CN114409024A - Tubular membrane electrode-based electrocatalytic oxidation process - Google Patents

Abstract

The invention relates to the field of environmental protection, in particular to sewage treatment technology, and discloses an electrocatalytic oxidation process based on a tubular membrane electrode, which mainly includes an iron-dissolving reaction pool, an inlet pump, a tubular membrane electrode, a DC power supply, a circulating pump, and a sedimentation tank. , Water tank. The process is aimed at toxic and refractory chemical wastewater, and can be coupled with the Fenton reaction to further improve the treatment efficiency of wastewater.

Description

An Electrocatalytic Oxidation Process Based on Tubular Membrane Electrode

technical field

The invention relates to the field of environmental protection, in particular to a sewage treatment technology, in particular to an electrocatalytic oxidation process based on a tubular membrane electrode.

Background technique

As a major industry in China, the chemical industry has a large amount of wastewater discharge, high discharge requirements and difficult treatment. China's chemical industry wastewater mainly comes from the production of fine chemical products such as chemicals, medicines, pesticides, dyes, electroplating and chemical materials. The discharged wastewater has the characteristics of complex composition, strong toxicity and easy accumulation in the environment. With the improvement of the state's sewage discharge standards, chemical enterprises and wastewater treatment plants in concentrated areas have implemented new standards for discharge limits, and new requirements have also been put forward for the advanced treatment and reuse of chemical wastewater.

Tubular membrane electrode equipment is a new type of complete equipment developed for difficult-to-degrade chemical wastewater. The core component of the reaction unit is the tubular porous electrode (TPE) module, which innovatively couples the electrocatalytic oxidation technology with the membrane filtration technology, which effectively improves the electrochemical oxidation efficiency and reduces the operating cost. Realize the pretreatment and deep reduction of refractory pollutants in chemical wastewater, so as to achieve the goal of standard discharge, advanced treatment and reuse of chemical wastewater.

The tubular membrane electrode equipment is mainly composed of stainless steel cathode and metal oxide coated microporous anode, which couples electrochemical oxidation and membrane separation technology. Under the action of external power, the water flow first enters the cavity between the cathode and anode, and then is forced to pass through the anode which is covered with a large number of micropores. Since the pores of the microporous anode are narrow and irregular, the probability of contaminants colliding with the pore wall when passing through the pores of the anode is greatly increased, thereby being efficiently removed.

SUMMARY OF THE INVENTION

In view of the above problems, the present invention innovatively develops a novel electrocatalytic oxidation process. This process mainly uses the tubular membrane electrode as the core to treat sewage by using the principle of electrocatalytic oxidation. It can also view the indicators of inflow and outflow water, and couple the tubular membrane electrode with the Fenton reaction to solve the problem of "Fenton stagnation". The efficiency of the Fenton reaction is greatly increased, resulting in improved treatment efficiency. The present invention is mainly applicable to the following scenarios:

(1) High organic matter and high ammonia nitrogen wastewater that is difficult to biochemically treat (petrochemical, coking, coal chemical, fine chemical, chemical park, etc.);

(2) Upgrading the existing biochemical effluent (or never reaching the standard until reaching the standard);

(3) There are organic matter and ammonia nitrogen in the RO concentrated water that need to be further processed (required before evaporation or direct efflux).

To achieve the above object, the present invention adopts the following technical solutions:

An electrocatalytic oxidation process based on a tubular membrane electrode, including an iron-dissolving reaction tank, an inlet pump, a tubular membrane electrode, a DC power supply, a circulating water tank, a sedimentation tank, a water production tank, an acid dosing unit, and a hydrogen peroxide dosing unit ;

The iron-dissolving reaction tank is a water tank made of PE material, and a certain number of iron alloy pole plates with equal spacing are placed in it to provide a certain amount of divalent iron ions for the Fenton reaction;

The tubular membrane electrode has a tubular shape and an internal structure of a Ti-RuO ₂ filter electrode and a stainless steel cathode. The multi-branched membrane electrodes are evenly arranged in the stainless steel reactor, and 3-6 branched tubular membrane electrodes are arranged in parallel in each stainless steel reactor, and each reactor is a set. Each reactor has one water inlet, one water outlet, and one circulation port. Wherein, the circulation port is the anode water outlet of the multi-branched membrane electrode connected with each other to form a total circulation port.

The DC power supply is a device that inputs alternating current and outputs direct current, and the current can be adjusted manually.

In the sedimentation tank, under alkaline conditions, the pH of the sedimentation tank can precipitate and remove iron ions in the effluent of the membrane electrode, and its flocculation effect can also remove some organic substances.

The acid dosing unit keeps the iron-dissolving reaction pool in an acidic condition with a pH value of 2-3, so that the iron ions in the iron-dissolving reaction pool can be maintained in the state of divalent iron.

The hydrogen peroxide dosing unit is to provide the raw material H ₂ O ₂ for the Fenton reaction.

Further, multiple tubular membrane electrodes are connected in series to ensure that the sewage has sufficient residence time inside the equipment.

Further, the tubular membrane electrode can also be coupled with the Fenton reaction to further improve the water effluent effect.

Further, the inlet water pump drives the sewage into the power equipment of the membrane electrode.

Further, the clarified water discharged from the sedimentation tank enters the water production tank.

Further, the acid dosing unit includes an acid solution tank, an acid dosing pump, and pipes and valves on the pipes.

Further, the hydrogen peroxide dosing port is located at the water inlet of the membrane electrode.

Further, the pH value of the alkaline conditions in the sedimentation tank is about 10.

Compared with the prior art, the beneficial effects of the present invention are:

(1) the process of the present invention is simple, and can be used for highly toxic and refractory chemical waste water;

(2) The number of electrodes can be selected according to the water quality, which is flexible and has wider adaptability.

(3) Each membrane electrode does not affect each other, only a single membrane electrode needs to be removed during maintenance, which is more convenient for maintenance and replacement.

(4) Coupling the electrocatalysis with the Fenton reaction, while improving the electrocatalytic oxidation effect, the efficiency of the Fenton catalytic oxidation can also be improved, so that the sewage treatment effect is better.

Description of drawings

Fig. 1 is the process flow diagram of the present invention;

The meaning of each label in the figure is: 1- iron-dissolving reaction tank; 2- feed pump; 3- DC power supply group; 4- circulating water tank; 5- tubular membrane electrode group; 6- that element of acid dosing; 7- Hydrogen peroxide dosing unit; 8 - alkali dosing unit; 9 - sedimentation tank; 10 - water production tank; 11 - manual valve group; 12 - tubular membrane electrode reactor.

Detailed ways:

Below in conjunction with accompanying drawing, the present invention is described in detail:

As shown in Figure 1, an electrocatalytic oxidation process based on a tubular membrane electrode includes an iron-dissolving reaction tank, an inlet pump, a tubular membrane electrode, a DC power supply, a circulating water tank, a sedimentation tank, a water production tank, an acid dosing unit, Hydrogen peroxide dosing unit;

The iron-dissolving reaction tank is a water tank made of PE material, and a certain number of iron alloy electrode plates are placed in it.

The iron alloy pole plate is mainly made of iron, the pole plate is connected to a DC power supply, and the two adjacent pole plates are respectively connected to the positive pole and the negative pole of the power supply.

The tubular membrane electrode has a tubular shape, and the internal structure is a Ti-RuO ₂ filter electrode and a stainless steel cathode. The multi-branched membrane electrodes are evenly arranged in the stainless steel reactor, and 3-6 branched tubular membrane electrodes are arranged in parallel in each stainless steel reactor, and each reactor is a set. Each reactor has one water inlet, one water outlet, and one circulation port. Wherein, the circulation port is the anode water outlet of the multi-branched membrane electrode connected with each other to form a total circulation port.

The tubular membrane electrode can also be coupled with the Fenton reaction to further improve the water effluent effect.

The DC power supply can input AC power and output DC power, and can manually adjust the current size of the device.

The said inlet water pump drives the sewage into the power equipment of the membrane electrode.

The sedimentation tank removes iron ions in the effluent from the membrane electrode by precipitation.

The water production tank collects the produced water discharged from the sedimentation tank after being treated by the membrane electrode.

The acid dosing unit provides acidic conditions of pH=3 for the iron-dissolving reaction pool, so that the iron ions in the iron-dissolving pool are maintained in the state of ferrous iron.

The hydrogen peroxide dosing unit is the raw material H ₂ O ₂ of the Fenton reaction, and the dosing port is located on the water inlet pipe of the membrane electrode.

The alkali dosing unit provides alkaline conditions for the sedimentation tank to precipitate iron ions in water.

The alkaline condition is that the pH value is about 10.

The technical principle of the present invention is:

The sewage first enters the iron-dissolving reaction tank. According to the content of organic matter in the reaction tank, the content of the added divalent iron ions is controlled by adjusting the current, and the pH value is adjusted to 2 to 3 in the reaction tank to maintain the stability of the divalent iron ions. . After that, the acidic wastewater containing ferrous ions is pumped into the membrane electrode through the inlet pump, and the hydrogen peroxide dosing port is mixed with the sewage at the inlet of the membrane electrode and enters the membrane electrode together. Electrocatalytic oxidation reaction and Fenton reaction occur inside the membrane electrode. However, the so-called "reaction stagnation" problem occurs in the Fenton reaction, that is, the complex reaction between ferrous ions and low-molecular organic acids occurs, resulting in a decrease in the utilization rate of ferrous iron. However, the complex reaction between ferrous ions and low-molecular-weight organic acids can be eliminated in the membrane electrode, so the efficiency of the Fenton reaction can be greatly improved. Therefore, the perfect coupling of electrocatalytic oxidation and Fenton oxidation can be achieved inside the membrane electrode, and the effect of "1+1>2" can be achieved. The effluent after the membrane electrode reaction enters the sedimentation tank, and the sedimentation tank controls pH=10 to precipitate the iron ions after the reaction, and the flocculation effect of the iron ions can also take away part of the organic matter. The upper layer of clean water in the sedimentation tank flows into the water production tank, and the iron sludge produced is discharged through the lower sludge discharge port.

Claims (10)

1. an electrocatalytic oxidation process based on tubular membrane electrode, it is characterized in that: comprise molten iron reaction tank, feed pump, tubular membrane electrode group, DC power supply, circulating water tank, sedimentation tank, water production tank, acid dosing unit , Hydrogen peroxide dosing unit, alkali dosing unit. 2. a kind of electrocatalytic oxidation process based on tubular membrane electrode according to claim 1, it is characterized in that: described iron-dissolving reaction tank is the pool of PE material, and a certain number of iron alloy pole plates are placed in it, which is Fenton Provides divalent iron ions. 3. A kind of electrocatalytic oxidation process based on tubular membrane electrode according to claim 1, it is characterized in that: the outer shape of the membrane electrode of described tubular membrane electrode is tubular, and the internal structure is Ti _- RuO filter electrode, Stainless steel cathode; 3-6 branched tubular membrane electrodes are placed in each stainless steel reactor and arranged in parallel, each reactor is a set; each reactor has one water inlet, one water outlet, and one circulation port; among them, the circulation port The anode water outlet of the multi-branched membrane electrode is connected to each other to form a total circulation port. 4 . The electrocatalytic oxidation process based on a tubular membrane electrode according to claim 1 , wherein the tubular membrane electrode can be coupled with the Fenton reaction to further improve the water effluent effect. 5 . 5 . The electrocatalytic oxidation process based on a tubular membrane electrode according to claim 1 , wherein the DC power supply is a device that inputs alternating current and outputs direct current, and the magnitude of the current can be adjusted manually. 6 . 6 . The electrocatalytic oxidation process based on a tubular membrane electrode according to claim 1 , wherein the sedimentation tank removes metal ions, especially iron ions, in the effluent of the membrane electrode by precipitation. 7 . 7. A kind of electrocatalytic oxidation process based on tubular membrane electrode according to claim 1, it is characterized in that: described acid dosing unit provides the acidic condition of pH=3 for the iron-dissolving reaction tank, so that the iron-dissolving tank is The iron ions are maintained in the state of ferrous iron. 8 . The electrocatalytic oxidation process based on a tubular membrane electrode according to claim 1 , wherein the hydrogen peroxide dosing unit is the raw material H ₂ O ₂ of the Fenton reaction, and its dosing port is located at on the water inlet pipe of the membrane electrode. 9 . The electrocatalytic oxidation process based on tubular membrane electrodes according to claim 1 , wherein the alkali dosing unit provides alkaline conditions for the sedimentation tank to precipitate iron ions in water. 10 . 10 . The electrocatalytic oxidation process based on a tubular membrane electrode according to claim 6 , wherein the pH value in the sedimentation tank is 10. 11 .

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