Patent Application
20240336508
This patent application claims the benefit and priority of Chinese Patent Application No. 202310374819.3 filed with the China National Intellectual Property Administration on Apr. 10, 2023, the disclosure of which is incorporated by reference herein in its entirety as part of the present application.
The present disclosure belongs to the technical field of reverse osmosis concentrated brine (ROC) treatment, and specifically relates to a method and a system for resource treatment of an ROC by bipolar membrane electrodialysis.
With the development of industry in China, industrial water consumption is increasing annually, the discharge of wastewater increases thereupon, with a drainage composition becoming more and more complex. In particular, a large portion of high-salt wastewater is generated in the fields of coal conversion, thermal power plant desulfurization, printing and dyeing, papermaking, as well as extraction and processing of petroleum and natural gas. This is in sharp contrast to the current serious pollution of water resources and the increasingly strict standards for industrial wastewater treatment and reuse in China, and has resulted in an increasingly prominent contradiction between water supply and demand, thus seriously restricting the rapid and healthy development of the national economy. Therefore, high-salt wastewater treatment and resource utilization have become an inevitable choice for environmental protection and sustainable utilization of water resources. A sustainable option for treating high-salt wastewater is the development of “zero emission” waste liquid systems. Early zero-emission systems mainly depend on thermal evaporation technology, and thus show extremely high energy consumption. In order to reduce treatment costs, reverse osmosis technology is widely used in the treatment of high-salt wastewater. The reverse osmosis technology could obtain about 70% of high-quality recycled water from high-salt wastewater, and exhibits desirable environmental and economic benefits. However, this technology also produces about 30% of reverse osmosis concentrated brine (ROC). The ROC has a total dissolved solid (TDS) content of generally 10 g/L to 50 g/L, and mainly contains inorganic cations such as sodium, potassium, calcium, magnesium, and silicon ions, as well as inorganic anions such as chloride, sulfate, and nitrate ions. In addition, heavy metals are contained in the ROC, mainly including arsenic, barium, cadmium, lead, copper, and zinc. As another feature, ROC contains a wide variety of organic matter species, which are difficult to biochemically degrade, thereby showing a high chemical oxygen demand (COD) (200 mg/L to 4,000 mg/L). Direct discharge of ROC without treatment could cause serious pollution to the water environment. As a result, resource treatment of the ROC based on environmental protection requirements and “zero emission” of wastewater has become an important part of current water treatment.
At present, the treatment and disposal technologies for ROC mainly include natural evaporation, thermal evaporation, membrane separation, and direct emission reduction (such as recovery, discharge of surface water or sewage treatment system, and deep well injection). However, conventional ROC treatment or disposal technologies and methods have limitations or shortcomings. Their purpose is mainly to reduce the impact of ROC by reducing the volume or pollution load of ROC, but does not essentially achieve “zero emission” of the ROC. In addition, according to research data, a cost of ROC emissions accounts for approximately 20% to 35% of a total treatment costs, resulting in a waste of water resources and energy consumption.
CN101928088B discloses “a method for treating ROC in petrochemical enterprises.” This method adopts a treatment process of “nanofiltration+alkali adjustment+air flotation magnesium removal+calcium removal+microfiltration+neutralization+reverse osmosis+multi-effect evaporation+drying”; produced water during the treatment can be returned to a reverse osmosis system of the previous level for treatment and reuse; and a residue obtained during the treatment can be collected and disposed together. This method could reduce the pollution of reverse osmosis membrane and improve the treatment efficiency, and has certain social and economic benefits. However, this method still cannot achieve zero emissions, and has high costs and cumbersome procedures during the treatment, resulting in a low efficiency.
CN106396234A discloses “a zero-emission treatment method of ROC”. This method is to conduct nanofiltration on pretreated ROC to obtain nanofiltration concentrate rich in SO42− and Mg2+ and nanofiltration penetrating liquid containing Na+, Cl−, NO3−, K+, and Ca2+. After concentration, the nanofiltration concentrate is mixed with the penetrating liquid to precipitate, thereby removing CaSO4, and then subjected to further separation by crystallization. the nanofiltration permeate is subjected to processes such as medium-pressure reverse osmosis, multi-effect evaporation, and multi-effect membrane distillation to concentrate such that various inorganic salts contained therein are at a nearly saturated state, and then fresh water resources therein are recovered. This method recovers fresh water and solid salts, and eliminates the pollution of ROC, but adopts evaporation crystallization with high cost, and produces solid miscellaneous salts that are difficult to separate out and may also generate secondary pollution.
CN109081488A discloses “a method and system for resource utilization of industrial concentrated brine”. This method involves mixing industrial concentrated salt water with alkaline solution and removing precipitates through a microfiltration system. After passing through a nanofiltration system, a solution a containing mainly monovalent salts and a solution b containing mainly divalent salts are obtained. The solution a is concentrated by a reverse osmosis system and then evaporated and crystallized to obtain an industrial sodium chloride product, while the solution b is further subjected to resin exchange to remove calcium and magnesium ions and then electrolyzed to obtain an alkali solution and a sulfuric acid solution. This process has an ingenious system design, although recycling the electrolyzed alkaline solution can reduce the dosing cost of the system, obtaining the industrial sodium chloride product through high-energy-consumption evaporation crystallization is not conducive to the long-term economic benefits of enterprises. Even if the quality of the sodium chloride produced could meet the requirements of first-class industrial products, there has been an excessive domestic production of sodium chloride. Accordingly, most of the industrial sodium chloride product produced with zero emissions is sold at ultra-low prices, which is not conducive to practical applications.
The above references could process ROC better and also recover useful resources in the ROC. However, the traditional methods of recycling salt have high energy consumption, large investment, and poor efficiency, while the recycled industrial salt is also difficult to sell. Moreover, these methods involve complex processes, and errors in any link could directly affect the quality of the crystallized salt. In view of this, there is an urgent need to explore an efficient and low-cost resource treatment method.
The present disclosure aims to overcome the problems and defects in the existing traditional technology for treating ROC, and provides a method for resource treatment of an ROC by a bipolar membrane electrodialysis device. The present disclosure solves the problems of high treatment cost and great harm of crystallized miscellaneous salts produced by the existing ROC treatment technology, and the recovered acid and alkali in the present disclosure are reused in the pretreatment, or further processed and sold. In the present disclosure, COD is removed from wastewater using an electro-Fenton technology, which could extend a service life of the membrane while reducing the risk of membrane fouling and clogging.
The present disclosure is achieved by the following technical solutions.
On one hand, the present disclosure provides a method for resource treatment of an ROC by bipolar membrane electrodialysis, including the following steps:
In some embodiments of the present disclosure, in step (a), the calcium-magnesium precipitant includes or consists of NaOH and Na2CO3, the NaOH is added in an amount of 0.1% to 2.0%, and the Na2CO3 is added in an amount of 0.2% to 0.6%; and after a precipitation is conducted for 20 min to 50 min, a resulting system is adjusted to a pH value of 11 to 12.
In some embodiments of the present disclosure, in step (b), the diatomaceous earth has a particle size of 6 μm to 25 μm and is added in an amount of 0.8 g/L to 1.0 g/L; the filter membrane is formed on a surface of a filter element by bridging after continuously cycling for 5 min to 10 min, and the ROC after removing hardness is introduced by switching a valve to continuously intercept the precipitate.
In some embodiments of the present disclosure, in step (c), the pH adjuster is derived from the acid and the alkali regenerated from the resource treatment of the ROC by the bipolar membrane electrodialysis, and a residence time in step (c) is in a range of 10 min to 20 min; and the resulting filtrate is adjusted to have a pH value of 2 to 4.
In some embodiments of the present disclosure, in step (d), the electro-Fenton reaction device has a voltage of 10 V to 30 V, a pH value of 2.5 to 3.5, and an electrolysis time of 20 min to 100 min.
In some embodiments of the present disclosure, in step (e), a microporous filter membrane in the PP microporous filter has a pore size of 0.2 μm to 1.0 μm.
In some embodiments of the present disclosure, in step (f), the bipolar membrane electrodialysis device has a flow rate controlled at 60 L/h to 240 L/h and a direct current (DC) voltage applied to each group of membranes at 1 V to 3 V.
In some embodiments of the present disclosure, the bipolar membrane electrodialysis is performed through the following steps
On the other hand, the present disclosure further provides a system for resource treatment of an ROC by bipolar membrane electrodialysis applicable to the method as described above, including a hardness removal device, a diatomaceous earth filter, a pH adjusting tank, the electro-Fenton reaction device, the PP microporous filter, and the bipolar membrane electrodialysis device, all of which are sequentially communicated, wherein a water outlet pipe of the hardness removal device and a water outlet pipe of the pH adjusting tank each are in communication with the bipolar membrane electrodialysis device.
In some embodiments of the present disclosure, the bipolar membrane electrodialysis device adopts a bipolar membrane electrodialysis membrane stack having a “BP-A-C” configuration-based one-cavity and multi-chamber plate frame structure, and includes a salt chamber, an alkali chamber, an acid chamber, and an electrode chamber, wherein the salt chamber is communicated with the feed liquid storage tank, a liquid storage tank, and a dilute liquid storage tank, respectively; the alkali chamber is communicated with the alkali storage tank, a deionized water replenishing tank, and an alkali product storage tank, respectively; the acid chamber is communicated with the acid storage tank, the deionized water replenishing tank, and an acid product storage tank, respectively; and the electrode chamber communicates with the electrode liquid storage tank to form a circulation loop.
The ROC in the ROC storage tank passes through the hardness removal device to remove hardness, is filtered with the diatomaceous earth filter, adjusted to a suitable pH value in the pH adjusting tank, oxidized in the electro-Fenton reaction device, subjected to fine filtration through the PP microporous filter, and then electrolyzed by the bipolar membrane electrodialysis device to generate acid and alkali.
By means of the foregoing technical solution, embodiments of the present disclosure has the following advantageous effects:
The accompanying drawings described here are provided for further understanding of the present disclosure, constitute a part of this disclosure, but do not constitute inappropriate limitations to the present disclosure.
In
In
The present disclosure is described in detail below in conjunction with the accompanying drawings and specific examples. Exemplary examples and description of the present disclosure are intended to explain the present disclosure herein, but are not intended to limit the present disclosure.
As shown in
The PP microporous filter 6 is made of polytetrafluoroethylene, and has a filter element length of 500 mm and a pore size of 0.22 μm.
The inert anode and cathode in an electrolytic cell of the electro-Fenton reaction device 5 each adopt a titanium electrode, a titanium alloy electrode, or a graphite electrode, and each have a flat, columnar, or porous configuration.
The ROC in the ROC storage tank 1 passes through the hardness removal device 2 to remove hardness, is filtered through the diatomaceous earth filter 3, adjusted to a suitable pH value in the pH adjusting tank 4, oxidized in the electro-Fenton reaction device 5, subjected to fine filtration with the PP microporous filter 6, and then electrolyzed in the bipolar membrane electrodialysis device 7 to generate acid and alkali.
An electrode liquid storage tank 9, an acid storage tank 10, a liquid storage tank 11, and an alkali storage tank 12 are in cyclic communication with the bipolar membrane electrodialysis membrane stack 8, and the bipolar membrane electrodialysis membrane stack 8 is connected to the DC power supply 15. An outlet side of the storage tank is connected to a magnetic pump 13, and an inlet side thereof is connected to the bipolar membrane electrodialysis membrane stack 8. An inlet side of the magnetic pump 13 is connected to the storage tank, and an outlet side thereof is connected to the bipolar membrane electrodialysis membrane stack 8, with a rotameter 14 and a valve 16 that are disposed therebetween. An inlet side of the bipolar membrane electrodialysis membrane stack 8 is connected to the magnetic pump 13; an outlet side thereof is connected to the storage tank, and an outlet end thereof is provided with a cooler to control a solution temperature. A distribution box is connected to the magnetic pump 13 and a DC power supply 15, and the DC power supply 15 is connected to positive and negative electrodes of the bipolar membrane electrodialysis membrane stack 8.
As shown in
The bipolar membrane electrodialysis membrane stack 8 is in a “BP-A-C” configuration-based one-cavity and multi-chamber plate frame structure, and includes a salt chamber, an alkali chamber, an acid chamber, and an electrode chamber; the salt chamber is communicated with a feed liquid storage tank 17, a liquid storage tank 11, and a dilute liquid storage tank 21, respectively; the alkali chamber is communicated with an alkali storage tank 12, a deionized water replenishing tank 18, and an alkali product storage tank 21, respectively; the acid chamber is communicated with an acid storage tank 10, the deionized water replenishing tank 18, and an acid product storage tank 19, respectively; and the electrode chamber communicates with the electrode liquid storage tank 9 to form a circulation loop.
The feed liquid storage tank 17 and the deionized water replenishing tank 18 are connected to the salt chamber and the acid/alkali chambers of the bipolar membrane electrodialysis membrane stack 8, respectively, and the flow rate is controlled by the magnetic pump 13 and the rotameter 14 provided on a circulation pipeline. An acid chamber output liquid and an alkali chamber output liquid are communicated with the acid storage tank 10 and the alkali storage tank 12, respectively, and acid and alkali circulation loops are formed through circulation pipeline(s) and the bipolar membrane electrodialysis membrane stack 8, respectively. The electrode liquid storage tank 9 is communicated with the bipolar membrane electrodialysis membrane stack 8, thereby forming an electrode liquid circulation loop. A salt chamber output liquid is communicated with the liquid storage tank 11, and a feed liquid circulation loop is formed through circulation pipeline(s) and the bipolar membrane electrodialysis membrane stack 8. A product acid in the acid storage tank 10 and a product alkali in the alkali storage tank 12 are discharged to the acid product storage tank 19 and the alkali product storage tank 21 through the valve 16, respectively. A dilute liquid in the liquid storage tank 11 is discharged to the dilute liquid storage tank 20 through the valve.
The magnetic pump 13, valve 16, and rotameter 14 are provided on each circulation pipeline.
As shown in
Step a: the ROC is introduced into the hardness removal device 2, and a reagent is added thereto, and a resulting mixture is mixed by stirring, in which the hardness removal device is a mixing reaction tank, NaOH and Na2CO3 are added thereto as the calcium-magnesium precipitant (i.e., the reagent), the NaOH is added in an amount of 0.1% to 2.0%, and the Na2CO3 is added in an amount of 0.2% to 0.6%; and a resulting system after removing hardness is adjusted to a pH value of 11 to 12 after the precipitation is conducted for 20 min to 50 min.
The reagent (i.e., the calcium-magnesium precipitant) fully reacts with ROC to form insoluble calcium carbonate and magnesium hydroxide precipitates to remove incompletely precipitated calcium and magnesium, thereby removing not less than 99% of hardness.
Step b: a resulting mixture after removing hardness in step a is filtered through the diatomaceous earth filter 3, which is realized by forming a filter membrane on a surface of diatomaceous earth, so as to intercept an organic matter and a precipitate.
The diatomaceous earth has a particle size of 6 μm to 25 μm, and the diatomaceous earth is added in an amount of 0.8 g/L to 1.0 g/L; a circulation pump is turned on to send the prepared slurry into the filter. Depending on the pressure of a water pump (working pressure at 0.3 MPa to 0.6 MPa), a part of the diatomaceous earth is retained by the filter element and adheres to its surface. Generally, after 5 min to 10 min of continuous circulation, bridges are formed on the surface of the filter element to form a filter membrane. The valve is switched to introduce the ROC after removing hardness, and the precipitate is continuously intercepted. When the pump has an outlet pressure of 0.65 MPa and a flow rate lower than 1.5 m3/h, the cycle ends to enter a backwashing stage.
Step c, a filtrate filtered through the diatomaceous earth filter 3 is introduced into the pH adjusting tank 4, and hydrochloric acid or sulfuric acid is added into the pH adjusting tank 4 to adjust the filtrate to be acidic.
The pH adjusting tank 4 is configured to continuously adjust and stabilize the pH value of the filtrate passing through the diatomaceous earth filter. A pH adjuster used is derived from the acid and the alkali regenerated from the resource treatment of the ROC by the bipolar membrane electrodialysis, and a residence time in the pH adjusting tank 4 is in a range of 10 min to 20 min; and the acidic filtrate after acid treatment in the pH adjusting tank 4 has an optimal pH value of 2 to 4.
Step d: the acidic filtrate treated in the pH adjusting tank enters the electro-Fenton reaction device 5, and in an acidic environment Fe2+ which is produced by the plate itself after energization reacts rapidly with H2O2 to generate highly active hydroxyl radicals (·OH), wherein the ·OH could continuously and effectively cause COD, ammonia nitrogen and other pollutants to directly lose their electrons and be oxidized, such that the COD removal rate is not less than 97%.
The inert anode and cathode of an electrolytic cell of the electro-Fenton reaction device 5 may be titanium electrode(s), titanium alloy electrode(s), or graphite electrode(s), and their configuration may be flat, columnar or porous. The electrolysis is conducted by a regulated DC power supply with a voltage of 10 V to 30 V at a pH value of 2.5 to 3.5 for 20 min to 100 min.
The electro-Fenton reaction device 5 is provided with two reaction zones, which are a reduction internal electrolysis reaction tank and a Fenton oxidation reaction tank. The reaction tanks are separately provided with a filler, and the device has a dimension: 1000×600×1800 (length×width×height, mm). The principle of device is to electrolyze the ROC entering the reduction internal electrolysis reaction tank under the condition of energization. The ROC has a residence time of 0.5 h to 1 h in the reduction internal electrolysis reaction tank, and has a residence time of 0.5 h to 2 h in the Fenton oxidation reaction tank. O2 is reduced by electrons at the cathode to generate H2O2, and H2O2 further reacts rapidly with Fe2 in the solution to generate active hydroxyl radicals (·OH). The active ·OH reacts with macromolecular organic matters in the Fenton oxidation reaction tank, thereby destroying a molecular structure of the organic matters, such that the refractory organic matters are converted into CO2, H2O, and small organic molecules to obtain degraded wastewater.
Step e: an effluent from the electro-Fenton reaction device 5 is subjected to fine filtration with the PP microporous filter 6, wherein a microporous filter membrane in the PP microporous filter 6 has a pore size of 0.2 μm to 1.0 μm, to obtain a treatment liquid that meets the requirements for entering the bipolar membrane electrodialysis modules.
Step f: the filtrate after fine filtration with the PP microporous filter 6 is introduced into the bipolar membrane electrodialysis device 7. Na+, K+, NH4+, SO42−, Cl−, NO3− in the raw material chamber pass through the cation exchange membrane and anion exchange membrane to enter the alkali chamber and acid chamber under the action of an external electric field, respectively, and then combines with H+ and OH− dissociated from the water by bipolar membrane to generate the acid and alkali.
The bipolar membrane electrodialysis device 7 is in a “BP-A-C” configuration-based one-cavity and multi-chamber plate frame structure, which consists of a membrane stack, a magnetic pump, a liquid storage tank, a distribution box, and a regulated DC power supply. The membrane stack is composed of an electrode region, an anion exchange membrane, a cation exchange membrane, a bipolar membrane, and a compression device. In the membrane stack, a number of membrane groups could be freely increased or decreased with the amount of solution to be treated, a flow rate is controlled at 60 L/h to 240 L/h, and a DC voltage applied to each group of membranes is in a range of 1 V to 3 V.
The electrode region adopts a ruthenium-coated titanium electrode, the anion and cation exchange membranes are both a perfluorosulfonic acid membrane (Nafion™), and the bipolar membrane is a BP-1 bipolar membrane. The bipolar membrane electrodialysis includes/consists of the following steps:
In some embodiments, the ROC includes the following main anions: Cl− (19.8 g/L), SO42− (18.5 g/L), and NO3− (1.2 g/L), and the following main cations: Na+ (23.2 g/L), NH4+ (3.9 g/L), Ca2+ (2.7 g/L), Mg2+ (1.4 g/L), and K+ (0.8 g/L).
f4, under the action of a DC electric field, dissociating H2O in an interface layer of the bipolar membrane into H+ and OH− which migrate to the acid chamber and alkali chamber, respectively, where the H+ and negatively-charged salt ions passing through the anion exchange membranes form mixed acid in the acid chamber; and OH− and positively-charged salt ions passing through the cation exchange membranes form mixed alkali in the alkali chamber; and
f5, by setting the salt chamber, acid chamber, and alkali chamber in a “continuous operation” mode, controlling inlet and outlet flow rates of the acid chamber, alkali chamber, and salt chamber, as well as a circulation flow rate of the solution in each chamber in the membrane stack; wherein under the condition that an acid/alkali concentration reaches a certain value, the prepared acid/alkali is continuously pumped into the acid/alkali storage tank, while deionized water is also continuously pumped into a bipolar membrane electrodialysis (BMED) membrane stack; under the condition that a concentration of the feed liquid drops to a certain value, a new feed liquid is introduced immediately for replacement to ensure the continuous preparation of acid and alkali.
A principle of an embodiment of the present disclosure is shown in
The present disclosure is further described below in conjunction with different examples.
ROC had a water quality shown in Table 1 and was treated through the following steps.
(1) The ROC was introduced into a hardness removal device 2, and a softening agent was added, wherein the softening agent consisted of 0.2% NaOH and 0.3% Na2CO3, and the NaOH and Na2CO3 were added gradually with stirring. The stirring was conducted at 100 r/min for 1 h. After leaving to stand, a resulting mixture was filtered and the precipitate was filtered out, and a pH value of a resulting filtrate was adjusted to 11 to 12 to remove incompletely precipitated calcium and magnesium, thus realizing a hardness removal rate of not less than 99%. The agent reacted fully with ROC to form insoluble calcium carbonate and magnesium hydroxide precipitates. The water quality indicators of an effluent obtained from the hardness removal unit were shown in Table 2.
(2) The effluent from step (1) was introduced into a diatomaceous earth filter 3, and a prepared 0.9 g/L diatomaceous earth slurry was added into the filter through a circulating pump; relying on a 0.6 MPa pressure of the circulation pump, a part of the diatomaceous earth could bridge on a surface of the filter to form a filter membrane, generally by 8 min of continuous circulation; and a valve was switched to introduce the ROC after hardness removal, such that the precipitate and some organic matters were continuously intercepted. The water quality indicators of an effluent from the primary filtration unit were shown in Table 2.
(3) The filtrate obtained in step (2) was introduced into a pH adjusting tank 4 with a residence time of 10 min; and hydrochloric acid or sulfuric acid was added thereto to adjust the filtrate to be acidic, with a pH value of 4. The water quality indicators of an effluent from the pH adjusting unit were shown in Table 2.
(4) The acidic filtrate obtained in step (3) was pumped into an electro-Fenton reaction device 5, and the ROC in a reduction internal electrolysis reaction tank was subjected to electrolysis under the condition of energization at a voltage of 15 V with a pH value of 3.5 for 80 min. O2 was reduced by electrons at the cathode to generate H2O2, and the H2O2 further reacted rapidly with Fe2+ in the solution to generate active hydroxyl radicals (·OH). The active ·OH reacted with macromolecular organic matters in the Fenton oxidation reaction tank, thereby destroying a molecular structure of the organic matters, such that the refractory organic matters were converted into CO2, H2O, and small organic molecules, thereby reducing the COD to not more than 40 mg/L. The water quality indicators of an effluent from the electro-Fenton unit were shown in Table 2.
(5) The effluent obtained in step (4) was then subjected to fine filtration with a PP microporous filter 6 to obtain a treatment liquid that met the requirements for entering the bipolar membrane electrodialysis modules. The water quality indicators of an effluent passing through the microporous fine filtration unit were shown in Table 2.
(6) The effluent obtained in step (5) was introduced into a salt chamber of a bipolar membrane electrodialysis membrane stack 8, wherein a feed liquid chamber, an acid chamber, and an alkali chamber adopted the “intermittent” operation mode, as shown in
The acid concentration of the acid product was 0.79 mol/L, the alkali concentration of the alkali product was 0.74 mol/L, the average current efficiency was 77%, the energy consumption was 2.2 kwh/kg sodium hydroxide, and the desalination rate of ROC was 97.61%.
ROC had a water quality shown in Table 1 and was treated through the following steps:
The acid concentration of the acid product was 1.24 mol/L, the alkali concentration of the alkali product was 1.18 mol/L, the average current efficiency was 72%, the energy consumption was 2.8 kwh/kg sodium hydroxide, and the desalination rate of ROC was 92.6%.
ROC had a water quality shown in Table 1 and was treated through the following steps:
The acid concentration of the acid product was 2.1 mol/L, the alkali concentration of the alkali product was 1.96 mol/L, the average current efficiency was 61%, the energy consumption was 4.5 kwh/kg sodium hydroxide, and the desalination rate of ROC was 81.5%.
It can be seen from the above examples that the ROC could be treated by the method of the present disclosure, and the treated ROC has a COD≤3%, a content of calcium and magnesium ions ≤1%, and a salt content ≤1.3%. In view of the problems of traditional technology in treating ROC such as long process flow, great technical difficulty, complex treatment system, and high energy consumption cost, the present disclosure proposes to directly convert most of the ROC into acid and alkali by bipolar membrane electrodialysis without evaporation and crystallization, thus greatly reducing evaporation. Moreover, the bipolar membrane electrodialysis device has low space requirements and compact equipment, and could create certain economic benefits while reducing environmental harm. In addition, the excellent characteristics and economic advantages of BMED may provide new strategies for building desirable desalination systems, which may be an inevitable requirement and an important development direction for efficient utilization of water resources. Therefore, the method of the present disclosure is an effective solution with sustainable resource recycling, low energy consumption cost, and environmental friendliness.
The present disclosure is not limited to the foregoing examples. On the basis of the technical solution disclosed in the present disclosure, a person skilled in the art could make some substitutions and transformations for some of the technical features according to the technical disclosure without involving an inventive effort, and such substitutions and transformations fall within the scope of the present disclosure.
| Number | Date | Country | Kind |
|---|---|---|---|
| 202310374819.3 | Apr 2023 | CN | national |
