Experimental device, experimental method and island fresh water self-maintaining method

Abstract

The invention discloses an experimental device, an experimental method and an island fresh water self-maintaining method, and belongs to the technical field of seawater resource recycling. The device comprises: a membrane module mechanism having a pole chamber, a volume-variable salt chamber, a volume-variable acid chamber and a volume-variable alkali chamber; the liquid circulating mechanism comprises a pole container used for forming a circulating loop with the pole chamber, a salt container used for forming a circulating loop with the salt chamber, an acid container used for forming a circulating loop with the acid chamber and an alkali container used for forming a circulating loop with the alkali chamber; the power supply mechanism is electrically connected with the anode and the cathode in a voltage-adjustable manner; and the data acquisition mechanism is used for acquiring data of the device. According to the device, the volume of the acid chamber, the volume of the alkali chamber, the volume of the salt chamber, the voltage, the acid concentration and the alkali concentration can be adjusted, the current, the electrolysis duration, the volume of the acid solution and the volume of the alkali solution and the concentration of the acid solution and the concentration of the alkali solution are collected through the data collection mechanism, and the optimal parameters for balancing energy consumption and current efficiency are determined.

Description

Technical Field

[0001] The invention relates to the technical field of seawater resource reuse, and in particular to an experimental device, an experimental method and a method for self-maintaining fresh water on an island. Background Art

[0002] In recent years, bipolar membrane electrodialysis (BMED) technology has made significant progress in the fields of water treatment and resource recycling, and has become an important means of producing acids and alkalis. Bipolar membrane electrodialysis is a technology that combines ion-selective membranes and electrochemical reactions. It is mainly composed of cationic membranes, anionic membranes and bipolar membranes. When current passes through the membrane system, cations migrate to the cathode region through the cationic membrane, while anions migrate to the anode region through the anionic membrane. The presence of the bipolar membrane causes water molecules to undergo electrolysis reactions at the interface of the membrane, producing hydrogen ions ( ) and hydroxide ions ( ), and then synthesize acid or base. In areas lacking fresh water resources such as islands, bipolar membrane electrodialysis can use seawater to desalinate water and extract valuable ions. By precisely controlling the current, by-products such as acid and base can be obtained while achieving water treatment, further realizing efficient utilization of resources.

[0003] Existing research on the systematic study of the impact of operating conditions of bipolar membrane electrodialysis when treating different types of seawater is still insufficient, especially in the research on treating actual seawater; although some studies have explored the basic principles of bipolar membrane electrodialysis and its potential application in seawater desalination, most of the studies mainly focused on testing using simulated seawater under laboratory conditions, which is significantly different from the complexity of actual seawater.

[0004] Moreover, although some existing methods disclose some methods of preparing acid and alkali by bipolar membrane electrodialysis, these methods are specific methods of preparing acid and alkali, and do not propose how to develop the optimal method with the lowest energy consumption for different seawater. The root cause is that the energy consumption of bipolar membrane electrodialysis is mainly affected by the initial membrane resistance, which is in turn affected by multiple parameters such as pH value, chamber volume ratio, and voltage. Simple bipolar membrane electrodialysis devices have many uncertain factors and data errors, and it is impossible to explore the influence of multiple parameters on the bipolar membrane electrodialysis treatment process to determine the most appropriate parameters for balancing energy consumption and current efficiency. Summary of the invention

[0005] The present invention provides an experimental device, an experimental method and a method for self-sustaining freshwater on an island, aiming to solve the technical problem in the prior art that it is impossible to simulate and study the parameters affecting the initial membrane resistance to determine the optimal parameters for balancing energy consumption and current efficiency.

[0006] The first aspect of the present invention provides an experimental device, comprising:

[0007] A membrane group structure, comprising an anode, a cathode and a plurality of membrane bodies, wherein a polar chamber, a salt chamber with a variable volume, an acid chamber with a variable volume and an alkali chamber with a variable volume are separated between the anode and the cathode by the plurality of membrane bodies;

[0008] A liquid circulation mechanism, comprising a pole container for forming a circulation loop with the pole chamber, a salt container for forming a circulation loop with the salt chamber, an acid container for forming a circulation loop with the acid chamber, and an alkali container for forming a circulation loop with the alkali chamber;

[0009] A power supply mechanism, electrically connected to the anode and the cathode, and used to adjust the voltage between the anode and the cathode;

[0010] The data collection mechanism is used to collect the current of the experimental device, the electrolysis time, the volume of the acid solution and the alkaline solution, and the concentration of the acid solution and the alkaline solution.

[0011] In some embodiments of the first aspect, the volume of the salt chamber, the volume of the acid chamber, and the volume of the base chamber change spontaneously.

[0012] The second aspect of the present invention provides an experimental method, which uses the experimental device described in the first aspect;

[0013] The following steps are involved:

[0014] S1, introducing an electrolyte solution into the electrode chamber, introducing seawater into the salt chamber, and introducing an acid solution and an alkaline solution into the acid chamber and the alkaline chamber, respectively;

[0015] S2, the power supply mechanism applies a preset voltage to the membrane group mechanism and performs electrodialysis to obtain a product; wherein the data collection mechanism collects electrodialysis process data;

[0016] S3, changing the parameters of the preset voltage, the parameters of the acid solution, the parameters of the alkaline solution, the volume of the salt chamber, the volume of the acid chamber, and the volume of the alkaline chamber within a preset range, and repeating S1 to S3 until a preset number of parameters within the preset range are executed;

[0017] S4, based on the electrodialysis process data, determining optimal parameters of a preset voltage, an acid solution, an alkaline solution, a salt chamber volume, an acid chamber volume, and an alkaline chamber volume according to preset conditions.

[0018] In some embodiments of the second aspect, the preset range of the concentration of the acid solution introduced into the acid chamber is 0-0.25 mol / L; the preset range of the concentration of the alkali solution introduced into the alkali chamber is 0-0.25 mol / L.

[0019] In some embodiments of the second aspect, a preset range of the volume ratio of the salt chamber to the acid chamber is 1:1-4:1; a preset range of the volume ratio of the salt chamber to the alkali chamber is 1:1-4:1.

[0020] In some embodiments of the second aspect, the preset range of the preset voltage applied by the power supply mechanism to the membrane group mechanism is 10-18V.

[0021] In some embodiments of the second aspect, the electrolyte solution is a sulfate solution, and the concentration of the sulfate solution is 0.02-0.07 mol / L.

[0022] In some embodiments of the second aspect, the solution flow rate of the electrode chamber, the salt chamber, the acid chamber and the base chamber is 20-40 L / h.

[0023] In some embodiments of the second aspect, between step S1 and step S2, the following steps are further included:

[0024] The power supply mechanism applies a bubble removal voltage to the membrane group mechanism, so that the solution in the experimental device circulates for a preset time to remove bubbles in the experimental device.

[0025] The third aspect of the present invention provides a method for self-sustaining island freshwater, which applies the optimal parameters obtained by the experimental method described in the second aspect, and performs electrodialysis treatment based on the optimal parameters to obtain a product.

[0026] In some embodiments of the third aspect, the seawater is island native seawater, the preset voltage is 16V, the concentration of the acid solution passed into the acid chamber is 0.05mol / L, the concentration of the acid solution passed into the alkali chamber is 0.05mol / L, the volume ratio of the salt chamber to the acid chamber is 2:1, the volume ratio of the salt chamber to the alkali chamber is 2:1, and the electrolyte solution is 0.02mol / L sodium sulfate.

[0027] It can be seen from the above technical solutions that the present invention has the following advantages:

[0028] The present embodiment provides an experimental device. Since the present experimental device is provided with a plurality of salt chambers, acid chambers and alkali chambers with variable volumes, and the power supply mechanism is electrically connected to the anode and the cathode in an adjustable voltage manner, the preset voltage, acid concentration and alkali concentration can be adjusted according to research needs, and the volume of the acid chamber, the volume of the alkali chamber and the volume of the salt chamber can be changed. The user can collect the current, electrolysis time, the volume of the acid solution and the alkali solution, and the concentration of the acid solution and the alkali solution through the data acquisition mechanism, and conduct a full simulation study on the parameters affecting the initial membrane resistance, so as to determine the optimal parameters that can balance energy consumption and current efficiency under different seawater conditions.

[0029] This embodiment provides an experimental method. In this experimental method, the acid chamber volume, alkali chamber volume, salt chamber volume, voltage, acid concentration and alkali concentration can be adjusted as needed, and the optimal parameters of the acid solution, alkali solution, salt chamber volume, acid chamber volume and alkali chamber volume in different seawater are determined according to preset conditions to guide the electrodialysis treatment methods in different marine and island environments.

[0030] This embodiment provides a method for self-sustaining fresh water for islands. Since this method is based on optimal parameters for electrodialysis treatment, energy consumption and current efficiency are balanced during the electrodialysis treatment process, so that the maximum acid-base product concentration can be obtained with minimum energy consumption during the desalination process of seawater on the island, which can be used for cleaning reverse osmosis membranes. This not only effectively solves the problem of fresh water shortage in island areas, but also provides an economical and efficient cleaning agent, showing important application prospects and market potential. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0032] Figure 1 A schematic diagram of the structure of an experimental device provided in the first aspect of an embodiment of the present invention;

[0033] Figure 2 A schematic flow chart of the steps of an experimental method provided in the second aspect of an embodiment of the present invention;

[0034] Figure 3 Schematic diagram of the results of the BMED process with different preset voltages provided in Embodiments 1 to 5 of the present invention;

[0035] Figure 4 A schematic diagram of acid production energy consumption and current efficiency of the BMED process with different preset voltages provided in Embodiments 1 to 5 of the present invention;

[0036] Figure 5 Schematic diagram of the results of BMED processes with different acid and alkali concentrations provided in Examples 6 to 11 of the present invention;

[0037] Figure 6 A schematic diagram of the acid production energy consumption and current efficiency of the BMED process with different acid and alkali concentrations provided in Examples 6 to 11 of the present invention;

[0038] Figure 7Schematic diagram of the results of BMED processes with different volume ratios provided in Examples 11 to 15 of the present invention;

[0039] Figure 8 Schematic diagram of acid generation energy consumption and current efficiency of BMED processes with different volume ratios provided in Examples 11 to 15 of the present invention.

[0040] Reference numerals:

[0041] 1. Membrane group mechanism; 2. Liquid circulation mechanism; 20. Electrode container; 21. Salt container; 22. Acid container; 23. Alkali container; 3. Power supply mechanism. DETAILED DESCRIPTION

[0042] In order to make the purpose, features and advantages of the present invention more obvious and easy to understand, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the embodiments described below are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0043] Bipolar membrane electrodialysis (BMED) technology has received increasing attention in the field of wastewater treatment in recent years due to its high efficiency and environmental protection. The core principle of this technology is to use the electric field to make the cation and anion membranes selectively permeable, thereby realizing the separation and concentration of acid and base ions in the solution. Compared with traditional electrodialysis technology, bipolar membranes can not only separate and remove harmful components in wastewater, but also generate reusable acids and bases at the same time. This feature makes it have significant advantages in various applications such as electroplating wastewater, pharmaceutical waste liquid and industrial circulating water. In practical applications, factors affecting BMED efficiency or initial membrane resistance include current density, feed concentration and pH value.

[0044] Current density is one of the most critical operating parameters in BMED technology, which directly affects the migration speed of ions and the reaction efficiency of the membrane. When the current density is moderately increased, it can quickly promote the migration of anions and cations and accelerate the production of acids and bases. This acceleration effect is conducive to improving the productivity of the entire process and reducing unit energy consumption. However, too high current density will also bring some problems. First, the increase in current density may cause overheating of the electrode, resulting in local temperature increase, thereby aggravating the aging and damage of the membrane material. Secondly, too high current may cause polarization, affect the uniformity of the reaction, and ultimately affect the overall separation efficiency. Therefore, finding an ideal current density range that can both improve efficiency and maintain membrane stability is the key to implementing this technology.

[0045] The feed concentration affects the exchange and migration of ions between membranes. Appropriate ion concentration can improve conductivity and enhance the driving force of the electrolytic reaction. However, if the ion concentration in the feed is too low, the reaction rate may be slowed down and the generation of acids and bases may be insufficient. On the contrary, excessively high ion concentration may lead to mutual interference between ions, resulting in ion competition and reduced separation efficiency. In actual operation, detailed experiments are required to design the concentration of the feed solution in order to determine the optimal concentration range. For example, by adjusting the conditions of the feed solution, the current, ion exchange rate, etc. can be optimized while meeting the processing requirements, thereby improving the efficiency of the entire process.

[0046] The regulation of pH also has a significant impact on the efficiency of BMED. Different pH environments affect the electrical properties of the membrane and the binding characteristics of ions, resulting in different separation effects. For example, some membrane materials exhibit better conductivity under acidic conditions, while their ion conductivity is reduced under alkaline conditions. This phenomenon makes the optimization of pH an important factor that may affect the overall performance of BMED. During the application process, real-time monitoring and adjustment of the pH value in the system can not only enhance the separation effect, but also ensure the long life and efficient operation of the membrane. At the same time, the optimization of pH value also helps to reduce by-products in the reaction, reduce negative impacts on the environment, and further promote the sustainable development of the technology. Therefore, optimizing these parameters to ensure the best treatment effect and long life of the membrane is one of the current research focuses.

[0047] As can be seen from the above, in the research and application of bipolar membrane electrodialysis (BMED) technology, optimizing the above parameters to improve system efficiency is a complex and important task; these parameters not only directly affect the effect of the separation process, but also involve multiple considerations such as economic and environmental sustainability; therefore, in-depth exploration of these main influencing factors and their interactions is particularly critical.

[0048] The embodiments of the present invention provide an experimental device, an experimental method and a method for self-sustaining island freshwater, which aim to solve the technical problem in the prior art that it is impossible to simulate and study parameters such as pH value, volume ratio of chambers, and voltage to determine the optimal parameters for balancing energy consumption and current efficiency.

[0049] See also Figure 1 , the present invention provides an experimental device, comprising:

[0050] The membrane group structure 1 comprises an anode, a cathode and a plurality of membrane bodies, wherein a polar chamber, a salt chamber with a variable volume, an acid chamber with a variable volume and an alkali chamber with a variable volume are separated between the anode and the cathode by the plurality of membrane bodies;

[0051] A liquid circulation mechanism 2, for forming a circulation loop with the electrode chamber, a salt container with the salt chamber, an acid container with the acid chamber, and an alkali container with the alkali chamber;

[0052] A power supply mechanism 3, electrically connected to the anode and the cathode, and used to adjust the voltage between the anode and the cathode;

[0053] The data acquisition mechanism is used to collect the current of the experimental device, the electrolysis time, the volume of the acid solution and the alkaline solution, and the concentration of the acid solution and the alkaline solution.

[0054] During the working process of this embodiment, a sufficient amount of electrolyte solution is first added to the electrode container 20, a sufficient amount of acid solution is added to the acid container 22, a sufficient amount of alkaline solution is added to the alkaline container 23, and a sufficient amount of seawater is added to the salt container 21. Then, the electrolyte solution is circulated between the electrode chamber and the electrode container 20, the acid solution is circulated between the acid chamber and the acid container 22, the alkaline solution is circulated between the alkaline chamber and the alkaline container 23, and the seawater is circulated between the salt chamber and the salt container 21. The power supply mechanism 3 is turned on to perform electrodialysis treatment. The data acquisition mechanism collects the current, electrolysis time, volume of the acid solution and the alkaline solution, and concentration of the acid solution and the alkaline solution. The collected data is used to determine the optimal judgment index and production index, so that the user can determine the optimal parameters of balanced energy consumption and current efficiency corresponding to different seawater.

[0055] From the above working process, it can be seen that the volume of the acid chamber, the volume of the alkali chamber, the volume of the salt chamber, the preset voltage, the acid concentration and the alkali concentration can all be adjusted. The user can conduct a full simulation study on the parameters that affect the initial membrane resistance, so that in the face of different seawater environments, an optimal parameter that balances energy consumption and current efficiency can be found to guide subsequent electrodialysis treatment.

[0056] As an example, an achievable structure of a membrane group mechanism 1 is further provided, wherein the module mechanism includes a shell and a cathode and an anode arranged in the shell, two bipolar membranes, an anion exchange membrane and a cation exchange membrane are arranged between the cathode and the anode, an anion exchange membrane and a cation exchange membrane are arranged in sequence between the two bipolar membranes, forming a three-compartment structure including a salt chamber, an acid chamber and an alkali chamber, a polar chamber is formed between the cathode and the bipolar membrane, and a polar chamber is formed between the anode and the bipolar membrane.

[0057] In one embodiment, the volume of the salt chamber, the volume of the acid chamber and the volume of the alkali chamber will change spontaneously, that is, the volumes of the salt chamber, the acid chamber and the alkali chamber will change spontaneously during the electrodialysis treatment. For example, if the salt concentration in the salt chamber is higher than that in the adjacent chamber, a small amount of water molecules will pass through the ion exchange membrane into the salt chamber, resulting in a slight increase in the volume of the salt chamber; and the volume of the adjacent chamber will decrease slightly accordingly, thereby achieving volume change regulation. In specific implementation, the user can determine the optimal parameters by recording the volume change and the parameters brought about by the volume change.

[0058] Based on the above embodiments, the volume of the salt chamber, the volume of the acid chamber and the volume of the alkali chamber can be actively adjusted by the user. The specific volume adjustment method is to control the inlet flow rate of the salt chamber to a preset value, continuously pump seawater into the salt chamber, and simultaneously realize the generation or discharge of the acid chamber and the alkali chamber. The salt chamber is continuously filled with seawater, thereby increasing its volume, and the generated acid and alkali are discharged from the corresponding chamber, forming an experimental device with a volume stable at a preset value; of course, the changes in the other chambers can also refer to this example, and will not be described in detail here.

[0059] In one embodiment, the membrane is separated from the electrode plate by a partition to ensure a stable distance between the membrane and the partition; different ion exchange membranes are isolated by a polyvinyl fluoride mesh, and the gap between each membrane is 0.7 mm; in addition, the membrane and the partition form the direction of liquid flow, so that it flows in the originally specified direction; the effective membrane area of ​​each membrane is 297 cm², and the electrode used is a specially made modified titanium plate with an area of ​​162 cm², and the electrode chamber is connected to the electrode.

[0060] As an example, Figure 1 As shown, an achievable structure of a liquid circulation mechanism 2 is further provided, and the liquid circulation mechanism 2 includes an electrode container 20, a salt container 21, an acid container 22, an alkali container 23 and a plurality of pump bodies; the electrode container 20 is connected to the water inlet and outlet of the electrode chamber through a pipeline, and a pump body is provided between the electrode container 20 and the electrode chamber; the salt container 21 is connected to the water inlet and outlet of the salt chamber through a pipeline, and a pump body is provided between the salt container 21 and the salt chamber; the acid container 22 is connected to the water inlet and outlet of the acid chamber through a pipeline, and a pump body is provided between the acid container 22 and the acid chamber; the alkali container 23 is connected to the water inlet and outlet of the alkali chamber through a pipeline, and a pump body is provided between the alkali container 23 and the alkali chamber, so as to form a plurality of independent circulation loops.

[0061] As an example, an achievable structure of a data acquisition mechanism is further provided, wherein the data acquisition mechanism includes a current sensor, a time sensor, an acid-base solution volume sensor, and an acid-base solution concentration sensor, wherein the current sensor may be a current transformer, a Hall current sensor, a Rogowski coil current sensor, etc.; the time sensor may be an electronic stopwatch, a timer, etc.; the acid-base solution volume sensor may be a flow meter; the acid-base solution concentration sensor may be an acid-base concentration meter, an optical sensor, etc. In specific implementation, the collected data is used to calculate optimal judgment indicators such as current efficiency and energy consumption, as well as production indicators such as acid-base products and desalination rate.

[0062] See also Figure 2 The present invention provides an experimental method, which uses the above-mentioned experimental device and includes the following steps:

[0063] S1, electrolyte solution is introduced into the electrode chamber, seawater is introduced into the salt chamber, acid solution and alkaline solution are introduced into the acid chamber and alkaline chamber respectively;

[0064] S2, the power supply mechanism applies a preset voltage to the membrane group mechanism, and performs electrodialysis to obtain a product, wherein the data collection mechanism collects electrodialysis process data;

[0065] S3, changing the parameters of the preset voltage, the parameters of the acid solution, the parameters of the alkaline solution, the volume of the salt chamber, the volume of the acid chamber, and the volume of the alkaline chamber within the preset range, and repeating S1 to S3 until a preset number of parameters within the preset range are executed;

[0066] S4, based on the electrodialysis process data, determining optimal parameters of a preset voltage, an acid solution, an alkaline solution, a salt chamber volume, an acid chamber volume, and an alkaline chamber volume according to preset conditions.

[0067] In this embodiment, the concentrations of the acid solution and the alkaline solution can be determined and added by the user, that is, the concentrations of the acid solution and the alkaline solution are adjustable and replaceable, and the volume of the salt chamber, the volume of the acid chamber and the volume of the alkaline chamber are due to the fact that they can change spontaneously and regularly to form different volumes or the user changes their structure to form different volumes, that is, the volume of the salt chamber, the volume of the acid chamber and the volume of the alkaline chamber are adjustable. Therefore, when the user processes different seawater, he can adjust different preset voltages, acid chamber volumes, alkaline chamber volumes, salt chamber volumes, voltages, acid concentrations and alkaline concentrations through multiple tests to obtain the optimal parameters that meet the balance between energy consumption and current efficiency under different seawater conditions.

[0068] As an example, an achievable method in step S1 is further provided, and step S1 specifically comprises: introducing an electrolyte solution into the electrode chamber, wherein the electrolyte solution is a sulfate solution, and the concentration of the sulfate solution is 0.02-0.07 mol / L; introducing seawater into the salt chamber; introducing an acid solution into the acid chamber, wherein the preset range of the concentration of the acid solution is 0-0.25 mol / L; introducing an alkali solution into the alkali chamber, wherein the preset range of the concentration of the alkali solution is 0-0.25 mol / L; the preset range of the volume ratio of the salt chamber to the acid chamber is 1:1-4:1; the preset range of the volume ratio of the salt chamber to the alkali chamber is 1:1-4:1, and the solution flow rate of the electrode chamber, salt chamber, acid chamber and alkali chamber is 20-40 L / h. These parameters and their ranges can be used alone or in combination. The parameters and their ranges in step S1 are selected from parameters and ranges obtained from preliminary experiments that are suitable for marine environments, have low energy consumption and relatively good current efficiency effects.

[0069] As an example, an implementable method in step S2 is further provided. Step S2 is specifically as follows: the power supply mechanism applies a preset voltage of 10-18V within a preset range to the membrane group mechanism, and performs electrodialysis to obtain a product, wherein the data acquisition mechanism collects data of the electrodialysis process. This voltage parameter and its range can be used alone or in combination with other parameters. The parameters and their ranges in step S2 are parameters and ranges selected from preliminary experiments that are suitable for the marine environment, have low energy consumption and relatively good current efficiency effects.

[0070] As an example, in order to improve the accuracy of the optimal parameters, the following steps are also included between step S1 and step S2: the power supply mechanism applies a bubble removal voltage to the membrane group mechanism, so that the solution in the experimental device circulates for a preset time to remove the bubbles in the experimental device, wherein the preset time is 30 minutes. After specific implementation, the original bubbles in the device can be removed and the membrane stack resistance can be reduced.

[0071] Based on the above embodiments, in step S3, the preset voltage can be changed between 10-18V, the concentration of the acid solution can be changed between 0-0.25mol / L, the concentration of the alkaline solution can be changed between 0-0.25mol / L, the volume ratio of the salt chamber to the acid chamber can be changed between 1:1-4:1, and the volume ratio of the salt chamber to the alkaline chamber can be changed between 1:1-4:1, so as to carry out experiments of different types and parameters.

[0072] As an example, an implementable method in step S4 is further provided, and step S4 is specifically: based on the electrodialysis process data, taking 1kg of acid production as the amount for calculation, the optimal parameters of the preset voltage are determined based on the maximum current efficiency, the optimal parameters of the acid solution and the optimal parameters of the alkaline solution are determined based on the maximum current efficiency, and the optimal parameters of the salt chamber volume, the optimal parameters of the acid chamber volume and the optimal parameters of the alkaline chamber volume are determined based on the conditions of large current efficiency, high acid and alkali concentrations and low energy consumption.

[0073] In one embodiment, the current efficiency is calculated as follows:

[0074]

[0075] In the above formula, CE is the current efficiency (unit %), Ct is the concentration of acid or base in the acid or base chamber at time t (unit mol / L), Vt is the volume of acid or base at time t (unit L), C0 is the concentration of acid or base in the acid or base chamber at time 0 (unit mol / L), V0 is the volume of acid or base at time 0 (unit L), t is the experimental running time (unit min), z is the ion valence, F is the Faraday constant (96485 C / mol); I is the current at time t (unit A); N is the number of membrane stack units.

[0076] In one embodiment, the energy consumption is calculated as follows:

[0077]

[0078] In the above formula, EC is the acid energy consumption (unit kWh / kg), U is the membrane stack voltage (unit V), I is the current at time t (unit A), Ct is the concentration of the acid or base in the acid or base chamber at time t (unit mol / L), Vt is the volume of the acid or base at time t (unit L), C0 is the concentration of the acid or base in the acid or base chamber at time 0 (unit mol / L), V0 is the volume of the acid or base at time 0 (unit L), t is the experimental running time (unit min), and M is the molar mass of the acid (unit g / mol).

[0079] See also Figures 3 to 8 The present invention provides a method for self-sustaining island freshwater, which applies the optimal parameters obtained by the above-mentioned experimental method, and uses the optimal parameters to perform electrodialysis treatment to obtain products. By optimizing the optimal parameters of bipolar membrane electrodialysis, the maximum acid-base product concentration (acid-base cleaning agent) can be obtained with the minimum energy consumption during the island seawater desalination process, which is used for cleaning the reverse osmosis membrane.

[0080] As an example, a method for self-sustaining freshwater on an island is further provided, comprising the following steps:

[0081] A1, 0.02 mol / L sodium sulfate electrolyte solution is introduced into the electrode chamber, island seawater is introduced into the salt chamber, 0.05 mol / L hydrochloric acid solution and 0.05 mol / L sodium hydroxide solution are introduced into the acid chamber and the alkali chamber respectively, wherein the volume ratio of the salt chamber to the acid chamber is 2:1, and the volume ratio of the salt chamber to the alkali chamber is 2:1;

[0082] A2, the power supply mechanism applies a preset voltage of 16V to the membrane group mechanism, and performs electrodialysis to obtain a product.

[0083] During specific implementation, the acid-base cleaning agent generated has significant economy and practicality, and can meet the diverse needs of different industrial fields on the island; this cleaning agent (product) not only performs well in treatment effect, but also has obvious advantages in cost control, thereby effectively reducing the overall cost of the cleaning process; in addition, the use of this cleaning agent can significantly improve the overall performance of the reverse osmosis system, improve its efficiency and stability, and thus extend the service life of the equipment; by adopting the cleaning agent produced by double-membrane electrodialysis, enterprises can achieve sustainable development goals while maintaining high cleaning effects and further promote technological innovation and application upgrades in the field of industrial cleaning.

[0084] The present invention is particularly suitable for remote areas such as islands, which usually face the challenges of scarce resources, inconvenient transportation and backward infrastructure. With its excellent adaptability and flexibility, the invention can operate efficiently in complex and changeable environments. Whether it is stability under extreme weather conditions or lack of energy and materials, it can still maintain excellent performance. This design not only meets the special needs of remote areas, but also provides practical solutions for local sustainable development. At the same time, it brings new opportunities for improving the quality of life and economic development in these areas, and further promotes the widespread application of technology.

[0085] Embodiments 1 to 5 investigate the effects of different preset voltages on BMED process performance. Figure 3 and Figure 4 shown.

[0086] Embodiment 1

[0087] The preset voltage was set to 10 V, the concentrations of the hydrochloric acid solution and the sodium hydroxide solution were both 0.05 mol / L, the volume ratio of the salt chamber to the acid chamber was 1:1, the volume ratio of the salt chamber to the alkali chamber was 1:1, the electrolyte solution was 0.02 mol / L sodium sulfate solution, and the island native seawater was pumped into the salt chamber. The speed of all circulation loops was 20 L / h, and the above parameters were used for BMED process treatment.

[0088] Embodiment 2

[0089] The preset voltage was set to 12 V, the concentrations of hydrochloric acid solution and sodium hydroxide solution were both 0.05 mol / L, the volume ratio of the salt chamber to the acid chamber was 1:1, the volume ratio of the salt chamber to the alkali chamber was 1:1, 0.02 mol / L sodium sulfate solution, and the island native seawater was pumped into the salt chamber. The speed of all circulation loops was 20 L / h, and the above parameters were used for BMED process treatment.

[0090] Embodiment 3

[0091] The preset voltage was set to 14 V, the concentrations of hydrochloric acid solution and sodium hydroxide solution were both 0.05 mol / L, the volume ratio of the salt chamber to the acid chamber was 1:1, the volume ratio of the salt chamber to the alkali chamber was 1:1, 0.02 mol / L sodium sulfate solution, and the island native seawater was pumped into the salt chamber. The speed of all circulation loops was 20 L / h, and the above parameters were used for BMED process treatment.

[0092] Embodiment 4

[0093] The preset voltage was set to 16 V, the concentrations of hydrochloric acid solution and sodium hydroxide solution were both 0.05 mol / L, the volume ratio of the salt chamber to the acid chamber was 1:1, the volume ratio of the salt chamber to the alkali chamber was 1:1, 0.02 mol / L sodium sulfate solution, and the island native seawater was pumped into the salt chamber. The speed of all circulation loops was 20 L / h, and the above parameters were used for BMED process treatment.

[0094] Embodiment 5

[0095] The preset voltage was set to 18 V, the concentrations of hydrochloric acid solution and sodium hydroxide solution were both 0.05 mol / L, the volume ratio of the salt chamber to the acid chamber was 1:1, the volume ratio of the salt chamber to the alkali chamber was 1:1, 0.02 mol / L sodium sulfate solution, and the island native seawater was pumped into the salt chamber. The speed of all circulation loops was 20 L / h, and the above parameters were used for BMED process treatment.

[0096] Figure 3 Schematic diagram of the results of the BMED process with different preset voltages provided in Embodiments 1 to 5 of the present invention.

[0097] Figure (3)a shows the current distribution of the membrane stack under different voltages. The acid and base compartments of the BMED membrane stack are added with high-conductivity hydrochloric acid and sodium hydroxide, which makes the impedance of the membrane-solution interface low. According to Ohm's law, the impedance of the BMED membrane stack is inversely proportional to the current, so the initial current value is high. As the charged ions continue to migrate to the acid chamber and the base chamber through the ion channels of the anion exchange membrane and the cation exchange membrane, the migration resistance gradually becomes the main limiting factor, resulting in a significant decrease in the kinetic activity of the charged ion conduction current. When the load ions in the electrolyte solution are not enough to maintain current conduction, the current will reach an equilibrium state under different voltage conditions.

[0098] As can be seen from Figure (3) b, the higher the voltage, the stronger the driving force for the migration of the charged ions, and thus the faster the desalination rate. This is because a higher potential gradient can effectively enhance the electrical migration ability of the charged ions, enabling them to achieve the maximum efficiency of salt conversion in a shorter time.

[0099] Figure (3) c and Figure (3) d show that increasing the voltage helps to increase the rate of acid and base generation; and higher voltage can promote the migration of anions and cations to their respective compartments, thereby synthesizing acids and bases; this is because high voltage enhances the ability of ions to migrate across the membrane and also increases the hydrolysis of BPM to and rate, thereby effectively increasing the extreme concentrations of the product acid (0.35mol / L) and base (0.31mol / L).

[0100] Figure 4 Schematic diagram of acid generation energy consumption and current efficiency of BMED processes with different preset voltages provided in Embodiments 1 to 5 of the present invention.

[0101] Figure 4 The electrochemical performance of BMED at different voltages was demonstrated; the results showed that increasing the voltage helped to improve the ion mass transfer rate; however, continuously increasing the voltage would lead to a decrease in the selectivity of the ion exchange membrane, which exacerbated the rapid hydrolysis of BPM. and Migration competition and leakage between ions significantly reduce The mass transfer efficiency of ions; therefore, when the voltage increases from 10V to 16V, the current efficiency increases from 16.60% to 39.39%; however, when the voltage is further increased to 18V, the current efficiency decreases slightly to 39.08%; the Joule heat generated to promote the transport of charged ions and overcome the migration resistance determines the degree of energy consumption of the membrane stack, and the concentration polarization phenomenon formed by the increase in voltage will also increase the degree of restriction on ion migration, which causes the membrane stack to consume more energy to counteract the migration resistance of the mass transfer process; therefore, the energy consumption at 18V increases by 0.5, 0.47 and 0.45kW·h / kg compared with 12V, 14V and 16V, respectively.

[0102] It can be seen from the results of Examples 1 to 5 that increasing the voltage can certainly shorten the entire experimental time, but it will increase energy consumption, and the shortened membrane life caused by high voltage are all issues that need to be considered. Therefore, after comprehensive consideration, the 16V voltage when the current efficiency is maximum is used as the optimal preset voltage parameter.

[0103] Examples 6 to 11 investigated the effects of different acid and alkali concentrations on the BMED process performance. Figure 5 and Figure 6 shown.

[0104] Embodiment 6

[0105] The preset voltage was set to 16 V, the concentrations of the hydrochloric acid solution and the sodium hydroxide solution were both 0.00 mol / L, the volume ratio of the salt chamber to the acid chamber was 1:1, the volume ratio of the salt chamber to the alkali chamber was 1:1, the electrolyte solution was 0.02 mol / L sodium sulfate solution, and the island native seawater was pumped into the salt chamber. The speed of all circulation loops was 20 L / h, and the above parameters were used for BMED process treatment.

[0106] Embodiment 7

[0107] The preset voltage was set to 16 V, the concentrations of the hydrochloric acid solution and the sodium hydroxide solution were both 0.05 mol / L, the volume ratio of the salt chamber to the acid chamber was 1:1, the volume ratio of the salt chamber to the alkali chamber was 1:1, the electrolyte solution was 0.02 mol / L sodium sulfate solution, and the island native seawater was pumped into the salt chamber. The speed of all circulation loops was 20 L / h, and the above parameters were used for BMED process treatment.

[0108] Embodiment 8

[0109] The preset voltage was set to 16 V, the concentrations of the hydrochloric acid solution and the sodium hydroxide solution were both 0.10 mol / L, the volume ratio of the salt chamber to the acid chamber was 1:1, the volume ratio of the salt chamber to the alkali chamber was 1:1, the electrolyte solution was 0.02 mol / L sodium sulfate solution, and the island native seawater was pumped into the salt chamber. The speed of all circulation loops was 20 L / h, and the above parameters were used for BMED process treatment.

[0110] Embodiment 9

[0111] The preset voltage was set to 16 V, the concentrations of the hydrochloric acid solution and the sodium hydroxide solution were both 0.15 mol / L, the volume ratio of the salt chamber to the acid chamber was 1:1, the volume ratio of the salt chamber to the alkali chamber was 1:1, the electrolyte solution was 0.02 mol / L sodium sulfate solution, and the island native seawater was pumped into the salt chamber. The speed of all circulation loops was 20 L / h, and the above parameters were used for BMED process treatment.

[0112] Embodiment 10

[0113] The preset voltage was set to 16 V, the concentrations of the hydrochloric acid solution and the sodium hydroxide solution were both 0.20 mol / L, the volume ratio of the salt chamber to the acid chamber was 1:1, the volume ratio of the salt chamber to the alkali chamber was 1:1, the electrolyte solution was 0.02 mol / L sodium sulfate solution, and the island native seawater was pumped into the salt chamber. The speed of all circulation loops was 20 L / h, and the above parameters were used for BMED process treatment.

[0114] Embodiment 11

[0115] The preset voltage was set to 16 V, the concentrations of the hydrochloric acid solution and the sodium hydroxide solution were both 0.25 mol / L, the volume ratio of the salt chamber to the acid chamber was 1:1, the volume ratio of the salt chamber to the alkali chamber was 1:1, the electrolyte solution was 0.02 mol / L sodium sulfate solution, and the island native seawater was pumped into the salt chamber. The speed of all circulation loops was 20 L / h, and the above parameters were used for BMED process treatment.

[0116] Figure 5 Schematic diagram of the results of the BMED process with different acid and alkali concentrations provided in Examples 6 to 11 of the present invention.

[0117] Figure (5) a shows that the effect of the initial acid-base concentration on the membrane stack current is mainly in the initial stage. A higher initial concentration can give the charged ions a high active site, greatly weakening the inertia of ion migration. After 70 minutes, the current change is generally consistent with other initial concentrations.

[0118] As shown in Figure (5) c and Figure (5) d, the effect of initial acid and base concentrations on their yields; when the initial concentration was 0.05 mol / L, the yields of acid (0.35 mol / L) and base (0.30 mol / L) were obtained, and a desalination effect of 74.80% was achieved ( Figure 3 , c); when the initial acid-base concentration increased from 0.05mol / L to 0.25mol / L, the acid-base concentration also increased to the yield of acid (0.45mol / L) and base (0.41mol / L), but the desalination effect decreased from 74.80% to 62.45%; this finding may be caused by the reverse diffusion of ions, which aggravates the leakage, and the high initial concentration causes BMP (bipolar membrane) to be unable to replenish sufficient water molecules due to high osmotic pressure, resulting in an incomplete hydrolysis mechanism of BMP and a low kinetic conversion rate of BMED.

[0119] like Figure 6 As shown in the figure, the effect of initial acid-base concentration on the electrochemical performance of BMED. When the initial acid-base concentration increases from 0 mol / L to 0.25 mol / L, the acid energy consumption increases from 1.81 kW·h / kg to 3.49 kW·h / kg, and the electrochemical conversion efficiency decreases from 38.99% to 20.18%. This is because the contribution of voltage to the driving force of the charged ions varies with the migration resistance. When the initial concentration increases, the conductivity of the solution increases, and the barrier for ions to overcome the repulsive force of adjacent compartments decreases. However, with the formation of concentration differences between adjacent salt chambers, the kinetic activity of the diffusion and electromigration of charged ions decreases, and the energy consumption of BMED to directly overcome the ion migration resistance increases. Especially in the case of high initial concentration, the product conversion efficiency will be significantly reduced.

[0120] It can be seen from the results of Examples 6 to 11 that in order to achieve a higher electrochemical conversion rate of ions in the electrolyte solution, the initial acid and alkali concentration added should not be too high. When the initial acid and alkali concentration added is 0.05 mol / L, the lowest energy consumption of 1.80 kW·h / kg and the highest product conversion rate of 39.39% are achieved. Therefore, the optimal parameter of acid and alkali concentration is 0.05 mol / L.

[0121] Examples 11 to 15 investigated the effects of different (salt chamber: acid-base chamber) volume ratio concentrations on the BMED process performance. The results are as follows: Figure 7 and Figure 8 shown.

[0122] Embodiment 12

[0123] The preset voltage was set to 16 V, the concentrations of the hydrochloric acid solution and the sodium hydroxide solution were both 0.05 mol / L, the volume ratio of the salt chamber to the acid chamber was 1:1, the volume ratio of the salt chamber to the alkali chamber was 1:1, the electrolyte solution was 0.02 mol / L sodium sulfate solution, and the island native seawater was pumped into the salt chamber. The speed of all circulation loops was 20 L / h, and the above parameters were used for BMED process treatment.

[0124] Embodiment 13

[0125] The preset voltage was set to 16 V, the concentrations of the hydrochloric acid solution and the sodium hydroxide solution were both 0.05 mol / L, the volume ratio of the salt chamber to the acid chamber was 2:1, the volume ratio of the salt chamber to the alkali chamber was 2:1, the electrolyte solution was 0.02 mol / L sodium sulfate solution, and the island native seawater was pumped into the salt chamber. The speed of all circulation loops was 20 L / h, and the above parameters were used for BMED process treatment.

[0126] Embodiment 14

[0127] The preset voltage was set to 16 V, the concentrations of the hydrochloric acid solution and the sodium hydroxide solution were both 0.05 mol / L, the volume ratio of the salt chamber to the acid chamber was 3:1, the volume ratio of the salt chamber to the alkali chamber was 3:1, the electrolyte solution was 0.02 mol / L sodium sulfate solution, and the island native seawater was pumped into the salt chamber. The speed of all circulation loops was 20 L / h, and the above parameters were used for BMED process treatment.

[0128] Embodiment 15

[0129] The preset voltage was set to 16V, the concentrations of hydrochloric acid solution and sodium hydroxide solution were both 0.05mol / L, the volume ratio of the salt chamber to the acid chamber was 4:1, the volume ratio of the salt chamber to the alkali chamber was 4:1, the electrolyte solution was 0.02mol / L sodium sulfate solution, and the island native seawater was pumped into the salt chamber. The speed of all circulation loops was 20L / h, and the above parameters were used for BMED process treatment.

[0130] Figure 7 Schematic diagram of the results of BMED processes with different volume ratios provided in Embodiments 11 to 15 of the present invention.

[0131] Figure (7) a shows that as the volume ratio of the salt chamber to the acid-base chamber increases, the limiting current value increases, from the maximum current of 1.86A at 1:1 to 2.08A at 4:1. The increase in the volume ratio of the salt chamber to the product chamber can provide more charge carriers for the electrolyte solution, which is beneficial to the reduction of the membrane stack resistance. However, the increase in the electrolyte solution will prolong the time it takes for ions to leave the salt chamber, such as Figure 7 (b) The desalination rates at 3:1 (54.07%) and 4:1 (46.83%) were lower; the main reason was that the inherent exchange groups on the surface of AEM (anionic membrane) and CEM (cationic membrane) limited the number of charged ions that could permeate through the membrane, so the expected desalination target required more time to transfer a large number of ions.

[0132] Figure (7) (c) and Figure (7) (d) show that the increase in volume ratio can achieve the synthesis of high acid and base concentrations. During the 100-min desalination process, the product concentrations at volume ratios of 3:1 and 4:1 were significantly lower than those at high volume ratios (1:1 and 2:1). Thanks to the excellent ion channels constructed at the membrane-solution interface by the high volume ratio, the final product acid concentration increased from 0.35 mol / L (1:1) to 0.65 mol / L (4:1), and the product base also increased by 0.28 mol / L on the original basis.

[0133] The electric driving force obtained by the ions in the constant pressure mode is the same, so the improvement of the desalination rate and mass transfer rate depends on the strong driving force of the concentration gradient. However, the migration of overcharged ions is inevitably accompanied by high energy output, such as Figure 8 As shown in the figure, when the volume ratio is 4:1, the energy consumption reaches 3.49kW·h / kg. When the concentration of the synthesized product is high, the advantage of the concentration gradient is significantly reduced, which inhibits the transfer rate and kinetic activity of most ions and passivates the charge transfer of the charged ions and the product synthesis rate. Therefore, this transformation prolongs the time for ions to pass through the membrane, resulting in a decrease in the electrochemical conversion efficiency of ions from 39.39% (1:1) to 20.20% (4:1).

[0134] From the results of Example 12 to Example 15, it can be seen that the experimental selection of a volume ratio of 2:1 can obtain higher concentrations of acid (0.48 mol / L) and base (0.41 mol / L), and has lower energy consumption (2.14 kW·h / kg) and higher current efficiency (32.97%).

[0135] In summary, the optimal parameters of the BMED process are: preset voltage (16V), electrolyte concentration (0.02mol / LNaSO4), initial acid and alkali concentration (0.05mol / L), the volume ratio of the salt chamber to the acid and alkali chamber is (2:1), and a higher concentration of product acid (0.48mol / L) and product alkali (0.41mol / L) is obtained. The process energy consumption is 2.14kW·h / kg, and the electrochemical conversion efficiency is 32.97%; the concentration range of the acid and alkali solution required for the cleaning process of the island reverse osmosis desalination membrane is roughly 0.5% to 1%. This means that in actual operation, it is necessary to ensure that the acid or alkali concentration of the cleaning solution falls within this range to effectively remove pollutants and impurities accumulated on the membrane surface. At the same time, by optimizing the technical parameters of bipolar membrane electrodialysis and using seawater as raw material, a maximum concentration of 0.48mol / L (about 1.75%) hydrochloric acid and 0.41mol / L (about 1.64%) sodium hydroxide solution can be produced.

[0136] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that the technical solutions described in the aforementioned embodiments may still be modified, or some of the technical features may be replaced by equivalents. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

[0137] The terms "first", "second", "third", "fourth", etc. (if any) in the specification of the present application and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the data used in this way can be interchangeable where appropriate, so that the embodiments of the present application described herein can be implemented in an order other than those illustrated or described herein, for example. In addition, the terms "including" and "having" and any of their variations are intended to cover non-exclusive inclusions, for example, a process, method, system, product or device that includes a series of steps or units is not necessarily limited to those steps or units that are clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0138] Finally, it should be noted that, in this article, relational terms such as first and second, etc. are merely used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations.

Claims

1. An experimental device, characterized in that: include: A membrane group structure, comprising an anode, a cathode and a plurality of membrane bodies, wherein a polar chamber, a salt chamber with a variable volume, an acid chamber with a variable volume and an alkali chamber with a variable volume are separated between the anode and the cathode by the plurality of membrane bodies; A liquid circulation mechanism, comprising a pole container for forming a circulation loop with the pole chamber, a salt container for forming a circulation loop with the salt chamber, an acid container for forming a circulation loop with the acid chamber, and an alkali container for forming a circulation loop with the alkali chamber; A power supply mechanism, electrically connected to the anode and the cathode, and used to adjust the voltage between the anode and the cathode; The data collection mechanism is used to collect the current of the experimental device, the electrolysis time, the volume of the acid solution and the alkaline solution, and the concentration of the acid solution and the alkaline solution.

2. The experimental device according to claim 1, characterized in that: The volume of the salt chamber, the volume of the acid chamber, and the volume of the base chamber may change spontaneously.

3. An experimental method, characterized in that: The experimental device according to any one of claims 1 or 2 is used; The following steps are involved: S1, introducing an electrolyte solution into the electrode chamber, introducing seawater into the salt chamber, and introducing an acid solution and an alkaline solution into the acid chamber and the alkaline chamber, respectively; S2, the power supply mechanism applies a preset voltage to the membrane group mechanism and performs electrodialysis to obtain a product; wherein the data collection mechanism collects electrodialysis process data; S3, changing the parameters of the preset voltage, the parameters of the acid solution, the parameters of the alkaline solution, the volume of the salt chamber, the volume of the acid chamber, and the volume of the alkaline chamber within a preset range, and repeating S1 to S3 until a preset number of parameters within the preset range are executed; S4, based on the electrodialysis process data, determining optimal parameters of a preset voltage, an acid solution, an alkaline solution, a salt chamber volume, an acid chamber volume, and an alkaline chamber volume according to preset conditions.

4. The experimental method according to claim 3, characterized in that The preset range of the concentration of the acid solution introduced into the acid chamber is 0-0.25 mol / L; the preset range of the concentration of the alkali solution introduced into the alkali chamber is 0-0.25 mol / L.

5. The experimental method according to claim 3, characterized in that: The preset range of the volume ratio of the salt chamber to the acid chamber is 1:1-4:1; the preset range of the volume ratio of the salt chamber to the alkali chamber is 1:1-4:

1.

6. The experimental method according to claim 3, characterized in that: The preset range of the preset voltage applied by the power supply mechanism to the membrane group mechanism is 10-18V.

7. The experimental method according to claim 3, characterized in that: The solution flow rate of the electrode chamber, the salt chamber, the acid chamber and the alkali chamber is 20-40 L / h.

8. The experimental method according to claim 3, characterized in that: Between step S1 and step S2, the following steps are also included: The power supply mechanism applies a bubble removal voltage to the membrane group mechanism, so that the solution in the experimental device circulates for a preset time to remove bubbles in the experimental device.

9. A method for self-sustaining fresh water on an island, characterized in that: The optimal parameters obtained by the experimental method described in any one of claims 3 to 8 are applied, and electrodialysis treatment is carried out based on the optimal parameters to obtain a product.

10. The method according to claim 9, characterized in that The seawater is island seawater, the preset voltage is 16V, the concentration of the acid solution passed into the acid chamber is 0.05mol / L, the concentration of the acid solution passed into the alkali chamber is 0.05mol / L, the volume ratio of the salt chamber to the acid chamber is 2:1, the volume ratio of the salt chamber to the alkali chamber is 2:1, and the electrolyte solution is 0.02mol / L sodium sulfate.

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