CN108114599A - It is a kind of based on salt error the electrodialysis reversal of production soda acid to be driven to couple bipolar membranous system and its production method - Google Patents

Abstract

The present invention provides a reverse electrodialysis coupling bipolar membrane system and its production method based on the ability of salt difference to drive the production of acid and alkali. In the electrodialysis chamber, the potential energy difference generated by it can drive the bipolar membrane to dissociate water to produce protons and hydroxide ions, which can generate acid and alkali in the chambers on both sides of the bipolar membrane. The system of the present invention can efficiently use the potential difference generated by ion migration to directly produce acid and alkali, does not require energy storage and conversion systems, reduces process energy loss, and can achieve production capacity while producing acid and alkali by adjusting operating parameters, and The process is simple, no additional energy is needed (except for pumping fluid), no pollution, and the efficiency of acid and alkali production is high.

Description

A Reverse Electrodialysis Coupled Bipolar Membrane System Based on Salt Difference Energy Driven Production of Acid and Base and its production method

technical field

The invention belongs to the technical field of acid and alkali preparation and sustainable energy, and specifically relates to a new method for preparing acid and alkali by using the salinity difference energy as a direct driving force to drive a bipolar membrane through reverse electrodialysis to dissociate water.

Background technique

Bipolar membrane is a new type of ion exchange composite membrane, which is usually composed of cation exchange layer, interface layer and anion exchange layer. Under the action of a DC electric field, the bipolar membrane can dissociate water, and protons and hydroxide ions are obtained on both sides of the membrane. Utilizing the characteristics of the bipolar membrane, combining it with other ion exchange membranes can convert the salt in the aqueous solution into the corresponding acid and alkali without introducing new components, thereby reducing the pollution to the environment and reducing the process time. cost. Therefore, bipolar membrane technology is widely used in processes such as brine desalination, ultrapure water preparation, water pollution control, and waste water recycling.

Reverse electrodialysis is an effective technology to convert the salt difference energy stored in brine into energy. Generally speaking, reverse electrodialysis is composed of anion and cation exchange membranes that are repeatedly stacked alternately, and the adjacent two membranes alternate Brine and river water are fed in to form concentrated solution chambers and dilute solution chambers arranged in sequence. When the anode and cathode at both ends are connected to the load and form a complete circuit, driven by the concentration difference, the anions and cations in the concentrated solution chamber pass through the anion and cation exchange membranes respectively by using the selective permeability of the ion exchange membrane. , and migrate to the dilute solution chamber to form an internal current for directional ion migration, and then through the electrochemical reaction of the cathode and anode, the internal current for ion migration can be converted into an external circuit current for electron migration to supply power to the load. As a new type of renewable energy technology, it also faces the problem of stable output like other renewable energy sources. The traditional reverse electrodialysis technology is affected by the climate environment, seasons and geographical location, and the electricity generated by it cannot be directly integrated into the For power grid applications, further conversion technologies need to be introduced to store salt production in the form of electrical energy or other energy. For example, literature [1] reported a combination of liquid flow batteries and reverse electrodialysis technology to convert salt difference energy into electrical energy. And storage technology, literature [2] reported a technology that connects reverse electrodialysis and alkaline electrolyzer, and converts salt difference energy into hydrogen energy to realize energy storage; patent CN 201710483766.3 reported a technology using Reverse electrodialysis technology is a technology that directly converts salt production into hydrogen energy by optimizing the electrolyte.

The invention assembles a bipolar membrane in a reverse electrodialysis membrane stack, and drives the bipolar membrane to undergo water dissociation under the action of the electric potential generated by the salt difference energy, and converts the salt in the brine into by-products of acid and alkali. This process directly converts the salt difference energy to produce acid-base, which can reduce the energy loss in the process. At the same time, by adjusting the operating parameters, it can realize the production of acid-base while increasing production capacity. The process is simple, no additional energy is needed, clean and pollution-free, and acid production is possible. Alkaline efficiency is high.

references:

[1] X. Zhu, T. Kim, M. Rahimi, et al. Integrating Reverse-Electrodialysis Stacks with Flow Batteries for Improved Energy Recovery from Salinity Gradients and Energy Storage. ChemSusChem, 2017, 10: 797-803.

[2]R.A.Tufa,E.Rugiero,D.Chanda,et al.Salinity gradient power-reverse electrodialysis and alkaline polymer electrolyte water electrolysis for hydrogen production.Journal of Membrane Science,2016,514:155-164.

Contents of the invention

In view of this, the technical problem to be solved by the present invention is to provide a reverse electrodialysis coupled bipolar membrane system and its production method that can drive the production of acid and base based on salinity difference.

The present invention is based on a sustainable clean energy source-salt difference energy, uses reverse electrodialysis to couple bipolar membrane membrane stacks, and the reverse electrodialysis part in the membrane stack converts the chemical potential energy of salt solutions with different concentrations on both sides of the membrane, and Directly acting on the bipolar membrane part of the membrane stack, the bipolar membrane undergoes water dissociation to generate protons and hydroxide ions, and then combines reverse electrodialysis to couple the ionic fluid flow in the bipolar membrane stack to form acids and bases. Therefore, the use of reverse electrodialysis described in the present invention as a means, combined with the bipolar membrane water dissociation system, and the bipolar membrane reverse electrodialysis method that can directly prepare acid and base by using the salt difference energy can efficiently utilize the ion migration generated Potential difference for acid-base production does not require energy storage and conversion systems, reducing energy loss in the process. By adjusting operating parameters, production capacity can be achieved while producing acid-base, and the process is simple without additional energy (except for pumping fluid). No pollution, high efficiency of acid and alkali production.

To achieve the above object, the technical scheme adopted in the present invention is as follows:

The present invention firstly discloses a reverse electrodialysis coupled bipolar membrane system based on salinity difference energy-driven production of acid and base, which is characterized in that: the reverse electrodialysis coupled bipolar membrane system includes a reverse electrodialysis coupled bipolar membrane device, feed liquid drive pump and feed liquid storage tank;

The reverse electrodialysis coupling bipolar membrane device is composed of a reverse electrodialysis coupling bipolar membrane stack and an anode plate and a cathode plate fixed on both sides of the reverse electrodialysis coupling bipolar membrane stack through splints; The feed liquid-driven pump includes an electrode liquid-driven pump, an acid-generating chamber solution-driven pump, an alkali-generating chamber solution-driven pump, a concentrated solution-driven pump, and a dilute solution-driven pump; the feed liquid storage tank includes an electrode liquid storage tank, an acid-generating chamber Solution storage tanks, solution storage tanks in alkali-generating room, concentrated solution storage tanks and dilute solution storage tanks;

The reverse electrodialysis coupled bipolar membrane stack is formed by alternately stacking the same number of cation exchange membranes and anion exchange membranes; The adjacent one is an anion exchange membrane; the flow channel grid and sealing gasket are placed between the anode plate and the adjacent cation exchange membrane to form the anode chamber, and the flow channel grid and sealing gasket are placed between the cathode plate and the adjacent anion exchange membrane Constitute the cathode chamber; between each pair of adjacent cation exchange membranes and anion exchange membranes, flow channel grids and sealing gaskets are placed alternately to form concentrated solution chambers and dilute solution chambers, and the concentrated solution chambers and dilute solution chambers are not less than one pair ; A bipolar membrane is inserted between any one or more pairs of adjacent cation exchange membranes and anion exchange membranes, and the anion exchange layer of the bipolar membrane faces the anode plate, the cation exchange layer faces the cathode plate, and the bipolar membrane Adjacent to the anion exchange layer is a cation exchange membrane, and adjacent to the cation exchange layer of the bipolar membrane is an anion exchange membrane, and a flow channel grid and a gasket are placed between the anion exchange layer of the bipolar membrane and the adjacent cation exchange membrane Alkali-generating chambers are formed by sheets, and flow channel grids and sealing gaskets are placed between the cation exchange layer of the bipolar membrane and the adjacent anion-exchange membrane to form an acid-generating chamber, and the alkali-generating chamber and the acid-generating chamber are not less than one pair;

The cathode plate is connected to the anode plate with a load;

The outlet of the anode chamber is connected to the inlet of the cathode chamber, and the anode chamber inlet and the outlet of the cathode chamber are fluidly communicated with the electrode liquid storage tank by an electrode solution driven pump; the acid generation chamber drives the pump through the solution of the acid generation chamber It is in fluid communication with the solution storage tank of the acid generation chamber, and the alkali generation chamber is fluidly connected with the solution storage tank of the alkali generation chamber by the solution drive pump of the alkali generation chamber; the concentrated solution storage tank is connected with the concentrated solution through the concentrated solution driven pump chamber in fluid communication; the dilute solution storage tank is in fluid communication with the dilute solution chamber via a dilute solution driven pump;

Both the acid generation room and the base generation room are equipped with pH meter measuring instruments.

in:

The anode plate and the cathode plate are selected from at least one of nickel sheet, titanium sheet, stainless steel sheet, foamed nickel sheet, foamed titanium sheet, nickel mesh, titanium mesh and stainless steel mesh coated with a catalyst on the surface, the The catalyst is at least one selected from platinum, ruthenium, iridium, cobalt, molybdenum and their oxides or sulfides.

The cation exchange membrane is selected from at least one of a common cation exchange membrane, a multivalent cation exchange membrane and a charged porous membrane; the anion exchange membrane is selected from a common anion exchange membrane, a multivalent anion exchange membrane and a charged porous membrane. At least one of the porous membranes; the bipolar membrane is selected from bipolar membranes prepared by a single-membrane method or a double-membrane method.

The drive pump can be in any form such as a diaphragm pump, a peristaltic pump, a centrifugal pump, a submersible pump, or a piston pump.

The method for producing acid-base by utilizing the above-mentioned reverse electrodialysis coupled bipolar membrane system is:

1) Add the concentrated solution and the weak solution to the concentrated solution storage tank and the weak solution storage tank respectively, add the initial acid-generating room solution to the acid-generating room solution storage tank, and add the initial alkali-generating room solution to the alkali-generating room solution Storage tank, adding the electrode solution to the electrode solution storage tank;

2) circulate the electrode solution in the electrode solution storage tank between the electrode solution storage tank and the anode chamber and the cathode chamber through the anode chamber inlet and the cathode chamber outlet; pass the initial acid generation chamber solution through the acid generation chamber inlet and acid-generating chamber outlet to circulate between the acid-generating chamber solution storage tank and the acid-generating chamber; the initial alkali-generating chamber solution is stored in the alkali-generating chamber solution via the alkali-generating chamber inlet and the alkali-generating chamber outlet circulation between the tank and the alkali-generating chamber;

3) introducing the concentrated solution in the concentrated solution storage tank and the dilute solution in the dilute solution storage tank into the concentrated solution chamber and the dilute solution chamber through the inlet of the concentrated solution chamber and the inlet of the dilute solution chamber respectively. The outlet of the solution chamber and the outlet of the dilute solution chamber are directly led out;

4) Connect the load, perform reverse electrodialysis to drive the bipolar membrane water dissociation operation, and the acid-generating chamber and the alkali-generating chamber continue to generate acid-base.

Wherein, the concentrated solution, the weak solution, the initial acid-generating chamber solution, the initial alkali-generating chamber solution, and the electrode solution are all aqueous solutions of strong electrolytes, and the concentration of strong electrolytes is not less than 0.01mol/L ; the strong electrolyte concentration of the concentrated solution is greater than the strong electrolyte concentration of the weak solution. The strong electrolyte is selected from at least one of lithium, sodium, potassium, chloride salts of ammonia ions, sulfates, nitrates, carbonates, phosphates, and organic acid salts.

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

The system provided by the present invention utilizes reverse electrodialysis coupling bipolar membrane to generate acid-base system, and utilizes the new renewable energy salt difference energy to directly prepare acid-base method. The potential energy difference of different concentrations of salt solutions in the chamber drives the bipolar membrane to dissociate water to generate protons and hydroxide ions, which can generate acid and alkali respectively in the chambers on both sides of the bipolar membrane. The system and its process can not only efficiently use the potential difference generated by ion migration for acid-base production, but also do not require energy storage and conversion, reducing energy loss in the process. By adjusting the operating parameters, it is possible to produce acid-base while increasing production capacity, and The process is simple, no additional energy is needed, no pollution, and the efficiency of acid and alkali production is high.

Description of drawings

Fig. 1 is the structural representation of reverse electrodialysis coupled bipolar membrane system provided by the present invention;

Fig. 2 is the working principle diagram of the reverse electrodialysis coupled bipolar membrane system provided by the present invention;

Fig. 3 is embodiment 1, 2 and 3 utilize reverse electrodialysis to drive bipolar membrane water dissociation to produce acid-base process in acid-generating chamber proton concentration change figure;

Numbers in the figure: 1 is the storage tank for the dilute solution; 1a is the inlet of the dilute solution chamber; 1b is the outlet of the dilute solution chamber; 1c is the pump driven by the dilute solution; 2 is the storage tank for the concentrated solution; 2a is the inlet of the concentrated solution chamber; Solution driven pump; 3 is electrode solution storage tank; 3a anode chamber inlet; 3b anode chamber outlet; 3c electrode solution driven pump; 3d cathode chamber inlet; 3e cathode chamber outlet; 4 is solution storage tank of alkali-generating chamber; 4a alkali-generating chamber Inlet; 4b outlet of alkali-generating chamber; 4c pump driven by solution of alkali-generating chamber; 5 is solution storage tank of acid-generating chamber; 5a inlet of acid-generating chamber; 5b outlet of acid-generating chamber; 5c pump driven by solution of acid-generating chamber; It is a reverse electrodialysis coupled bipolar membrane membrane stack; 8a is a pH meter for a solution in an alkali-generating chamber; 8b is a pH meter for a solution in an acid-generating chamber.

Detailed ways

The present invention will be described in further detail below in combination with specific embodiments. Other embodiments are contemplated and can be practiced without departing from the scope or spirit of the invention. Accordingly, the following detailed description is non-limiting.

Unless otherwise indicated, all numbers expressing characteristic dimensions, quantities and physical and chemical properties used in the specification and claims are to be understood as being modified in all instances by the term "about". Therefore, unless stated to the contrary, the numerical parameters listed in the foregoing specification and appended claims are all approximations, and those skilled in the art can use the teachings disclosed herein to seek to obtain the desired properties and make appropriate changes to these parameters. approximation. The use of numerical ranges by endpoints includes all numbers within that range and any range within that range, eg, 1 to 5 includes 1, 1.1, 1.3, 1.5, 2, 2.75, 3, 3.80, 4, and 5, etc. .

As shown in Figure 1, the present invention provides a reverse electrodialysis coupled bipolar membrane system, comprising a reverse electrodialysis coupled bipolar membrane device, a feed-liquid drive pump and a feed-liquid storage tank;

The reverse electrodialysis coupled bipolar membrane device is composed of a reverse electrodialysis coupled bipolar membrane stack and an anode plate and a cathode plate fixed on both sides of the reverse electrodialysis coupled bipolar membrane stack through splints; the feed liquid drive pump includes Electrode solution-driven pump, acid-generating room solution-driven pump, alkali-generating room solution-driven pump, concentrated solution-driven pump, dilute solution-driven pump; feed liquid storage tanks include electrode solution storage tanks, acid-generating room solution storage tanks, and alkali-generating room solution Storage tanks, concentrated solution storage tanks, and dilute solution storage tanks;

The reverse electrodialysis coupled bipolar membrane stack is composed of the same number and not less than two cation exchange membranes and anion exchange membranes stacked alternately in sequence; the cation exchange membrane is adjacent to the anode plate, and the cathode plate is adjacent to The anion exchange membrane is an anion exchange membrane; the flow channel grid and sealing gasket are placed between the anode plate and the adjacent cation exchange membrane to form the anode chamber, and the flow channel grid and sealing gasket are placed between the cathode plate and the adjacent anion exchange membrane to form the cathode chambers; each pair of adjacent cation exchange membranes and anion exchange membranes is placed between flow channel grids and sealing gaskets in turn to form concentrated solution chambers and dilute solution chambers, and there are no less than one pair of concentrated solution chambers and dilute solution chambers; A bipolar membrane is inserted between any one or more pairs of adjacent cation exchange membranes and anion exchange membranes, and the anion exchange layer of the bipolar membrane faces the anode plate, the cation exchange layer faces the cathode plate, and the anion exchange of the bipolar membrane The layer adjacent to the cation exchange membrane is the cation exchange membrane, and the anion exchange membrane is adjacent to the cation exchange layer of the bipolar membrane. The flow channel grid and the sealing gasket are placed between the anion exchange layer of the bipolar membrane and the adjacent cation exchange membrane. The alkali-generating chamber, the cation exchange layer of the bipolar membrane and the adjacent anion-exchange membrane are placed between the flow channel grid and the sealing gasket to form the acid-generating chamber, and the alkali-generating chamber and the acid-generating chamber shall not be less than one pair;

Wherein: there is no particular limitation on the specific type of the flow channel grid used, and various flow channel grids commonly used in this field can be used, and the specific size of the flow channel grid can be adjusted according to specific needs. In addition, there is no particular limitation on the material of the sealing gasket used, and various sealing gaskets commonly used in this field can be used, and the specific size of the sealing gasket can be adjusted according to specific needs.

The cathode plate is connected to the anode plate with a load;

The outlet of the anode chamber is connected to the inlet of the cathode chamber, and the anode chamber inlet and the outlet of the cathode chamber are fluidly communicated with the electrode liquid storage tank by an electrode solution driven pump; the acid generation chamber drives the pump through the solution of the acid generation chamber It is in fluid communication with the solution storage tank of the acid generation chamber, and the alkali generation chamber is fluidly connected with the solution storage tank of the alkali generation chamber by the solution drive pump of the alkali generation chamber; the concentrated solution storage tank is connected with the concentrated solution through the concentrated solution driven pump chamber in fluid communication; the dilute solution storage tank is in fluid communication with the dilute solution chamber via a dilute solution driven pump;

Both the acid generation room and the base generation room are equipped with pH meter measuring instruments.

A reverse electrodialysis coupled bipolar membrane system provided by the present invention will be described in detail below in conjunction with the accompanying drawings, but it should be pointed out that the accompanying drawings are only for exemplary purposes, and the technical solution of the present invention is by no means limited thereto .

Referring to FIG. 1 , FIG. 1 is a schematic structural diagram of a reverse electrodialysis coupled bipolar membrane system provided by the present invention. In Fig. 1: 1 is the dilute solution storage tank; 1a the inlet of the dilute solution chamber; 1b the outlet of the dilute solution chamber; 1c the dilute solution drives the pump; 2 is the concentrated solution storage tank; 2a the entrance of the dilute solution chamber; 2b the outlet of the dilute solution chamber; 2c Concentrated solution drives the pump; 3 is the electrode solution storage tank; 3a the anode chamber inlet; 3b the anode chamber outlet; 3c the electrode solution drives the pump; 3d the cathode chamber entrance; 3e the cathode chamber outlet; 4b is the outlet of the alkali-generating chamber; 4c is the pump driven by the solution of the alkali-generating chamber; 5 is the solution storage tank of the acid-generating chamber; 5a is the inlet of the acid-generating chamber; 5b is the outlet of the acid-generating chamber; 7 is a reverse electrodialysis coupled bipolar membrane stack; 8a is a pH meter for a solution in an alkali-generating chamber; 8b is a pH meter for a solution in an acid-generating chamber.

The cathode plate and the anode plate of the reverse electrodialysis coupling bipolar membrane device are connected to the load 6; the inlet 1a of the dilute solution chamber of the dilute solution chamber is connected to the dilute solution storage tank 1, and the inlet 2a of the concentrated solution chamber of the concentrated solution chamber is connected to the concentrated solution The storage tank 2, the outlet 1b of the weak solution chamber and the outlet 2b of the concentrated solution chamber are directly drawn; the anode chamber inlet 3a of the anode chamber and the cathode chamber outlet 3e of the cathode chamber are connected to the electrode solution storage tank 3, and the anode chamber outlet 3b of the anode chamber is connected to the cathode chamber The cathode chamber inlet 3d of the chamber is communicated through a silica gel tube; the alkali-generating chamber inlet 4a and the alkali-generating chamber outlet 4b of the alkali-generating chamber are communicated with the alkali-generating chamber solution storage tank 4, and the acid-generating chamber inlet 5a and the acid-generating chamber outlet of the acid-generating chamber 5b communicates with the solution storage tank 5 in the acid generation chamber.

The solutions in the concentrated solution chamber and the dilute solution chamber are respectively driven by driving pumps (concentrated solution driven pump 2c, dilute solution driven pump 1c), and are introduced into the corresponding concentrated solution chamber and dilute solution chamber in the reverse electrodialysis coupled bipolar membrane device from the corresponding solution storage tank. Solution chamber; the electrode chamber, alkali-generating chamber, and acid-generating chamber solutions are respectively driven by drive pumps (electrode solution-driven pump 3c, alkali-generating chamber solution-driven pump 4c, acid-generating chamber solution-driven pump 5c), and are coupled in reverse electrodialysis A circulating flow is formed between the bipolar membrane device and the corresponding solution storage tank;

Among them, the dilute solution-driven pump 1c, the concentrated solution-driven pump 2c, the electrode solution-driven pump 3c, the solution-driven pump 4c of the alkali-generating chamber, and the solution-driven pump 5c of the acid-generating chamber adopt peristaltic pumps.

pH meters (pH meter 8b for solution in the acid generation room and pH meter 8a for the solution in the base generation room) are all arranged at the solution storage tanks of the acid generation room and the solution storage tanks of the base generation room.

Specifically, the anode plate and the cathode plate are selected from at least one of nickel sheet, titanium sheet, stainless steel sheet, foamed nickel sheet, foamed titanium sheet, nickel mesh, titanium mesh and stainless steel mesh coated with a catalyst on the surface, and the catalyst At least one selected from platinum, ruthenium, iridium, cobalt, molybdenum and their oxides or sulfides.

Specifically, the cation exchange membrane is selected from at least one of a common cation exchange membrane, a multivalent cation exchange membrane and a charged porous membrane, and the anion exchange membrane is selected from a common anion exchange membrane, a multivalent anion exchange membrane and at least one of charged porous membranes, wherein the bipolar membrane is selected from bipolar membranes prepared by a single-membrane method or a double-membrane method.

The present invention also provides a method for producing acids and bases using the above-mentioned reverse electrodialysis coupled bipolar membrane system, comprising the following steps:

1) Add the concentrated solution and the weak solution to the concentrated solution storage tank and the weak solution storage tank respectively, add the initial acid-generating room solution to the acid-generating room solution storage tank, and add the initial alkali-generating room solution to the alkali-generating room solution Storage tank, adding strong electrolyte solution to the electrode solution storage tank;

2) circulate the electrode solution in the electrode solution storage tank between the electrode solution storage tank and the anode chamber and the cathode chamber through the anode chamber inlet and the cathode chamber outlet; pass the initial acid generation chamber solution through the acid generation chamber inlet and acid-generating chamber outlet to circulate between the acid-generating chamber solution storage tank and the acid-generating chamber; the initial alkali-generating chamber solution is stored in the alkali-generating chamber solution via the alkali-generating chamber inlet and the alkali-generating chamber outlet circulation between the tank and the alkali-generating chamber;

3) introducing the concentrated solution in the concentrated solution storage tank and the dilute solution in the dilute solution storage tank into the concentrated solution chamber and the dilute solution chamber through the inlet of the concentrated solution chamber and the inlet of the dilute solution chamber respectively. The outlet of the solution chamber and the outlet of the dilute solution chamber are directly led out;

4) Connect the load, perform reverse electrodialysis to drive the bipolar membrane water dissociation operation, and the acid-generating chamber and the alkali-generating chamber continue to generate acid-base.

Wherein: the concentrated solution, the light solution, the initial acid-generating chamber solution, the initial alkali-generating chamber solution and the electrode solution are all aqueous solutions of strong electrolytes, and the concentration of strong electrolytes is not less than 0.01mol/L ; the strong electrolyte concentration of the concentrated solution is greater than the strong electrolyte concentration of the weak solution. The strong electrolyte is selected from at least one of lithium, sodium, potassium, chloride salts of ammonia ions, sulfates, nitrates, carbonates, phosphates, and organic acid salts.

Wherein, the obtained acid and base can be collected and recovered after pH detection. The present invention has no special limitation on the collection and recovery method. Any method known to those skilled in the art will suffice.

The process principle of using reverse electrodialysis to drive bipolar membrane water dissociation to generate acids and bases provided by the present invention will be described in detail below with reference to FIG. 2 .

When the concentrated solution and the dilute solution enter the reverse electrodialysis membrane stack and flow in the concentrated solution chamber and the dilute solution chamber, driven by the concentration difference, the anions and cations in the concentrated solution chamber respectively migrate through the anion and cation exchange membranes into the dilute solution chamber, thereby forming an internal current and a potential difference for directional ion migration; part of the potential difference acts on the bipolar membrane. After the electronic load is connected, the bipolar membrane undergoes water dissociation to generate protons and hydroxide ions, making the ions in the membrane stack The migration is complete, and the ion migration current can be converted into the external circuit current of electron migration through the electrochemical reaction of the cathode and the anode to form a complete circuit.

The invention improves the traditional reverse electrodialysis device, introduces a bipolar membrane into the membrane stack, directly uses the salt difference to drive the bipolar membrane to generate acid and alkali, and can recover the acid and alkali. The system can not only efficiently use the potential difference generated by ion migration to directly produce acid and alkali, but also does not require energy storage and conversion systems, reducing energy loss in the process. By adjusting the operating parameters, it can achieve production capacity while producing acid and alkali, and the process Simple, no additional energy (except pumping fluid), no pollution, high efficiency of acid and alkali production.

In order to further understand the present invention, the reverse electrodialysis coupled bipolar membrane system and its production method based on salinity energy-driven production of acid and alkali provided by the present invention will be described below in conjunction with the examples. The protection scope of the present invention is not limited by the following examples.

Example 1

This embodiment utilizes the above-mentioned reverse electrodialysis coupled bipolar membrane system, the concentrated solution used is a sodium chloride solution with a concentration of 0.5mol/L, the light solution used is a sodium chloride solution with a concentration of 0.017mol/L, and the initial acid-generating chamber used The solution is a sodium chloride solution with a concentration of 0.5mol/L, the solution used in the initial alkali-generating chamber is a sodium chloride solution with a concentration of 0.5mol/L, and the electrode solution used is sodium chloride+potassium ferricyanide+potassium ferrocyanide (wherein the sodium chloride concentration is 0.5mol/L, the potassium ferricyanide concentration is 0.05mol/L, and the potassium ferrocyanide concentration is 0.05mol/L).

The reverse electrodialysis coupled bipolar membrane membrane stack is composed of an anode plate, a cathode plate, an anion exchange membrane, a cation exchange membrane, a bipolar membrane, a flow channel grid, and a sealing gasket in a certain order. A total of 21 cation exchange membranes and 21 anion exchange membranes are used, and 20 repeating units of "concentrated solution chamber-dilute solution chamber" are formed in the membrane stack. A total of one bipolar membrane is used to form an "alkali-generating chamber-acid generating chamber" in the membrane stack. The anode plate and cathode plate used in the process are ruthenium-coated titanium plates with a size of 9cm×21cm; the anion exchange membrane and cation exchange membrane used are respectively CJMC-1 and CJMA produced by Hefei Kejia Polymer Material Technology Co., Ltd. -1; the bipolar membrane used is Neosepta BPM-1 from Tokuyama Corporation, Japan, and its cut size is 9cm×21cm; the effective area of a single membrane and a single electrode of a membrane stack is 189cm ² .

In this embodiment, the operation of using reverse electrodialysis to drive bipolar membrane water dissociation to generate acid and base is carried out according to the following steps:

1) Add 0.5mol/L sodium chloride concentrated solution and 0.017mol/L sodium chloride light solution to the concentrated solution storage tank and light solution storage tank respectively, and add 0.5mol/L sodium chloride initial acid generation chamber solution to Acid-generating chamber solution storage tank, add 0.5mol/L sodium chloride initial alkali-generating chamber solution to the alkali-generating chamber solution storage tank, add 0.5mol/L sodium chloride+0.05mol/L potassium ferricyanide+0.05mol/ L potassium ferrocyanide solution is added to the electrode solution storage tank;

2) Make the electrode liquid in the electrode liquid storage tank circulate between the catholyte storage tank and the cathode and the anode chamber via the anode chamber inlet and the cathode chamber outlet, with a flow rate of 0.075 L/min;

The initial alkali-generating chamber solution in the alkali-generating chamber solution storage tank is circulated between the alkali-generating chamber solution storage tank and the alkali-generating chamber through the alkali-generating chamber inlet and the alkali-generating chamber outlet, and the flow rate is 0.075L/min;

The initial acid generation chamber solution in the acid generation chamber solution storage tank is circulated between the acid generation chamber solution storage tank and the acid generation chamber via the acid generation chamber inlet and the acid generation chamber outlet at a flow rate of 0.075 L/min;

3) Introduce the concentrated solution in the concentrated solution storage tank and the weak solution in the weak solution storage tank into the concentrated solution chamber and the dilute solution chamber respectively, with a flow rate of 0.15 L/min;

4) Connect the anode plate and the cathode plate to an external load, perform reverse electrodialysis to drive the bipolar membrane to generate acid and alkali, and record the current and voltage over time through the programmable electronic load device between the anode plate and the cathode plate The change;

The solutions in the acid-generating chamber and the alkali-generating chamber enter the acid-generating chamber solution storage tank and the alkali-generating chamber solution storage tank respectively, and are detected online by a pH meter.

Measure the current in the acid-base production process of this embodiment by the above programmable electronic load device, and detect the change of the acid production rate by the pH meter device, the results are shown in Fig. 3 and table 1, wherein Fig. 3 is embodiment 1, 2 and 3 Diagram of the change of proton concentration in the acid-generating chamber during the process of driving bipolar membrane water dissociation to generate acid-base by reverse electrodialysis; Table 1 is the process of using reverse electrodialysis to drive bipolar membrane water dissociation to generate acid-base in the process of embodiment 1, 2 and 3 Current, acid production rate and correlation coefficient R ² .

In this experiment, the system can continuously generate current, and can detect a stable acid-base production rate of 3.2mmol/h.

Example 2

Acid-base was directly produced by the same system shown in FIG. 1 in a similar manner to Example 1, except that the concentration of sodium chloride in the concentrated solution was changed to 1.5 mol/L.

Measure the change of the current and the rate of acid-base generation in the process of acid-base generation in this embodiment, and the results are shown in Figure 3 and Table 1. In this experiment, the system can continuously generate current, and can detect a stable acid-base production rate of 3.3mmol/h.

Example 3

An acid-base was directly produced by the same system shown in FIG. 1 in a similar manner to Example 1, except that the concentration of sodium chloride in the concentrated solution was changed to 3.0 mol/L.

Measure the change of the current and the rate of acid-base generation in the process of acid-base generation in this embodiment, and the results are shown in Figure 3 and Table 1. In this experiment, the system can continuously generate current, and can detect a stable acid-base production rate of 3.3mmol/h.

Table 1

HC/LC Current (A) Acid production rate (mmol/h) R ² 0.5M/0.017M 0.15 3.2 99.6 1.5M/0.017M 0.18 3.3 99.0 3.0M/0.017M 0.21 3.3 98.6

Claims (6)

1. A reverse electrodialysis coupled bipolar membrane system based on salt difference energy-driven production of acid and base, characterized in that: the reverse electrodialysis coupled bipolar membrane system comprises a reverse electrodialysis coupled bipolar membrane device, a material Liquid-driven pumps and storage tanks for feed liquid; The reverse electrodialysis coupling bipolar membrane device is composed of a reverse electrodialysis coupling bipolar membrane stack and an anode plate and a cathode plate fixed on both sides of the reverse electrodialysis coupling bipolar membrane stack through splints; The feed liquid-driven pump includes an electrode liquid-driven pump, an acid-generating chamber solution-driven pump, an alkali-generating chamber solution-driven pump, a concentrated solution-driven pump, and a dilute solution-driven pump; the feed liquid storage tank includes an electrode liquid storage tank, an acid-generating chamber Solution storage tanks, solution storage tanks in alkali-generating room, concentrated solution storage tanks and dilute solution storage tanks; The reverse electrodialysis coupled bipolar membrane stack is formed by alternately stacking the same number of cation exchange membranes and anion exchange membranes; The adjacent one is an anion exchange membrane; the flow channel grid and sealing gasket are placed between the anode plate and the adjacent cation exchange membrane to form the anode chamber, and the flow channel grid and sealing gasket are placed between the cathode plate and the adjacent anion exchange membrane Constitute the cathode chamber; between each pair of adjacent cation exchange membranes and anion exchange membranes, flow channel grids and sealing gaskets are placed alternately to form concentrated solution chambers and dilute solution chambers, and the concentrated solution chambers and dilute solution chambers are not less than one pair ; A bipolar membrane is inserted between any one or more pairs of adjacent cation exchange membranes and anion exchange membranes, and the anion exchange layer of the bipolar membrane faces the anode plate, the cation exchange layer faces the cathode plate, and the bipolar membrane Adjacent to the anion exchange layer is a cation exchange membrane, and adjacent to the cation exchange layer of the bipolar membrane is an anion exchange membrane, and a flow channel grid and a gasket are placed between the anion exchange layer of the bipolar membrane and the adjacent cation exchange membrane Alkali-generating chambers are formed by sheets, and flow channel grids and sealing gaskets are placed between the cation exchange layer of the bipolar membrane and the adjacent anion-exchange membrane to form an acid-generating chamber, and the alkali-generating chamber and the acid-generating chamber are not less than one pair; The cathode plate is connected to the anode plate with a load; The outlet of the anode chamber is connected to the inlet of the cathode chamber, and the anode chamber inlet and the outlet of the cathode chamber are fluidly communicated with the electrode liquid storage tank by an electrode solution driven pump; the acid generation chamber drives the pump through the solution of the acid generation chamber It is in fluid communication with the solution storage tank of the acid generation chamber, and the alkali generation chamber is fluidly connected with the solution storage tank of the alkali generation chamber by the solution drive pump of the alkali generation chamber; the concentrated solution storage tank is connected with the concentrated solution through the concentrated solution driven pump chamber in fluid communication; the dilute solution storage tank is in fluid communication with the dilute solution chamber via a dilute solution driven pump; Both the acid generation room and the base generation room are equipped with pH meter measuring instruments. 2. reverse electrodialysis coupled bipolar membrane system according to claim 1, is characterized in that: described anode plate and described cathode plate are selected from the nickel sheet that surface is coated with catalyst, titanium sheet, stainless steel sheet, foam At least one of nickel sheet, foamed titanium sheet, nickel mesh, titanium mesh and stainless steel mesh, the catalyst is at least one selected from platinum, ruthenium, iridium, cobalt, molybdenum and their oxides or sulfides. 3. reverse electrodialysis coupled bipolar membrane system according to claim 1, is characterized in that: described cation exchange membrane is selected from at least one in common cation exchange membrane, a polyvalent cation exchange membrane and charged porous membrane The anion-exchange membrane is selected from at least one of common anion-exchange membranes, a polyvalent anion-exchange membrane, and a charged porous membrane; . 4. A method utilizing the reverse electrodialysis coupling bipolar membrane system described in any one of claims 1 to 3 to produce acid-base, is characterized in that, comprises the steps: 1) Add the concentrated solution and the weak solution to the concentrated solution storage tank and the weak solution storage tank respectively, add the initial acid-generating room solution to the acid-generating room solution storage tank, and add the initial alkali-generating room solution to the alkali-generating room solution Storage tank, adding the electrode solution to the electrode solution storage tank; 2) circulate the electrode solution in the electrode solution storage tank between the electrode solution storage tank and the anode chamber and the cathode chamber through the anode chamber inlet and the cathode chamber outlet; pass the initial acid generation chamber solution through the acid generation chamber inlet and acid-generating chamber outlet to circulate between the acid-generating chamber solution storage tank and the acid-generating chamber; the initial alkali-generating chamber solution is stored in the alkali-generating chamber solution via the alkali-generating chamber inlet and the alkali-generating chamber outlet circulation between the tank and the alkali-generating chamber; 3) introducing the concentrated solution in the concentrated solution storage tank and the dilute solution in the dilute solution storage tank into the concentrated solution chamber and the dilute solution chamber through the inlet of the concentrated solution chamber and the inlet of the dilute solution chamber respectively. The outlet of the solution chamber and the outlet of the dilute solution chamber are directly led out; 4) Connect the load, perform reverse electrodialysis to drive the bipolar membrane water dissociation operation, and the acid-generating chamber and the alkali-generating chamber continue to generate acid-base. 5. method according to claim 4, it is characterized in that: described concentrated solution, described light solution, described initial acid generation room solution, described initial base generation room solution and described electrode liquid are strong electrolyte An aqueous solution with a strong electrolyte concentration of not less than 0.01mol/L; the strong electrolyte concentration of the concentrated solution is greater than that of the weak solution. 6. The method according to claim 5, characterized in that: said strong electrolyte is selected from the group consisting of lithium, sodium, potassium, ammonium ions in chlorine salts, sulfates, nitrates, carbonates, phosphates, organic acid salts at least one of .