg/l.

Glyphosate production wastewater was treated by electrocatalytic oxidation method, and the test was continued for 2 hours, and COD _cr and TP were measured respectively. It is measured that the supernatant _CODcr removal rate after precipitation is greater than 40%, and the total phosphorus removal rate is greater than 75%.

Claims (6)

1. the organic waste water slot-type device is handled in a polyphase electrocatalytic oxidation, it is characterized in that comprising that catalytic oxidation groove (1), battery lead plate support (2), cylindricality anode (3), plate shape negative electrode (4), intermediate medium, catalyzer (5), water-in (6), inlet mouth (7), water outlet (8), cell body support (9), interior dielectric support (10) and overflow groove (11); Catalytic oxidation groove (1) lower end is provided with cell body and supports (9), catalytic oxidation groove (1) upper end is provided with overflow groove (11) and battery lead plate support (2), battery lead plate support (2) below is provided with cylindricality anode (3) and plate shape negative electrode (4), catalytic oxidation groove (1) bottom is provided with interior dielectric support (10), interior dielectric support (10) is provided with intermediate medium, catalyzer (5), interior dielectric support (10) below is provided with inlet mouth (7), catalytic oxidation groove (1) bottom is provided with water-in (6), and overflow groove (11) is provided with water outlet (8).

2. the organic waste water slot-type device is handled in a kind of polyphase electrocatalytic oxidation according to claim 1, it is characterized in that the intermediate medium in described intermediate medium, the catalyzer (5) is: attapulgite and tourmalinite.

3. the organic waste water slot-type device is handled in a kind of polyphase electrocatalytic oxidation according to claim 1, it is characterized in that the catalyzer in described intermediate medium, the catalyzer (5) is: acid proof magnetic iron powder Z 250 and pyrrhosiderite powder.

4. the organic waste water slot-type device is handled in a kind of polyphase electrocatalytic oxidation according to claim 1, it is characterized in that described catalytic oxidation groove (1) adopts steel, and glass inner-lining steel fiber and Resins, epoxy are anticorrosion.

5. the organic waste water method is handled in the use polyphase electrocatalytic oxidation of installing according to claim 1, it is characterized in that organic waste water makes it be acid with sulfuric acid or the adjusting pH of sodium hydroxide elder generation, organic waste water is entered in the polyphase electrocatalytic oxidation groove by polyphase electrocatalytic oxidation trench bottom then, simultaneously, add oxygenant in the waste water, wherein oxygenant is a hydrogen peroxide, air, dioxide peroxide and potassium permanganate, in the catalytic oxidation groove, carry out electrocatalysis oxidation reaction, the catalytic oxidation time is 2～8h, interelectrode volts DS is 5～15V, and current density is 2～20mA/cm ², reacted wastewater adds liquid caustic soda or liming is regulated pH value to 7, enters the settling tank precipitation again, and the waste water of post precipitation enters biochemical treatment system and handles.

6. the organic waste water method is handled in a kind of polyphase electrocatalytic oxidation according to claim 5, it is characterized in that described organic waste water by the water intake mode that polyphase electrocatalytic oxidation trench bottom enters polyphase electrocatalytic oxidation groove is: Inlet and outlet water continuously or intermittently.

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