CN104674382B - Preparation method of porous carbon nanofiber for capacitive deionization - Google Patents

Abstract

The invention relates to a preparation method of porous carbon nanofibers for capacitive deionization, comprising: (1) dissolving a carbon precursor, an organic pore-forming agent, and a transition metal salt in a solvent to obtain a spinning solution; (2) dissolving the above-mentioned Electrospinning is performed on the spinning solution to obtain composite nanofibers, which are then pre-oxidized, carbonized and pickled sequentially to obtain porous carbon nanofibers. The carbon nanofibers prepared by the present invention are rich in mesoporous and microporous structures, have high specific surface area, good flexibility, low resistance, good wettability, excellent performance in forming electric double layers, and are very suitable for assembling capacitors and for desalination.

Description

A preparation method of porous carbon nanofibers for capacitive deionization

technical field

The invention belongs to the field of nanofibers, in particular to a method for preparing porous carbon nanofibers for capacitive deionization.

Background technique

As we all know, water is the source of life, and the global scarcity of fresh water resources is a key factor restricting the economic development of many countries, and it is closely related to people's daily life. Brackish water is rich in content and is an important water source to solve the shortage of fresh water resources. So far, people have developed a variety of deionization technologies such as distillation, electrodialysis, reverse osmosis, activated carbon adsorption, and ion exchange for desalination of brackish water. However, distillation and reverse osmosis are energy-intensive processes. The electrodialysis process will generate gas due to electrolysis, which has potential safety hazards. The regeneration process of activated carbon adsorbents, membranes, and ion exchange resins is expensive and may cause secondary pollution. The shortage of fresh water resources forces us to develop an ideal process with high efficiency, low energy consumption, no pollution, simple regeneration and safety as soon as possible.

Capacitors are a new type of energy storage element developed at home and abroad in recent decades. They have the advantages of high current charge and discharge, high charge and discharge efficiency, good performance cycle stability, high specific power, and no pollution. Therefore, the supercapacitor is an efficient, practical, environmentally friendly, and low-cost energy storage device, and it is also a new type of energy-saving brine desalination device. Porous materials with a large specific surface area are used as electrodes, and the electric double layer capacitance is used to adsorb ions in the solution so as to achieve the purpose of removing ions in the brine.

At present, the research hotspots of capacitive desalination mainly focus on the development of electrode materials with high specific energy and high specific power. Carbon materials are commonly used electrode materials due to their high specific surface area and good electric double layer capacitance performance. Research on carbon materials mainly focuses on porous carbon materials with high specific surface area and low internal resistance, and research on the modification of carbon-based materials. Commonly used carbon materials include activated carbon, carbon nanotubes, carbon aerogels, carbon black, and carbon nanofibers. Among numerous carbon materials, activated carbon, carbon nanotubes and carbon aerogels are considered to be promising new carbon materials.

Although activated carbon has a large specific surface area, its micropores are mostly (pore diameter <2nm), which contributes little to the electric double layer. It is difficult for many hydrated ions to reversibly enter and exit the micropores, and the capacitive deionization efficiency is low. However, carbon nanotubes are difficult to disperse uniformly, and there are certain defects after modification, which limits the further application of carbon nanotubes. Carbon airgel has good electrical conductivity and more mesoporous structure, which is conducive to the transmission and diffusion of ions. It is an ideal electrode material for supercapacitors, but the preparation cost is high and it is not easy to mass-produce.

Electrospinning technology is the simplest and most effective ideal method for preparing nanofibers (diameter range of 50-500nm). The prepared nanofibers have high specific surface area and uniform fiber diameter, which are more suitable for preparing carbon nanofiber materials. However, the porosity of the resulting carbon nanofibers is relatively low, requiring physical activation ( _CO2 activation, water vapor activation) or chemical activation (ZnCl2 activation, _KOH activation, etc.), so the development of simple high mesoporous, microporous carbon nanofibers The preparation method of the fiber is still the key to improve the capacitive deionization performance.

Contents of the invention

The technical problem to be solved by the present invention is to provide a method for preparing porous carbon nanofibers for capacitive deionization. The carbon nanofibers prepared by this method are rich in mesopores and microporous structures, have high specific surface area, good flexibility and low resistance. , Good wettability, excellent performance in forming electric double layer, very suitable for assembling capacitors and desalination.

A method for preparing porous carbon nanofibers for capacitive deionization of the present invention, comprising:

(1) Dissolving the carbon precursor, organic pore-forming agent, and transition metal salt in a solvent to obtain a spinning solution; wherein, the mass fraction of the carbon precursor is 5-20%, and the mass fraction of the organic pore-forming agent is 1-20%. 20%, the mass fraction of transition metal salt is 0-10%;

(2) Electrospinning the above spinning solution to obtain composite nanofibers, followed by pre-oxidation, carbonization and pickling in sequence to obtain porous carbon nanofibers.

The carbon precursor in the step (1) is one or more of polyacrylonitrile PAN, polybenzimidazole PBI, acrylonitrile and styrene copolymer, acrylonitrile and methyl acrylate binary copolymer .

The organic pore-forming agent in the step (1) is one or more of polymethyl methacrylate PMMA, polylactic acid PLA, and polystyrene PS.

The transition metal salt in the step (1) is one or more of halides, acetates, phosphates, and sulfates of zinc, iron, nickel, copper, and manganese.

The solvent in the step (1) is one or more of N,N-dimethylformamide DMF and N,N-dimethylacetamide DMAC.

The electrospinning process parameters in the step (2) are: the spinning voltage is 10-25kV, the receiving distance is 10-25cm, the flow rate of spinning solution is 0.2-2ml/h, and the humidity is controlled at 30-50%. .

The pre-oxidation in the step (2) is as follows: in an air atmosphere, the temperature is raised to 240-280°C at 0.5-2°C/min, and after maintaining for 90-120min, the furnace is cooled to room temperature; carbonization is: in nitrogen or argon Under air atmosphere, heat up to 700-1000°C at a rate of 2-10°C/min, and maintain for 90-120min, then cool to room temperature in the furnace under nitrogen or argon atmosphere; pickling: soak in acid solution for 8-24h , rinse the nanofibers with pure water to remove the transition metal salts on the surface of the fibers.

The acid is one or more of hydrochloric acid, nitric acid, sulfuric acid and phosphoric acid.

The porous carbon nanofiber obtained in the step (2) is used as a self-supporting electrode for assembling a capacitor, specifically: the capacitor contains one or more electrode pairs composed of two symmetrically sized porous carbon nanofibers, the outermost The electrodes are in contact with the current collector and connected to a DC power supply; a plastic mesh is inserted between the two electrodes of the same electrode pair to separate them as a fluid channel; an inert conductive plate is inserted between the electrodes of the adjacent electrode pair to prevent ion exchange with different charges on both sides ; All electrode pairs are connected in series to the DC power supply, and all fluid channels are connected in parallel to the inlet and outlet.

The current collector is one or more of titanium mesh, titanium sheet, graphite sheet, conductive graphite paper, stainless steel sheet, copper sheet, conductive carbon cloth; the inert conductive plate is titanium sheet, graphite sheet, conductive graphite paper , stainless steel sheet, copper sheet or one or more.

The capacitor is applied to a salt water desalination system; wherein, the salt water desalination system includes a water storage tank, an intelligent control constant current pump, a capacitor, a DC power supply, a system control, a conductivity meter, and a concentration pool.

The DC power supply can control the charging and discharging process of the capacitor.

The conductivity meter can monitor and record the quality of effluent water in real time.

The constant flow pump is used to control the flow rate of water, and can automatically switch on and off according to the charging and discharging signals.

Using the prepared porous carbon nanofibers as self-supporting electrodes to assemble a capacitor desalination device containing self-supporting electrode pairs, the method is as follows:

As shown in Figure 2, the porous self-supporting single-electrode pair capacitor (hereinafter referred to as: single-electrode pair capacitor) is separated by a plastic mesh as a fluid channel between the two electrode materials, and the two electrodes are connected to the positive and negative poles of the DC power supply through the current collector. The supercapacitor is sealed and fixed with an acrylic plate and a silicone gasket.

As shown in Figure 3, in a porous self-supporting multi-electrode pair supercapacitor (hereinafter referred to as multi-electrode pair capacitor), a plastic mesh is inserted between the two electrodes of the same electrode pair to separate them as a fluid channel; the electrodes on both sides are connected to DC through the current collector. The positive and negative poles of the power supply; an inert conductive plate is sandwiched between the electrode materials of adjacent electrode pairs to prevent the exchange of ions with different charges on both sides and ensure the current path. The supercapacitor is sealed and fixed with an acrylic plate and a silicone pad; each electrode pair is connected to a DC power supply in series, and the fluid channel is connected to the inlet and outlet in parallel.

The invention also assembles a single-electrode pair capacitor test system for ion removal in salt water. As shown in Figure 4, a single-electrode pair capacitor as shown in Figure 2 is used, and the water inlet and outlet holes of the capacitor are connected to a constant current pump and a water storage tank for solution circulation; the two electrodes of the capacitor are connected to a constant current power supply to control the capacitor During the charging and self-discharging process, the adsorption and desorption of ions in the brine is realized, and the conductivity meter monitors the water quality of the solution in real time.

The invention also assembles an application system for removing ions in salt water by assembling a multi-electrode pair supercapacitor bank. As shown in Figure 5, multiple multi-electrode pair capacitors as shown in Figure 3 are used. The capacitors are connected in series, parallel, and mixed to form a capacitor bank connected to the water inlet and outlet. The capacitor bank is connected in series, parallel, and mixed. The mode is connected to the positive and negative poles of the DC power supply; the water inlet and outlet of the capacitor are connected to the dual-channel self-control constant-flow pump and the water storage tank and the concentration tank to carry out the flow of purified water and the circulation of the concentrate; the conductivity meter monitors the solution in real time Water quality conditions to ensure the normal operation of the system.

Beneficial effect

(1) The present invention adopts carbon precursor, organic pore forming agent, the carbon nanofiber prepared by compounding of transition metal salt is rich in mesopore, microporous structure, because transition metal compound can adjust organic pore forming agent such as PMMA or PS and PAN The degree of phase separation, so the obtained nanofiber pore structure can be effectively controlled, with high specific surface area, good flexibility, low resistance, good wettability, and excellent performance in forming an electric double layer, which is very suitable for assembling capacitors and for desalination;

(2) In the present invention, self-supporting porous carbon nanofiber electrodes are used to assemble a supercapacitor, which is simple to assemble, low in cost, and has a long operating life. It is suitable for desalination of brackish water and has a good market application prospect.

Description of drawings

Fig. 1 is the SEM figure of the porous carbon nanofiber prepared by the present invention, and the electrospinning nanofiber formula is (a) PAN:PMMA:Zn(Ac) ₂ =4:1:1, (b) PAN:PMMA=4:1; (c) PAN:PS:ZnCl ₂ =8:2:1, (d) PAN:PS=8:2; the illustration shows the cross-sectional morphology of porous carbon nanofibers;

Figure 2 is a single-electrode pair supercapacitor;

Figure 3 is a multi-electrode pair supercapacitor;

Figure 4 is a single-electrode pair capacitor deionization test system; wherein 1 is a water storage tank; 2 is a constant current pump; 3 is a single-electrode supercapacitor; 4 is a DC power supply; 5 is a system control; 6 is a conductivity meter;

Figure 5 is a multi-electrode pair capacitor bank deionization application system; 1 is a water storage tank; 2 is an intelligent control constant current pump; 3 is a multi-electrode super capacitor bank; 4 is a DC power supply; 5 is a system control; 6 is a conductivity meter ; 7 is the concentration pool;

Fig. 6 is the voltage-current variation curve in the charging and discharging cycle of the capacitor;

Fig. 7 is PAN/PMMA/Zn(Ac) _2The change curve diagram of NaCl solution conductivity in the charge-discharge cycle of capacitor;

Fig. 8 is the change curve diagram of NaCl solution conductivity in PAN/PMMA capacitor charge-discharge cycle;

Fig. 9 is PAN/PS/ZnClThe change curve of _NaCl solution conductivity in the charge-discharge cycle of capacitor;

Fig. 10 is a curve diagram of the change of conductivity of NaCl solution in the charging and discharging cycle of PAN/PS capacitor.

detailed description

Below in conjunction with specific embodiment, further illustrate the present invention. It should be understood that these examples are only used to illustrate the present invention and are not intended to limit the scope of the present invention. In addition, it should be understood that after reading the teachings of the present invention, those skilled in the art can make various changes or modifications to the present invention, and these equivalent forms also fall within the scope defined by the appended claims of the present application.

Example 1

Using PAN as the carbon precursor, polymethyl methacrylate (PMMA) as the pore-forming agent, adjusting the mass ratio of PAN, PMMA and Zn(Ac) ₂ to 4:1:1, and preparing a total mass fraction of 12% The spinning solution is moved into the syringe, the electrospinning voltage is set to be 15kV, the spinning distance is 15cm, the spinning solution injection speed is 0.5ml/min, and the humidity is controlled at about 35%, and the electrospinning preparation PAN/PMMA/Zn( Ac) ₂ fiber precursors. The fiber precursors were pre-oxidized in an air atmosphere, the temperature was programmed to rise to 260°C at 1°C/min, and maintained at 260°C for 90 minutes, then cooled naturally. Carry out carbonization treatment under nitrogen atmosphere, raise the temperature to 800°C at 5°C/min, maintain for 90min, and cool down. Soak in 0.5M hydrochloric acid for 24 hours, rinse with pure water to remove transition metal salts on the fiber surface. Due to the incompatibility of PAN and PMMA, phase separation is formed during the spinning process. Zn(Ac) ₂ can adjust the phase separation state of the two. After the heat treatment process, PMMA decomposes and disappears, and Zn(Ac) ₂ has catalytic, Activation, after pickling treatment, porous carbon nanofibers are obtained, as shown in Figure 1-a, with a specific surface area of 468.0m ² /g. Cut the treated fibers into electrodes with a size of 5 cm × 6 cm, soak them in 500 ppm NaCl solution for 24 hours, and then assemble supercapacitor devices as self-supporting electrodes as shown in Figure 2. Assemble the supercapacitor, DC power supply, constant current pump, conductivity meter, and water storage tank as shown in Figure 4 into a deionization test system. The water inlet and outlet of the capacitor are connected to a constant current pump and a water storage tank for solution circulation. Before the test, the water storage tank is 500ppm NaCl solution; the two electrodes of the capacitor are connected to the constant current power supply through the current collector, and the capacitor is controlled in the mode shown in Figure 6 The charging and discharging cycle realizes the adsorption and desorption of ions in salt water. Fig. 7 is the change curve of the conductivity in the NaCl solution during the charge-discharge cycle. Its average single-cycle desalination capacity is 24.5mg/g.

Comparative example 1

With PAN as the carbon precursor, polymethyl methacrylate (PMMA) as the pore-forming agent, adjust the mass ratio of PAN and PMMA to be 4:1, prepare a DMF spinning solution with a total mass fraction of 10%, and transfer the solution into a syringe In the process, the electrospinning voltage is set to 15kV, the spinning distance is 15cm, the spinning liquid injection speed is 1ml/min, and the humidity is controlled below 35%. The PAN/PMMA composite nanofiber material is prepared by electrospinning, and the nanofiber is placed in the air. Pre-oxidation was carried out under the atmosphere, and the temperature was programmed to rise to 260°C at a rate of 1°C/min, and then cooled naturally at 260°C for 90 minutes. Carry out carbonization treatment under nitrogen atmosphere, raise the temperature to 800°C at 5°C/min, maintain for 90min, and cool down. Due to the incompatibility between PAN and PMMA, phase separation is formed during the spinning process. After heat treatment, PMMA decomposes and disappears to form porous carbon nanofibers, as shown in Figure 1-b. However, due to the lack of transition metal salts, PAN and The regulation of phase separation of PMMA resulted in many pores with relatively large pore size and uneven distribution. In addition, the content of micropores decreased, so its specific surface area was 275.8m ² /g. Cut the porous carbon nanofibers into electrodes with a size of 5cm×6cm, soak them in 500ppm NaCl solution for 24 hours, and assemble capacitors as self-supporting electrodes as shown in Figure 2. Assemble the capacitor, DC power supply, constant current pump, conductivity meter, and water storage tank as shown in Figure 4 into a capacitor desalination system. The water inlet and outlet of the capacitor are connected to a constant current pump and a water storage tank for solution circulation. Before the test, the water storage tank is 500ppm NaCl solution; the two electrodes of the capacitor are connected to the constant current power supply through the current collector, and the capacitor is controlled in the mode shown in Figure 6 The charge-discharge cycle realizes the adsorption and desorption of ions in salt water. Fig. 8 is the change curve of the conductivity in the NaCl solution during the charge-discharge cycle. Due to the relatively low specific surface area and relatively uneven pore size distribution, the average single-cycle desalination capacity is greatly reduced and can only reach the level of 5.6mg/g.

Example 2

Using PAN as a carbon precursor, polystyrene (PS) as a pore-forming agent, adjusting the mass ratio of PAN, PS and ZnCl to 8: ₂ :1, preparing a spinning solution with a total mass fraction of 11%, and moving it into a syringe, Set the electrospinning voltage to 12kV, the spinning distance to 15cm, the spinning solution injection speed to 0.5ml/min, and the humidity to be controlled at about 30%, to prepare PAN/PS/ _ZnCl2 fiber precursors by electrospinning. The fiber precursors were pre-oxidized in an air atmosphere, and the temperature was programmed to increase at a rate of 1 °C/min to 250 °C, and maintained at 250 °C for 100 min and then cooled naturally. Carry out carbonization treatment under nitrogen atmosphere, raise the temperature to 800°C at 5°C/min, maintain for 120min, and cool down. Soak in 0.5M hydrochloric acid for 18 hours, rinse with pure water to remove transition metal salts on the fiber surface. Due to the incompatibility of PAN and PS, phase separation is formed during the spinning process. ZnCl ₂ can adjust the phase separation state of the two. After heat treatment, PS decomposes and disappears, and ZnCl ₂ has catalytic and activation functions. That is, porous carbon nanofibers, as shown in Figure 1-c, have a specific surface area of 400.7m ² /g. Cut the treated fibers into electrodes with a size of 5 cm × 6 cm, soak them in 500 ppm NaCl solution for 24 hours, and then assemble supercapacitor devices as self-supporting electrodes as shown in Figure 2. Assemble the supercapacitor, DC power supply, constant current pump, conductivity meter, and water storage tank as shown in Figure 4 into a deionization test system. The water inlet and outlet of the capacitor are connected to a constant flow pump and a water storage tank for solution circulation. Before the test, the water storage tank is 500ppm NaCl solution. The two electrodes of the capacitor are connected to the constant current power supply through the current collector, and the charging and discharging cycle of the capacitor is controlled in the mode shown in Figure 6, so as to realize the adsorption and desorption of ions in the salt water. Fig. 9 is the change curve of the conductivity in the NaCl solution during the charge-discharge cycle. Its average single cycle desalination capacity is 21.8mg/g.

Comparative example 2

With PAN as the carbon precursor, polystyrene (PS) as the pore-forming agent, adjust the mass ratio of PAN and PS to 8:2, prepare a DMF spinning solution with a total mass fraction of 10%, move the solution into a syringe, and set up the electrospinning solution. The wire voltage is 12kV, the spinning distance is 15cm, the spinning liquid injection speed is 0.5ml/min, and the humidity is controlled below 30%. The PAN/PS composite nanofiber material is prepared by electrospinning, and the nanofiber is placed in an air atmosphere for pretreatment. Oxidation, controlled temperature program, raised to 250°C at a rate of 1°C/min, and maintained at 250°C for 90 minutes, then cooled naturally. Carry out carbonization treatment under nitrogen atmosphere, raise the temperature to 800°C at 5°C/min, maintain for 120min, and cool down. Due to the incompatibility between PAN and PS, phase separation is formed during the spinning process. After heat treatment, PS decomposes and disappears to form porous carbon nanofibers, as shown in Figure 1-d. However, due to the absence of transition metal salts, PAN and PS The regulation of phase separation of PMMA resulted in many pores with relatively large pore size and uneven distribution. In addition, the content of micropores decreased, so its specific surface area was 39.83m ² /g. Cut the porous carbon nanofibers into electrodes with a size of 5cm×6cm, soak them in 500ppm NaCl solution for 24 hours, and assemble capacitors as self-supporting electrodes as shown in Figure 2. Assemble the capacitor, DC power supply, constant current pump, conductivity meter, and water storage tank as shown in Figure 4 into a capacitor desalination system. The water inlet and outlet of the capacitor are connected to a constant current pump and a water storage tank for solution circulation. Before the test, the water storage tank is 500ppm NaCl solution; the two electrodes of the capacitor are connected to the constant current power supply through the current collector, and the capacitor is controlled in the mode shown in Figure 6 The charge-discharge cycle realizes the adsorption and desorption of ions in salt water. Fig. 10 is the change curve of the conductivity in the NaCl solution during the charge-discharge cycle. Due to the relatively low specific surface area and relatively uneven pore size distribution, the average single-cycle desalination capacity is greatly reduced, only reaching the level of 2.8 mg/g, and the cycle stability is relatively poor.

Claims (10)

1. A method for preparing porous carbon nanofibers for capacitive deionization, comprising: (1) Dissolving the carbon precursor, organic pore-forming agent, and transition metal salt in a solvent to obtain a spinning solution; wherein, the mass fraction of the carbon precursor is 5-20%, and the mass fraction of the organic pore-forming agent is 1-20%. 20%, the mass fraction of transition metal salt is 0-10%; (2) Electrospinning the above spinning solution to obtain composite nanofibers, followed by pre-oxidation, carbonization, and pickling to obtain porous carbon nanofibers; wherein the organic pore-forming agent is polymethyl methacrylate One or more of PMMA, polylactic acid PLA, polystyrene PS. 2. the preparation method of a kind of capacitive deionization porous carbon nanofiber according to claim 1 is characterized in that: the carbon precursor in the described step (1) is polyacrylonitrile PAN, polybenzimidazole PBI, One or more of acrylonitrile and styrene copolymers, acrylonitrile and methyl acrylate binary copolymers. 3. the preparation method of a kind of capacitive deionization porous carbon nanofiber according to claim 1 is characterized in that: the transition metal salt in the described step (1) is the halide of zinc, iron, nickel, copper, manganese One or more of substances, acetates, phosphates, and sulfates. 4. the preparation method of a kind of capacitive deionization porous carbon nanofiber according to claim 1, is characterized in that: the solvent in the described step (1) is N, N-dimethylformamide DMF, N, One or more of N-dimethylacetamide DMAC. 5. the preparation method of a kind of capacitive deionization porous carbon nanofiber according to claim 1 is characterized in that: the electrospinning process parameter in the described step (2) is: spinning voltage is 10-25kV, The receiving distance is 10-25cm, the flow rate of spinning solution is 0.2-2ml/h, and the humidity is controlled at 30-50%. 6. A method for preparing porous carbon nanofibers for capacitive deionization according to claim 1, characterized in that: the pre-oxidation in the step (2) is: in an air atmosphere at 0.5-2 °C/min Raise the temperature to 240-280°C and maintain it for 90-120 minutes, then cool the furnace to room temperature; carbonization: in nitrogen or argon atmosphere, heat up to 700-1000°C at a rate of 2-10°C/min, and maintain 90- After 120 minutes, cool in the furnace to room temperature under a nitrogen or argon atmosphere; pickling: immerse in an acid solution for 8-24 hours, rinse the nanofibers with pure water to remove transition metal salts on the surface of the fibers. 7 . The method for preparing porous carbon nanofibers for capacitive deionization according to claim 6 , wherein the acid is one or more of hydrochloric acid, nitric acid, sulfuric acid, and phosphoric acid. 8. a kind of preparation method of capacitive deionization according to claim 1 uses porous carbon nanofiber, it is characterized in that: the porous carbon nanofiber that described step (2) obtains is used for assembling capacitor as self-supporting electrode, specifically : The capacitor contains one or more electrode pairs composed of two symmetrical porous carbon nanofibers, the outermost electrode is in contact with the current collector and connected to a DC power supply; a plastic mesh is inserted between the two electrodes of the same electrode pair Open as a fluid channel; an inert conductive plate is sandwiched between the electrodes of adjacent electrode pairs to prevent ion exchange with different charges on both sides; all electrode pairs are connected in series to a DC power supply, and all fluid channels are connected in parallel to the inlet and outlet. 9. the preparation method of a kind of capacitive deionization porous carbon nanofiber according to claim 8, is characterized in that: described current collector is titanium net, titanium sheet, graphite sheet, conductive graphite paper, stainless steel sheet, copper sheet 1. One or more of conductive carbon cloth; the inert conductive plate is one or more of titanium sheet, graphite sheet, conductive graphite paper, stainless steel sheet, and copper sheet. 10. A method for preparing porous carbon nanofibers for capacitive deionization according to claim 8, characterized in that: the capacitor is applied to a salt water desalination system; wherein, the salt water desalination system includes a water storage tank, an intelligent control constant Flow pumps, capacitors, DC power supplies, system controls, conductivity meters, concentration pools.