CN116874043A - Electrochemical double-membrane reactor and wastewater treatment method based on electrochemical double-membrane reactor - Google Patents

Abstract

The invention provides an electrochemical double-membrane reactor and a wastewater treatment method based on the electrochemical double-membrane reactor, and belongs to the technical field of membrane separation and electrochemical advanced oxidation. The invention provides a wastewater treatment method based on an electrochemical double-membrane reactor, which is used for coupling membrane separation and electrochemical advanced oxidation technology by the first stepOne conductive microporous membrane is used as an anode membrane, a second conductive microporous membrane is used as a cathode membrane, the anode membrane generates hydroxyl radicals by water electrolysis, and the cathode membrane generates H by electroreduction of oxygen ₂ O ₂ And further converted into hydroxyl free radicals by a Fenton catalyst, and the hydroxyl free radicals and the Fenton catalyst are cooperatively catalyzed to generate singlet oxygen so as to remove refractory organic matters and/or heavy metals in the wastewater. The electrochemical double-membrane reactor provided by the invention can enable a plurality of active substances to act together in the electrochemical process, so that the removal of refractory organic matters and heavy metals in wastewater is realized, and the electrochemical double-membrane reactor can be widely applied to the treatment and recycling of industrial wastewater, landfill leachate and the like.

Description

Electrochemical double membrane reactor and wastewater treatment method based on electrochemical double membrane reactor

Technical field

The invention belongs to the technical fields of membrane separation and electrochemical advanced oxidation, and in particular relates to an electrochemical double membrane reactor and a wastewater treatment method based on the electrochemical double membrane reactor.

Background technique

In recent years, electrochemical membrane technology based on the electrochemical advanced oxidation process has been considered one of the most promising candidates for next-generation water purification technology. Its ability to break down wastewater pollutants in situ has the potential to surpass traditional membrane filtration technologies that rely on physical trapping and transfer of pollutants. And electrochemical advanced oxidation gives the electrochemical membrane multiple functions, such as electrocatalysis and electro-Fenton degradation, electrodisinfection, antifouling, etc., which has huge application potential in the fields of environment, energy, medical and other fields. Although the membrane filtration process improves electrochemical efficiency by enhancing mass transfer and confinement effects, efficiency and energy consumption are still key issues limiting the development of electrochemical membrane technology.

Electrochemical membrane reactors mainly consist of an anode and a cathode. Currently, most relevant research focuses on half-cell reactions with a single electrocatalytic membrane as the anode or a single electro-Fenton membrane as the cathode (with a relatively inert counter electrode). CN101597096A discloses an electrocatalytic membrane reactor device, which uses an electrocatalytic composite membrane as an anode and a stainless steel mesh as a cathode to construct an electrocatalytic membrane reactor device that couples membrane separation technology and electrocatalytic technology for wastewater treatment. The use of hydroxyl radicals generated by electrocatalysis to oxidize and decompose pollutants can effectively solve the problem of membrane fouling and realize the self-cleaning function of the membrane. The reactor can be used for the treatment and reuse of industrial wastewater such as oily wastewater, dye wastewater, and papermaking wastewater. CN103193297A discloses a sewage treatment method that couples organic membrane and electro-Fenton catalysis technology. It uses a conductive polymer-modified organic fabric membrane as the cathode and a stainless steel mesh as the anode to construct a method that combines organic membrane separation and electro-Fenton catalysis technology. The electro-Fenton membrane system uses the cathode to electrically reduce oxygen to produce hydrogen peroxide, which further generates hydroxyl radicals under the action of the Fenton catalyst, which can effectively reduce the pollution and load of the membrane module. The membrane filtration enhances the effective contact between pollutants and membrane electrodes. reaction and is conducive to the removal of large particle pollutants that are not easily degraded.

However, in the existing anodic membrane reactor and cathodic membrane reactor wastewater treatment process, since only a single anode or a single cathode works, the power of the auxiliary counter electrode (such as stainless steel mesh) is wasted, which greatly limits the electrochemical membrane technology. development of. In order to solve this problem, it is imperative to couple the cathode and anode together to degrade pollutants, which can not only improve the degradation efficiency of the reactor, but also reduce energy consumption.

Contents of the invention

The invention provides an electrochemical double-membrane reactor and a wastewater treatment method based on the electrochemical double-membrane reactor. The electrochemical double-membrane reactor can make a variety of active substances work together during the electrochemical process to realize the treatment of wastewater. The removal of refractory organic matter and heavy metals can be widely used in the treatment and reuse of industrial wastewater, landfill leachate, etc.

In order to achieve the above objectives, the present invention provides a wastewater treatment method based on an electrochemical double membrane reactor, which couples membrane separation and electrochemical advanced oxidation technology, using a first conductive microporous membrane as an anode. The membrane uses the second conductive microporous membrane as the cathode membrane. The anode membrane generates hydroxyl radicals through electrolysis of water, and the cathode membrane generates H ₂ O ₂ through electroreduction of oxygen and further converts it into hydroxyl radicals through Fenton catalyst. The two then cooperate Catalytically generates singlet oxygen to remove refractory organic matter and/or heavy metals from wastewater.

Specifically, the first conductive microporous membrane is used to catalyze the decomposition of H ₂ O by a catalyst under the action of an anode electric field to generate hydroxyl radicals (·OH groups) with strong oxidizing ability, which oxidize and decompose pollutants in wastewater; the second conductive microporous membrane is used to The conductive microporous membrane electrically reduces O ₂ under the action of the cathode electric field to produce H ₂ O ₂ , and then catalyzes the decomposition of H ₂ O ₂ by Fenton catalyst (Fe ²⁺ or Fe ^II ) to produce hydroxyl radicals. The two work together to oxidize and decompose wastewater. contaminants in. In addition, there is a synergistic catalytic effect between the cathode and anode membranes. Specifically, the cathode can electrically reduce O ₂ to produce superoxide anions (O ₂ · ^-groups ), which are converted into singlet oxygen radicals ( ¹ O ₂ ) under the action of the anode. ¹ O ₂ with strong oxidizing ability can also oxidize and decompose pollutants in wastewater. The reactor improves wastewater degradation efficiency and reduces energy consumption through the combined action of various free radicals generated independently by the conductive microporous membranes of the cathode and anode and the synergistic effect of the two electrodes.

Preferably, the first conductive microporous membrane and the second conductive microporous membrane are selected from one of carbon membranes and metal titanium membranes, which are prepared by loading metals, metal oxides or inorganic heteroatoms.

Preferably, the first conductive microporous membrane is selected from one of activated carbon-based carbon membranes loaded with TiO ₂ and metal titanium membranes loaded with TiO ₂ , and the second conductive microporous membrane is selected from the group consisting of activated carbon-based carbon membranes and supported TiO 2 - One of the Fe ⁰ /FeOx activated carbon-based carbon membranes.

Preferably, the wastewater is passed into an electrochemical double membrane reactor, the first conductive microporous membrane is used as the anode membrane, and the second conductive microporous membrane is used as the cathode membrane. By adjusting the membrane filtration flux of the anode membrane and the cathode membrane, to treat wastewater.

Preferably, the membrane filtration flux of the anode membrane and the cathode membrane is adjusted by adjusting the pump speed of the peristaltic pump, and the membrane filtration flux is 10-50L/m ² h;

The effective volume range of the anode membrane and cathode membrane is 20×20×1-400×150×10mm ³ , the electrode spacing range is 15-30mm, the electrolyte is 7.1-14.2g/L sodium sulfate, and the oxygen exposure rate range is 100-400mL/ min, Fenton catalyst is 0.02-0.1mmol/L ferrous sulfate or ferrous chloride.

Preferably, the electrochemical double-membrane reactor includes an electrolysis device. The electrolysis device places the first conductive microporous membrane in the anode membrane chamber and the second conductive microporous membrane in the cathode membrane chamber. The connecting wire is connected to an adjustable DC stabilized power supply.

Preferably, the operating voltage adjustment range of the adjustable DC regulated power supply is 1-3V, and the current is 1-50mA.

Preferably, the wastewater is selected from industrial wastewater containing phenol, ammonia nitrogen, oil or dye, and landfill leachate.

The invention also provides an electrochemical double-membrane reactor, which consists of a blind plate, an anode permeate chamber, an anode permeate outlet, an anode membrane chamber, a feed chamber, a feed liquid inlet, a cathode membrane chamber, and a cathode permeate chamber. Body and cathode permeate outlet composition;

A first conductive microporous membrane is placed in the anode membrane chamber, and a second conductive microporous membrane is placed in the cathode membrane chamber. The cathode membrane chamber and the anode membrane chamber are connected to an adjustable DC regulated power supply via connecting wires respectively. Connect to form an electrolysis device;

The anode permeate outlet and the cathode permeate outlet are connected to their respective peristaltic pumps through pipelines. The peristaltic pump continuously provides negative pressure to pass the material liquid in the material liquid tank through the first conductive microporous membrane and the second conductive microporous membrane respectively. The porous membrane permeates from the feed chamber side to the anode permeate tank and cathode permeate tank sides respectively.

Preferably, the anode permeate outlet and the cathode permeate outlet are respectively connected to the anode permeate tank and the cathode permeate tank through pipelines, and the pipelines are respectively provided with vacuum gauges.

Compared with the existing technology, the advantages and positive effects of the present invention are:

In the electrochemical double-membrane reactor provided by the invention, during the electrochemical process, the anode membrane electrolyzes water to generate hydroxyl radicals; the cathode membrane electrolytically reduces oxygen to generate H ₂ O ₂ , which is further converted into hydroxyl radicals under the action of the Fenton catalyst. ; The cathode and anode membranes synergistically catalyze to produce singlet oxygen. A variety of active substances work together to achieve synergistic removal of refractory organic matter in wastewater, that is, degradation into easily biodegradable small molecules or mineralization into carbon dioxide and water. It can also be used for the oxidation or removal of heavy metals. This reactor device has no membrane and has the advantages of easy operation, high efficiency, and low energy consumption. It can be widely used in the treatment and reuse of industrial wastewater, landfill leachate, etc.

Description of the drawings

Figure 1 is a device diagram of an electrochemical double membrane reactor provided by an embodiment of the present invention;

Reference signs: 1. First conductive microporous membrane 2. Second conductive microporous membrane 3. Adjustable DC regulated power supply 4. Power connection wire 5. Peristaltic pump 6. Vacuum meter 7. Material liquid tank 8. Anode penetration Liquid tank 9, cathode permeate tank 10, blind plate 11, anode permeate chamber 12, anode permeate outlet 13, anode membrane chamber 14, feed chamber 15, feed liquid inlet 16, cathode membrane chamber 17, cathode permeate Liquid chamber 18, cathode permeate outlet;

Figure 2 shows the degradation rates of phenol at different concentrations by three types of electrochemical membrane reactors: electrochemical double membrane reactor, electrocatalytic membrane reactor, and electro-Fenton membrane reactor in Example 4 of the present invention.

Detailed ways

The technical solutions in the embodiments of the present invention will be described clearly and completely below. Obviously, the described embodiments are only some of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts fall within the scope of protection of the present invention.

Example 1

As shown in Figure 1, the electrochemical double membrane reactor consists of a blind plate (10), an anode permeate chamber (11), an anode permeate outlet (12), an anode membrane chamber (13), and a feed chamber (14). , consisting of feed liquid inlet (15), cathode membrane chamber (16), cathode permeate liquid chamber (17), and cathode permeate liquid outlet (18);

The anode membrane chamber (14) contains a first conductive microporous membrane (1), the cathode membrane chamber (17) contains a second conductive microporous membrane (2), and the cathode membrane chamber (17) is connected to The anode membrane chamber (14) is connected to the adjustable DC voltage stabilized power supply (3) via connecting wires (4) respectively to form an electrolysis device;

The anode permeate outlet (12) and cathode permeate outlet (18) are connected to their respective peristaltic pumps (5) through pipelines, and negative pressure is continuously provided through the peristaltic pump (5) to move the material in the material liquid tank (7). The liquid passes through the first conductive microporous membrane (1) and the second conductive microporous membrane (2) from the feed chamber (14) side to the anode permeate tank (8) and cathode permeate tank (9) side respectively. penetration. Moreover, the anode permeate outlet (12) and the cathode permeate outlet (18) are respectively connected to the anode permeate tank (8) and the cathode permeate tank (9) through pipelines, and the pipelines are respectively provided with vacuum gauges ( 6).

The feed liquid of the electrochemical double membrane reactor is 1L of 5mM simulated phenol-containing wastewater. The conductive microporous membrane (activated carbon-based carbon membrane loaded with TiO ₂ ) is used as the anode, and the activated carbon-based carbon membrane is used as the cathode. The effective volume of the cathode and anode is 37× 37×4mm ³ , operating voltage 2.1V, current 11mA, electrode spacing 2.2cm, pH value 3, electrolyte concentration 14.2g/L Na ₂ SO ₄ , Fenton catalyst Fe ₂ SO ₄ concentration 0.02mmol/L, exposure The oxygen rate is 100mL/min. Connect the device as shown in Figure 1. Adjust the pump speed so that the filtration fluxes of the cathode and anode membranes are both 10.1L/m ² h.

Experimental results: The degradation rate of phenol-containing wastewater is 89.2%, and the COD degradation rate is 78.1%.

For comparison, an anode membrane reactor was set up: the anode was a conductive microporous membrane ( _TiO2 -loaded activated carbon-based carbon membrane), the cathode was a stainless steel mesh, and other conditions were consistent with the double-membrane reactor provided in Example 1.

It was found that the treatment efficiency of the double-membrane reactor provided in Example 1 was improved by 61% compared with the traditional anode membrane reactor using a conductive microporous membrane (activated carbon-based carbon membrane loaded with TiO ₂ ) as the anode and a stainless steel mesh as the cathode. , energy consumption is reduced by 28.3%.

Example 2

The feed liquid of the electrochemical double membrane reactor is 0.5L of 1g/L simulated ammonia nitrogen wastewater.

The conductive microporous membrane (activated carbon-based carbon membrane loaded with TiO ₂ ) is used as the anode, and the conductive microporous membrane (activated carbon-based carbon membrane loaded with Fe ⁰ /FeOx) is used as the cathode. The effective volume of the cathode and anode is 37×37×5mm ³ . The operating voltage is 1.6V, the current is 8mA, the electrode distance is 2.5cm, the pH value is 3, the electrolyte concentration is 14.2g/LNa ₂ SO ₄ , the oxygen exposure rate is 100mL/min, connect the device according to Figure 1, and adjust the pump speed to filter the cathode and anode membranes. The flux is 20L/m ² h.

Experimental results: The degradation rate of oily wastewater is 95.6%, and the COD degradation rate is 85.1%.

For comparison, a cathode membrane reactor was set up: the anode was a platinum sheet, the cathode was a conductive microporous membrane (activated carbon-based carbon membrane loaded with Fe ⁰ /FeOx), and other conditions were consistent with the electrochemical double-membrane reactor provided in Example 2.

It was found that the treatment efficiency of the double-membrane reactor provided in Example 2 was improved compared to the traditional cathode membrane reactor using a platinum sheet as the anode and a conductive microporous membrane (activated carbon-based carbon membrane loaded with Fe ⁰ /FeOx) as the cathode. 47%, energy consumption reduced by 16.6%.

Example 3

The feed liquid of the electrochemical double membrane reactor is 0.25L simulated dye wastewater containing 200mg/L methylene blue.

The conductive microporous membrane (metal titanium membrane loaded with TiO ₂ ) is used as the anode, and the effective volume of the anode is 37×37×2mm ³ ; the conductive microporous membrane (activated carbon-based carbon membrane loaded with ^Fe0 /FeOx) is used as the cathode, and the cathode is effective The volume is 37×37×5mm ³ , the operating voltage is 2V, the electrode spacing is 2cm, the current is 5mA, the pH value is 3, the electrolyte concentration is 7.1g/L Na ₂ SO ₄ , the oxygen exposure rate is 100mL/min, and the device is connected according to Figure 1. Adjust the pump speed so that the filtration fluxes of the cathode and anode membranes are both 20L/m ² h.

Experimental results: The chromaticity removal rate of methylene blue wastewater reached 99.9%, and the phenothiazine heterocycle removal rate was 97.0%.

For comparison, an anode membrane reactor was set up: the anode was a conductive microporous membrane (titanium metal membrane supporting _TiO2 ), the cathode was a stainless steel mesh, and other conditions were consistent with the double-membrane reactor provided in Example 3.

It was found that the treatment efficiency of the double-membrane reactor provided in Example 3 was improved by 95% compared to the traditional anode membrane reactor using a conductive microporous membrane (metallic titanium membrane loaded with TiO ₂ ) as the anode and a stainless steel mesh as the cathode. Energy consumption is reduced by 47.2%.

Example 4

The feed liquids of the electrochemical double membrane reactor were 1L of 2mM, 5mM, and 10mM simulated phenol-containing wastewater.

The double-membrane reactor uses a conductive microporous membrane (activated carbon-based carbon membrane loaded with _TiO2 ) as the anode, and a conductive microporous membrane (activated carbon-based carbon membrane loaded with ^Fe0 /FeOx) as the cathode. The effective volume of the cathode and anode is 47×197× 8mm ³ , operating voltage 2.1V, current 150mA, pole spacing 2.2cm, pH value 3, electrolyte concentration 14.2g/L Na ₂ SO ₄ , oxygen exposure rate 100mL/min, connect the device as shown in Figure 1, and adjust the pump speed to The filtration flux of both cathode and anode membranes is 50L/m ² h.

Set up an anode membrane reactor: the anode is a conductive microporous membrane ( _TiO2 -loaded activated carbon-based carbon membrane), the cathode is a stainless steel mesh, and other conditions are consistent with the double-membrane reactor provided in Example 4.

Set up a cathode membrane reactor: the anode is a stainless steel mesh, the cathode is a conductive microporous membrane (activated carbon-based carbon membrane loaded with Fe ⁰ /FeOx), and other conditions are consistent with the electrochemical double membrane reactor provided in Example 4.

Comparing the COD degradation rates and energy consumption of three types of electrochemical membrane reactors for different concentrations of phenol, the results are shown in Figure 2. The results show that under the same conditions, the same volume of phenol with different concentrations is degraded. The phenol degradation rate of the double-membrane reactor is 53.1-67.8% higher than that of the single-stage anode membrane reactor and cathode membrane reactor, while the energy consumption is reduced by 20.9-20.9%. 26.8%.

Claims (10)

1. A wastewater treatment method based on an electrochemical double membrane reactor, characterized in that the electrochemical double membrane reactor couples membrane separation and electrochemical advanced oxidation technology, using the first conductive microporous membrane as the anode membrane, and the second conductive microporous membrane as the anode membrane. The conductive microporous membrane serves as the cathode membrane. The anode membrane generates hydroxyl radicals through electrolysis of water. The cathode membrane generates H ₂ O ₂ through electroreduction of oxygen and further converts it into hydroxyl radicals through Fenton catalyst. The two then cooperate to catalyze the generation of singlet oxygen. , to achieve the removal of refractory organic matter and/or heavy metals in wastewater. 2. The wastewater treatment method according to claim 1, characterized in that the first conductive microporous membrane and the second conductive microporous membrane are selected from one of carbon membranes and metal titanium membranes, which are loaded with metal, Prepared from metal oxides or inorganic heteroatoms. 3. The wastewater treatment method according to claim 2, wherein the first conductive microporous membrane is selected from one of a TiO-loaded activated carbon-based carbon membrane and a TiO _{- loaded} titanium metal membrane, and the The second conductive microporous membrane is selected from one of activated carbon-based carbon membranes and Fe ⁰ /FeOx-loaded activated carbon-based carbon membranes. 4. The wastewater treatment method according to any one of claims 1 to 3, characterized in that the wastewater is passed into an electrochemical double membrane reactor, the first conductive microporous membrane is used as the anode membrane, and the second conductive microporous membrane is used as the anode membrane. The porous membrane serves as a cathode membrane and treats wastewater by adjusting the membrane filtration flux of the anode membrane and cathode membrane. 5. The wastewater treatment method according to claim 4, characterized in that the membrane filtration flux of the anode membrane and the cathode membrane is adjusted by adjusting the pump speed of the peristaltic pump, and the membrane filtration flux is 10-50L/m ² h ; The effective volume range of the anode membrane and cathode membrane is 20×20×1-400×150×10mm ³ , the electrode spacing range is 15-30mm, the electrolyte is 7.1-14.2g/L sodium sulfate, and the oxygen exposure rate range is 100-400mL/ min, Fenton catalyst is 0.02-0.1mmol/L ferrous sulfate or ferrous chloride. 6. The wastewater treatment method according to claim 4, characterized in that the electrochemical double-membrane reactor includes an electrolysis device, and the electrolysis device places a first conductive microporous membrane in an anode membrane chamber. Two conductive microporous membranes are placed in the cathode membrane chamber and are connected to an adjustable DC voltage stabilized power supply via connecting wires. 7. The wastewater treatment method according to claim 6, characterized in that the operating voltage adjustment range of the adjustable DC regulated power supply is 1-3V, and the current is 1-150mA. 8. The wastewater treatment method according to any one of claims 1 to 7, characterized in that the wastewater is selected from the group consisting of industrial wastewater containing phenol, ammonia nitrogen, oil or dye, and landfill leachate. 9. Electrochemical double membrane reactor, characterized in that it consists of a blind plate, an anode permeate chamber, an anode permeate outlet, an anode membrane chamber, a feed chamber, a feed liquid inlet, a cathode membrane chamber, and a cathode permeate chamber. , cathode permeate outlet composition; A first conductive microporous membrane is placed in the anode membrane chamber, and a second conductive microporous membrane is placed in the cathode membrane chamber. The cathode membrane chamber and the anode membrane chamber are connected to an adjustable DC regulated power supply via connecting wires respectively. , constitute an electrolysis device; The anode permeate outlet and the cathode permeate outlet are connected to their respective peristaltic pumps through pipelines. The peristaltic pump continuously provides negative pressure to pass the material liquid in the material liquid tank through the first conductive microporous membrane and the second conductive microporous membrane respectively. The porous membrane permeates from the feed chamber side to the anode permeate tank and cathode permeate tank sides respectively. 10. The electrochemical double membrane reactor according to claim 9, characterized in that the anode permeate outlet and the cathode permeate outlet are also connected to the anode permeate tank and the cathode permeate tank respectively through pipelines, and the pipelines are Vacuum gauges are provided respectively.