Resourceful treatment method and system for high-sulfate organic wastewater

Abstract

The invention discloses a high-sulfate organic wastewater resourceful treatment method and system, and relates to the technical field of wastewater treatment. The method comprises the following steps: carrying out bipolar membrane separation treatment on the high-sulfate organic wastewater to obtain dilute alkali, dilute acid and dilute brine; carrying out evaporation and concentration treatment on the dilute alkali to obtain liquid alkali and condensed water; carrying out electrocatalytic oxidation treatment on the dilute brine to obtain electrocatalytic oxidation produced water; performing DTRO concentration on the electrocatalytic oxidation produced water to obtain DTRO produced water and DTRO concentrated water; the dilute acid and the DTRO concentrated water are subjected to photoelectrolysis treatment, and hydrogen and anolyte are obtained; performing crystallization separation on the anolyte to obtain mirabilite and sodium persulfate products; dTRO produced water is used for carrying out crystal dissolving treatment on mirabilite to obtain a saturated or near-saturated sodium sulfate solution, and the saturated or near-saturated sodium sulfate solution is returned to the photoelectrolysis step for circular treatment. According to the method, sulfate in the wastewater is converted into high-value sodium persulfate, the problem that a large amount of industrial by-product sodium sulfate is difficult to digest is avoided, meanwhile, liquid caustic soda, dilute acid, produced water, condensate water and hydrogen can be obtained and can be recycled, and resource utilization of the high-sulfate wastewater is achieved.

Description

Technical Field

[0001] The present application relates to the technical field of wastewater treatment, and in particular to a method and system for resource-based treatment of high-sulfate organic wastewater. Background Art

[0002] In the zero-discharge treatment process of coal chemical concentrated brine, nanofiltration is generally used for salt separation and then evaporation and crystallization to obtain sodium sulfate and sodium chloride products, ultimately achieving zero discharge. However, in the actual operation process, the concentrated water produced by nanofiltration has high sulfate and organic matter content, which belongs to high-sulfate organic wastewater. The sulfate ion content in the wastewater can be as high as 80,000-120,000 mg / L, and the COD content is usually as high as 300-2000 mg / L. It is a typical high-concentration difficult-to-degrade organic wastewater. At present, the "advanced oxidation + evaporation crystallization" process is mainly used for treatment. However, in the case of high salt (total dissolved solids ≥50,000 mg / L), anions in the water (such as Cl - 、SO4 2- , HCO 3- The hydroxyl radicals (such as sodium sulfate, etc.) are easily quenched by the free radicals produced during the catalytic oxidation process, resulting in a significant decrease in the oxidation treatment efficiency. The COD removal rate is generally only about 20-40%, and the concentration of organic matter in the oxidized effluent is still high, which in turn affects the quality of the final by-product salt. It is generally difficult to meet the standard requirements of Class II first-class products of "Industrial Anhydrous Sodium Sulfate" (GB / T 6009-2014). Even if it can meet the requirements of this standard, its recovery rate is low and the amount of impurities is large, that is, the output of hazardous waste is large and the treatment cost is high. Based on this, the present application proposes a method and system for resource treatment of high-sulfate organic wastewater. Summary of the invention

[0003] The main purpose of this application is to provide a method and system for resource treatment of high-sulfate organic wastewater, aiming to solve the technical problem that existing methods are difficult to achieve in the treatment and recycling of high-sulfate organic wastewater.

[0004] To achieve the above purpose, the present application proposes a method for resource treatment of high-sulfate organic wastewater, comprising the following steps:

[0005] The high-sulfate organic wastewater is subjected to bipolar membrane separation treatment to obtain dilute alkali, dilute acid and dilute brine;

[0006] The diluted alkali is evaporated and concentrated to obtain liquid alkali and condensed water;

[0007] The diluted salt water is subjected to electrocatalytic oxidation treatment to obtain electrocatalytic oxidation produced water;

[0008] The electrocatalytic oxidation produced water is subjected to DTRO concentration to obtain DTRO produced water and DTRO concentrated water;

[0009] Performing photoelectrolysis on the dilute acid and the DTRO concentrated water to obtain hydrogen and anolyte;

[0010] Performing crystallization separation on the anolyte to obtain sodium sulfate and sodium persulfate products;

[0011] The DTRO produced water is used to dissolve the mirabilite to obtain a saturated or nearly saturated sodium sulfate solution, which is then returned to the photoelectrolysis treatment step for circulation.

[0012] Optionally, the step of subjecting the high-sulfate organic wastewater to bipolar membrane separation treatment to obtain dilute alkali, dilute acid and dilute brine comprises:

[0013] The high sulfate organic wastewater is treated by bipolar membrane separation through a bipolar membrane reactor with an average current density of 400-1000A / m 2 , to obtain dilute alkali, dilute acid and dilute brine;

[0014] Wherein, the concentration of the dilute alkali is 1-2 mol / L, the concentration of the dilute acid is 1-2 mol / L, the TDS concentration in the dilute brine is 20000-40000 mg / L, and the COD concentration is 300-2000 mg / L;

[0015] The volume ratio of the salt chamber, the alkali chamber and the acid chamber in the bipolar membrane reactor is (10.5-11.5): (7.5-8.5): (6.0-7.5).

[0016] Optionally, in the step of evaporating and concentrating the dilute alkali to recover liquid alkali and condensed water, the evaporation operating temperature is 60-100° C., liquid alkali with an effective concentration of 20-30% is recovered, and the steam consumption is 0.4-0.6 t / t (dilute alkali).

[0017] Optionally, in the step of subjecting the dilute brine to electrocatalytic oxidation treatment to obtain electrocatalytic oxidation water production, the anode is a sub-titanium oxide ceramic electrode, a diamond electrode or a titanium-platinum composite electrode, the cathode is a titanium electrode or a stainless steel electrode, and the current density is 300-600A / m 2 , the voltage is 3-12V, the residence time of the electrocatalytic oxidation reaction is 10-60min, and the COD of the electrocatalytic oxidation produced water is below 100mg / L.

[0018] Optionally, the step of subjecting the dilute acid and the DTRO concentrated water to photoelectrolysis to obtain hydrogen and anolyte comprises:

[0019] A portion of the dilute acid accounting for 50-80% by volume is introduced into a photoelectrolysis reactor together with the DTRO concentrated water for photoelectrolysis, and the remaining portion of the dilute acid is recycled, the operating temperature of the photoelectrolysis reactor is 15-55° C., an acid-base regulator is added to the photoelectrolysis reactor, and the operating pH of the cathode chamber is controlled to be ≤3, and the operating pH of the anode chamber is controlled to be 6-8, the dilute acid is in the cathode chamber, the DTRO concentrated water is in the anode chamber, and ultraviolet light is simultaneously applied to the anode chamber; hydrogen is obtained from the cathode chamber, and an anolyte mixed with sodium persulfate and sodium sulfate is obtained from the anode chamber;

[0020] The photoelectrolysis reactor is provided with a diaphragm, the components of which are a composite ceramic material of barium titanate and clay, and the mass ratio of the barium titanate to the clay is 1:(3.5-8.8); the anode of the photoelectrolysis reactor adopts one of a sub-titanium oxide electrode, a diamond electrode or a titanium-platinum electrode with a high oxygen evolution potential; the cathode of the photoelectrolysis reactor adopts a composite electrode with titanium as a substrate and zirconium, tantalum and ruthenium plated on the surface, and the mass ratio of titanium, zirconium, tantalum and ruthenium is (70-90):(2-3):(0.2-0.5):(0.2-0.5), and the hydrogen evolution potential of the cathode of the photoelectrolysis reactor is lower than -0.5V; the wavelength of the ultraviolet light is 185-365nm, and the intensity of the ultraviolet light is 200-500W / m 2 .

[0021] Optionally, in the step of performing crystallization separation on the anolyte to obtain Glauber's salt and sodium persulfate products, the operating temperature of the crystallization separation is -8 to 8°C, and the content of the sodium persulfate product produced by the crystallization separation is 250-350 g / L.

[0022] Optionally, the step of using the DTRO produced water to dissolve the mirabilite comprises:

[0023] The DTRO produced water is used to dissolve the mirabilite to form a saturated or nearly saturated sodium sulfate solution. The mass ratio of the DTRO produced water to the mirabilite is (0.2-0.3):1. The dissolution temperature is controlled at 35-55°C. The dissolution residence time is 0.5-5min. Stirring is performed at the same time, and the stirring speed is 30-120r / min.

[0024] The present application also proposes a high-sulfate organic wastewater resource treatment system, including a bipolar membrane reactor, an electrocatalytic oxidation reactor, a DTRO membrane device, a photoelectrolysis reactor, a crystallization separation device, a dissolution reactor and an evaporator, wherein the dilute alkali output end of the bipolar membrane reactor is connected to the evaporator, the dilute brine output end of the bipolar membrane reactor is connected to the electrocatalytic oxidation reactor, the water production end of the electrocatalytic oxidation reactor is connected to the DTRO membrane device, the dilute acid output end of the bipolar membrane reactor and the concentrated water end of the DTRO membrane device are connected to the water inlet end of the photoelectrolysis reactor, the cathode side of the photoelectrolysis reactor is provided with a hydrogen outlet end, the anode side of the photoelectrolysis reactor is connected to the crystallization separation device, the water production ends of the crystallization separation device and the DTRO membrane device are both connected to the dissolution reactor, and the dissolution reactor is connected to the water inlet end of the photoelectrolysis reactor.

[0025] Optionally, the photoelectrolytic reactor is provided with electrode plates and diaphragms, the electrode plates include anode mesh plates and cathode mesh plates, the anode mesh plates and the cathode mesh plates are arranged alternately in parallel, there are n anode mesh plates, and there are n+1 cathode mesh plates, the diaphragm is located between the anode mesh plate and the cathode mesh plate, there are 2n diaphragms, water holes are evenly opened on the electrode plates, ultraviolet lamps are provided at the bottom and top of the photoelectrolytic reactor, and the ultraviolet lamps are distributed vertically to the electrode plates.

[0026] Optionally, the crystallization separation device includes a freezing reactor, a compressor, a condenser and a centrifuge, the photoelectrolysis reactor is connected to the water inlet end of the freezing reactor, a heat exchanger is provided in the freezing reactor, the condenser, the heat exchanger and the compressor are connected in sequence, the compressor is connected to the condenser, the outlet end of the freezing reactor is connected to the centrifuge, a centrifugal feed pump is provided between the freezing reactor and the centrifuge, and the solid outlet end of the centrifuge is connected to the crystallization reactor.

[0027] This application includes at least the following beneficial effects:

[0028] The present application firstly separates the high-sulfate organic wastewater by bipolar membrane to obtain dilute alkali, dilute acid and dilute brine respectively. The dilute alkali is evaporated and concentrated to obtain liquid alkali, which can be utilized as a resource, and the generated condensed water can be reused. After the dilute brine is separated by bipolar membrane, its sulfate content is greatly reduced, and TDS can be reduced to below 50000 mg / L. At this time, the dilute brine is electrocatalytically oxidized. Since the anion concentration in the water is relatively low, the quenching reaction of hydroxyl radicals will be significantly weakened, and the corresponding oxidation efficiency will be greatly improved, so that the oxidation of organic matter is more thorough. Compared with the prior art that directly oxidizes the high-sulfate wastewater and then evaporates it, the oxidation efficiency of the present application can be increased by more than 40-50%, so that the quality of the final salt product is not affected by organic matter The electrocatalytic oxidation water is concentrated by DTRO to further recover the salt water resources, and then the sodium sulfate and the dilute acid in the DTRO concentrated water are subjected to photoelectrolysis reaction. The sodium sulfate is discharged at the anode to generate sodium persulfate, and the sulfuric acid reacts at the cathode to obtain electrons to generate hydrogen, and a mixed solution of sodium persulfate and sodium sulfate is obtained on the anode side. The residual sodium sulfate is then crystallized and separated to obtain a 250-350 g / L sodium persulfate solution, and a by-product, sodium sulfate (sodium sulfate decahydrate), is obtained at the same time. In order to avoid the problem of the output of the sodium sulfate having no market, the present application further dissolves the sodium salt and directly uses a part of the DTRO produced water for supplementation to form a saturated or nearly saturated sodium sulfate solution before performing photoelectrolysis treatment to improve the recovery rate of the sodium persulfate product. The present application converts sulfate in wastewater into high-value sodium persulfate, which not only avoids the problem of large amount of industrial by-product sodium sulfate being difficult to digest during oxidation and evaporation in the existing coal chemical concentrated brine zero-discharge process, but also the recovered sodium persulfate has high added value, which can offset part of the treatment cost of high-sulfate wastewater, and has considerable economic benefits. In addition to sodium persulfate, liquid alkali, dilute acid, produced water, condensed water and hydrogen can also be obtained, which can all be recycled, thereby realizing the resource utilization of high-sulfate wastewater.

[0029] The system of the present application includes a bipolar membrane reactor, an electrocatalytic oxidation reactor, a DTRO membrane device, a photoelectrolysis reactor, a crystallization separation device, a dissolution reactor and an evaporator. High-sulfate organic wastewater first enters the bipolar membrane reactor for bipolar membrane separation to achieve acid and alkali resource recovery. The dilute alkali output end of the bipolar membrane reactor is connected to the evaporator, and liquid alkali is obtained after concentration by the evaporator, thereby recovering the liquid alkali. At the same time, the dilute brine produced by the bipolar membrane reactor is oxidized and removed by the electrocatalytic oxidation reactor, and the produced water is then concentrated by the DTRO membrane device. The DTRO Part of the produced water meets the standards and is reused, and the other part is used for sodium sulfate dissolution. The DTRO concentrated water and the dilute acid produced by the bipolar membrane reactor are electrolyzed by the photoelectrolysis reactor to generate a mixed liquid containing sodium persulfate and hydrogen. The mixed liquid is separated by a crystallization separation device to obtain sodium persulfate. At the same time, the separated by-product sodium sulfate decahydrate is washed and dissolved in a crystal dissolution reactor to obtain a saturated or nearly saturated sodium sulfate solution. The sodium sulfate is then returned to the photoelectrolysis reactor for cyclic treatment. After the high-sulfate organic wastewater is treated by this system, high-value sodium persulfate and liquid alkali can be recovered, realizing resource utilization. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] In order to more clearly illustrate the embodiments of the present application 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 application. For ordinary technicians in this field, other drawings can be obtained based on the structures shown in these drawings without paying any creative work.

[0031] Figure 1 This is a schematic diagram of the process of the method for resource treatment of high-sulfate organic wastewater described in the embodiment of the present application;

[0032] Figure 2 This is a schematic diagram of the structure of the high-sulfate organic wastewater resource treatment system described in the embodiment of the present application;

[0033] Figure 3 It is a front view of the photoelectrolysis reactor described in the embodiment of the present application;

[0034] Figure 4 A top view of the photoelectrolysis reactor described in an embodiment of the present application;

[0035] Figure 5 This is a left view of the photoelectrolysis reactor described in an embodiment of the present application.

[0036] Reference numerals:

[0037] 1-bipolar membrane reactor; 101-anion membrane; 102-cation membrane; 103-bipolar membrane; 2-electrocatalytic oxidation reactor; 201-water outlet area; 3-water tank; 4-DTRO membrane device; 5-photoelectrolysis reactor; 501-ultraviolet lamp; 502-electrode plate; 503-water hole; 504-anode mesh plate; 505-cathode mesh plate; 506-diaphragm; 6-crystallization separation device; 601-heat exchanger; 602-freezing reactor; 603-compressor; 604-condenser; 605-centrifugal feed pump; 606-centrifuge; 7-dissolution crystal reactor; 701-heating tube; 702-agitator; 8-evaporator; 9-water inlet pump; 10-boosting pump; 11-hot solution delivery pump.

[0038] The realization of the purpose, functional features and advantages of this application will be further explained in conjunction with embodiments and with reference to the accompanying drawings. DETAILED DESCRIPTION

[0039] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0040] Industrial sodium persulfate can be used as a bleaching agent, oxidant, textile desizing agent, sulfur dye colorant, oil well fracturing fluid breaker, organic polymer emulsion polymerization initiator, waste liquid treatment agent, metal surface treatment agent and printed circuit board etchant. The current market price of sodium persulfate is 5,000-6,000 yuan / ton, which is of high value. If the high sulfate in the wastewater can be converted into sodium persulfate, it will not only solve the environmental problem, but also have significant economic benefits.

[0041] In view of the technical problems existing in the above-mentioned prior art, the embodiments of the present application provide a method for resource-based treatment of high-sulfate organic wastewater, such as Figure 1 As shown, the following steps are included:

[0042] The high-sulfate organic wastewater is subjected to bipolar membrane separation treatment to obtain dilute alkali, dilute acid and dilute brine;

[0043] The diluted alkali is evaporated and concentrated to obtain liquid alkali and condensed water;

[0044] The diluted salt water is subjected to electrocatalytic oxidation treatment to obtain electrocatalytic oxidation produced water;

[0045] The electrocatalytic oxidation produced water is subjected to DTRO concentration to obtain DTRO produced water and DTRO concentrated water;

[0046] Performing photoelectrolysis on the dilute acid and the DTRO concentrated water to obtain hydrogen and anolyte;

[0047] Performing crystallization separation on the anolyte to obtain sodium sulfate and sodium persulfate products;

[0048] The DTRO produced water is used to dissolve the mirabilite to obtain a saturated or nearly saturated sodium sulfate solution, which is then returned to the photoelectrolysis treatment step for circulation.

[0049] The present application firstly separates the high-sulfate organic wastewater by bipolar membrane to obtain dilute alkali, dilute acid and dilute brine respectively. The dilute alkali is evaporated and concentrated to obtain liquid alkali, which can be utilized as a resource, and the generated condensed water can be reused. After the dilute brine is separated by bipolar membrane, its sulfate content is greatly reduced, and TDS can be reduced to below 50000 mg / L. At this time, the dilute brine is electrocatalytically oxidized. Since the anion concentration in the water is relatively low, the quenching reaction of hydroxyl radicals will be significantly weakened, and the corresponding oxidation efficiency will be greatly improved, so that the oxidation of organic matter is more thorough. Compared with the prior art that directly oxidizes the high-sulfate wastewater and then evaporates it, the oxidation efficiency of the present application can be increased by more than 40-50%, so that the quality of the final salt product is not affected. The influence of organic matter can be eliminated by DTRO concentration of electrocatalytic oxidation water to further recover salt water resources, and then the sodium sulfate and dilute acid in the DTRO concentrated water are subjected to photoelectrolysis reaction. Sodium sulfate discharges at the anode to generate sodium persulfate, and sulfuric acid reacts at the cathode to obtain electrons to generate hydrogen. A mixed solution of sodium persulfate and sodium sulfate is obtained on the anode side. The residual sodium sulfate is then crystallized and separated to obtain a sodium persulfate solution, and a by-product, sodium sulfate (sodium sulfate decahydrate), is obtained at the same time. In order to avoid the problem of no market for the produced sodium sulfate, the present application further dissolves the sodium sulfate and directly uses a part of the DTRO produced water for supplementation to form a saturated or nearly saturated sodium sulfate solution before performing photoelectrolysis treatment to improve the recovery rate of the sodium persulfate product. The present application converts sulfate in wastewater into high-value sodium persulfate, which not only avoids the problem of large amount of industrial by-product sodium sulfate being difficult to digest during oxidation and evaporation in the existing coal chemical concentrated brine zero-discharge process, but also the recovered sodium persulfate has high added value, which can offset a part of the treatment cost of high-sulfate wastewater, and has considerable economic benefits. In addition to sodium persulfate, liquid alkali, produced water, condensed water and hydrogen can also be obtained, which can all be recycled, thereby realizing the resource utilization of high-sulfate wastewater.

[0050] As an implementation method of the present application, the step of subjecting the high-sulfate organic wastewater to bipolar membrane separation treatment to obtain dilute alkali, dilute acid and dilute brine comprises:

[0051] The high sulfate organic wastewater is treated by bipolar membrane separation through a bipolar membrane reactor with an average current density of 400-1000A / m 2, to obtain dilute alkali, dilute acid and dilute brine;

[0052] Wherein, the concentration of the dilute alkali is 1-2 mol / L, the concentration of the dilute acid is 1-2 mol / L, the TDS concentration in the dilute brine is 20000-40000 mg / L, and the COD concentration is 300-2000 mg / L;

[0053] The volume ratio of the salt chamber, the alkali chamber and the acid chamber in the bipolar membrane reactor is (10.5-11.5): (7.5-8.5): (6.0-7.5).

[0054] By converting high-sulfate organic wastewater into dilute brine through a bipolar membrane reactor, the sulfate content can be greatly reduced, and the TDS can be reduced to below 50,000 mg / L, so that the subsequent electrocatalytic oxidation of the dilute brine can be facilitated, thereby greatly improving the oxidation efficiency and realizing the recovery of acid and alkali.

[0055] As an implementable method of the present application, in the step of evaporating and concentrating the dilute alkali to recover liquid alkali and condensed water, the evaporation operating temperature is 60-100°C, liquid alkali with an effective concentration of 20-30% is recovered, and the steam consumption is 0.4-0.6t / t (dilute alkali).

[0056] As an implementation method of the present application, in the step of subjecting the dilute brine to electrocatalytic oxidation treatment to obtain electrocatalytic oxidation water production, the anode uses one of a sub-titanium oxide ceramic electrode, a diamond electrode or a titanium-platinum composite electrode, the cathode uses a titanium electrode or a stainless steel electrode, and the current density is 300-600A / m 2 , the voltage is 3-12V, the residence time of the electrocatalytic oxidation reaction is 10-60min, and the COD of the electrocatalytic oxidation produced water is below 100mg / L.

[0057] Specifically, the anode uses a sub-titanium oxide ceramic electrode, a diamond electrode or a titanium-platinum composite electrode, which can efficiently remove organic matter and ammonia nitrogen. The cathode uses a titanium electrode or a stainless steel electrode, which has good corrosion resistance. In the electrocatalytic oxidation process, under the action of an external enhanced current, a potential difference is formed between the anode and the cathode, which can promote the migration or transfer of ions in the solution in the electrolyte, forming a strong electrochemical reaction, converting water into hydroxyl free radicals and oxidizing organic matter, while converting Cl - Converted to ClO - , HClO and other substances to oxidize ammonia nitrogen, thereby significantly reducing the organic matter and ammonia nitrogen in the dilute brine.

[0058] As an implementation method of the present application, in the step of subjecting the electrocatalytic oxidation produced water to DTRO concentration to obtain DTRO produced water and DTRO concentrated water, a desalination membrane is used for DTRO concentration, the operating pressure is 40-90 bar, and the recovery rate is 70-85%.

[0059] Specifically, DTRO (disc tube reverse osmosis) technology is a membrane separation technology that uses the selective permeability of the membrane to separate water molecules from the solution. It is mainly based on the selective permeability of the semipermeable membrane. Under high pressure, water molecules can pass through the semipermeable membrane into the membrane, while solutes are retained outside the membrane. The desalination membrane has a high desalination rate, anti-pollution, corrosion resistance and high efficiency and stability. After DTRO concentration of electrocatalytic oxidation water, it can effectively improve the recovery rate of salt in electrocatalytic oxidation water, has strong anti-pollution ability, more stable system operation, and better economic benefits.

[0060] As an implementable embodiment of the present application, the step of subjecting the dilute acid and the DTRO concentrated water to photoelectrolysis to obtain hydrogen and anolyte includes:

[0061] A portion of the dilute acid accounting for 50-80% by volume is introduced into a photoelectrolysis reactor together with the DTRO concentrated water for photoelectrolysis, and the remaining portion of the dilute acid is recycled, the operating temperature of the photoelectrolysis reactor is 15-55° C., an acid-base regulator is added to the photoelectrolysis reactor, and the operating pH of the cathode chamber is controlled to be ≤3, and the operating pH of the anode chamber is controlled to be 6-8, the dilute acid is in the cathode chamber, the DTRO concentrated water is in the anode chamber, and ultraviolet light is simultaneously applied to the anode chamber; hydrogen is obtained from the cathode chamber, and an anolyte mixed with sodium persulfate and sodium sulfate is obtained from the anode chamber;

[0062] The photoelectrolysis reactor is provided with a diaphragm, the components of which are a composite ceramic material of barium titanate and clay, and the mass ratio of the barium titanate to the clay is 1:(3.5-8.8); the anode of the photoelectrolysis reactor adopts one of a sub-titanium oxide electrode, a diamond electrode or a titanium-platinum electrode with a high oxygen evolution potential; the cathode of the photoelectrolysis reactor adopts a composite electrode with titanium as a substrate and zirconium, tantalum and ruthenium plated on the surface, and the mass ratio of titanium, zirconium, tantalum and ruthenium is (70-90):(2-3):(0.2-0.5):(0.2-0.5), and the hydrogen evolution potential of the cathode of the photoelectrolysis reactor is lower than -0.5V; the wavelength of the ultraviolet light is 185-365nm, and the intensity of the ultraviolet light is 200-500W / m 2 .

[0063] Since the existing technology of electrolyzing Na2SO4 to produce Na2S2O8 has low current efficiency, the efficiency of producing Na2S2O8 is low, and since the solubility difference between Na2S2O8 and Na2SO4 is small in the electrolysis system of Na2S2O8-Na2SO4-H2SO4-H2O, it is very difficult to extract Na2S2O8 from the electrolyte. Therefore, the anode of this application adopts titanium oxide, diamond electrode or titanium-platinum electrode with high oxygen evolution potential to inhibit the generation of oxygen as a byproduct of the anode, so that the anode mainly produces SO4 2- Converted to S2O8 2- At the same time, by adding ultraviolet light to promote SO4 2- Electrolysis is converted into persulfate to improve the efficiency of persulfate production. By setting a diaphragm in the photoelectrolysis reactor, the diaphragm allows hydrogen to pass through while blocking the ions in the water, thus avoiding the S2O8 produced at the anode. 2- It migrates to the cathode and is reduced and consumed, and then a mixed solution of Na2S2O8 and Na2SO4 is obtained on the anode side. After freezing and crystallization, sodium sulfate Na2SO4·10H2O is precipitated to obtain high-purity sodium supersulfate. The cathode adopts a composite metal material with titanium as the base and zirconium, tantalum and ruthenium plated on the surface, and the hydrogen evolution potential is lower than -0.5V, which can effectively promote the production of hydrogen and avoid cathode corrosion.

[0064] Specifically, Na2SO4 discharges at the anode to generate Na2S2O8, and H2SO4 reacts at the cathode to obtain electrons to generate H2. The reaction equation is:

[0065] Anode reaction: 2SO4 2- →S2O8 2- +2e - ;

[0066] Cathode reaction: 2H + +2e - →H2↑.

[0067] As an implementable method of the present application, in the step of crystallizing and separating the anolyte to obtain mirabilite and sodium persulfate products, the operating temperature of the crystallization separation is -8 to 8°C, and the content of the sodium persulfate product produced by the crystallization separation is 250-350g / L.

[0068] Specifically, crystallization separation utilizes the principle that the solubility of sodium sulfate drops sharply under low temperature conditions, and a large amount of Glauber's salt is precipitated from the water. At this time, sodium persulfate is not greatly affected by the temperature drop and will continue to exist in the water in a dissolved state, thereby separating sodium persulfate and sodium sulfate. Sodium persulfate has a high economic value and can be used as a raw material for the preparation of industrial sodium persulfate for resource utilization. After the Glauber's salt dissolves and crystallizes, it returns to the system to continue photoelectrolysis to produce sodium persulfate, thereby improving the recovery rate of sodium persulfate.

[0069] As an implementable method of the present application, the step of dissolving the mirabilite using the DTRO produced water comprises:

[0070] The DTRO produced water is used to dissolve the mirabilite to form a saturated or nearly saturated sodium sulfate solution. The mass ratio of the DTRO produced water to the mirabilite is (0.2-0.3):1. The dissolution temperature is controlled at 35-55°C. The dissolution residence time is 0.5-5min. Stirring is performed at the same time, and the stirring speed is 30-120r / min.

[0071] Specifically, the Glauber's salt produced by crystallization needs to undergo crystal dissolution to form a saturated or nearly saturated sodium sulfate solution, and finally return to the photoelectrolysis step for circulation treatment to avoid the problem of the final output of Glauber's salt having no market, and can improve the recovery rate of the sodium persulfate product. Since water needs to be added to dissolve the Glauber's salt during the crystal dissolution process, this part of the added water can be directly supplemented with DTRO produced water, thereby realizing the recycling of DTRO produced water within the system.

[0072] An embodiment of the present application also provides a high-sulfate organic wastewater resource treatment system, comprising a bipolar membrane reactor 1, an electrocatalytic oxidation reactor 2, a DTRO membrane device 4, a photoelectrolysis reactor 5, a crystallization separation device 6, a dissolution reactor 7 and an evaporator 8, wherein the dilute alkali output end of the bipolar membrane reactor 1 is connected to the evaporator 8, the dilute brine output end of the bipolar membrane reactor 1 is connected to the electrocatalytic oxidation reactor 2, the water production end of the electrocatalytic oxidation reactor 2 is connected to the DTRO membrane device 4, the dilute acid output end of the bipolar membrane reactor 1 and the concentrated water end of the DTRO membrane device 4 are connected to the water inlet end of the photoelectrolysis reactor 5, the cathode side of the photoelectrolysis reactor 5 is provided with a hydrogen outlet end, the anode side of the photoelectrolysis reactor 5 is connected to the crystallization separation device 6, the water production ends of the crystallization separation device 6 and the DTRO membrane device 4 are both connected to the dissolution reactor 7, and the dissolution reactor 7 is connected to the water inlet end of the photoelectrolysis reactor 5.

[0073] The high-sulfate organic wastewater resource treatment system of the present application includes a bipolar membrane reactor 1, an electrocatalytic oxidation reactor 2, a DTRO membrane device 4, a photoelectrolysis reactor 5, a crystallization separation device 6, a dissolution reactor 7 and an evaporator 8. The high-sulfate organic wastewater first enters the bipolar membrane reactor 1 for membrane separation to achieve resource recovery of acid and alkali. The dilute alkali output end of the bipolar membrane reactor 1 is connected to the evaporator 8, and liquid alkali is obtained after concentration by the evaporator 8, thereby recovering the liquid alkali. At the same time, the dilute brine produced by the bipolar membrane reactor 1 is oxidized and removed by the electrocatalytic oxidation reactor 2, and the produced water is then passed through the DTRO membrane The device 4 is concentrated, and part of the DTRO produced water meets the standards and is reused, and the other part of the produced water is used for sodium sulfate dissolution. The DTRO concentrated water and the dilute acid produced by the bipolar membrane reactor 1 are electrolyzed by the photoelectrolysis reactor 5 to generate a mixed solution containing sodium persulfate and hydrogen. The mixed solution is separated by the crystallization separation device 6 to obtain sodium persulfate. At the same time, the separated by-product sodium sulfate decahydrate is washed and dissolved by the crystal dissolution reactor 7 to obtain a saturated or nearly saturated sodium sulfate solution. The sodium sulfate is then returned to the photoelectrolysis reactor 5 for cyclic treatment. After the high-sulfate organic wastewater is treated by this system, high-value sodium persulfate and liquid alkali can be recovered, thereby realizing resource utilization.

[0074] As an implementation method of the present application, the bipolar membrane reactor 1 includes a cationic membrane 101, a cation membrane 102 and at least one group of bipolar membranes 103. The cationic membrane 101, the cation membrane 102 and the bipolar membrane 103 are connected by a positioning flexible connection method, and the cationic membrane 101 and the cation membrane 102 are homogeneous membranes.

[0075] As an implementation method of the present application, a water outlet area 201 is provided in the electrocatalytic oxidation reactor 2, and a water tank 3 is provided between the electrocatalytic oxidation reactor 2 and the DTRO membrane device 4. The water outlet area 201 is connected to the water tank 3, and the produced water treated by the electrocatalytic oxidation reactor 2 enters the water tank 3 through the water outlet area 201 and is stored.

[0076] As an implementation method of the present application, a tubular electrode or a plate electrode is provided in the reaction zone of the electrocatalytic oxidation reactor 2. The tubular electrode is a hollow cylindrical electrode assembly with coaxial positive and negative electrodes, and the plate electrode is a parallel plate electrode with positive and negative electrodes arranged alternately.

[0077] As an embodiment of the present application, the photoelectrolytic reactor 5 is provided with an electrode plate 502 and a diaphragm 506, the electrode plate 502 includes an anode mesh plate 504 and a cathode mesh plate 505, the anode mesh plate 504 and the cathode mesh plate 505 are arranged alternately in parallel, the anode mesh plate 504 is provided with n pieces, the cathode mesh plate 505 is provided with n+1 pieces, the diaphragm 506 is located between the anode mesh plate 504 and the cathode mesh plate 505, the diaphragm 506 is provided with 2n pieces, the electrode plate 502 is evenly provided with water holes 503, the bottom and top of the photoelectrolytic reactor 5 are provided with ultraviolet lamps, and the ultraviolet lamps 501 are vertically distributed with the electrode plates 502.

[0078] Specifically, the water hole 503 has a diameter of 2-4 mm and a porosity of 20-30%, which facilitates smooth water flow and improves mass transfer efficiency. The center distance between the bottom ultraviolet lamp 501 and the top ultraviolet lamp 501 is 300-800 mm. The ultraviolet lamp 501 is a plurality of tubular lamps arranged in parallel, and a waterproof quartz glass sleeve is arranged outside the lamp.

[0079] As an implementation method of the present application, the crystallization separation device 6 includes a freezing reactor 602, a compressor 603, a condenser 604 and a centrifuge 606. The photoelectrolysis reactor 5 is connected to the water inlet end of the freezing reactor 602. A heat exchanger 601 is provided in the freezing reactor 602. The condenser 604, the heat exchanger 601 and the compressor 603 are connected in sequence. The compressor 603 is connected to the condenser 604. The outlet end of the freezing reactor 602 is connected to the centrifuge 606. A centrifugal feed pump 606 is provided between the freezing reactor 602 and the centrifuge 606. The solid outlet end of the centrifuge 606 is connected to the dissolution crystal reactor 7.

[0080] Specifically, the crystallization separation process is to exchange heat with the anode liquid through the heat exchanger 601, and then compress it through the compressor 603 and condense it through the condenser 604 to reduce the temperature to between -8 and 8°C, so that the sodium sulfate in the anode liquid is crystallized to obtain Glauber's salt, and then the Glauber's salt is separated through the centrifuge 606. The filtrate after separation is high-purity sodium sulfate.

[0081] As an implementation method of the present application, a heating tube 701 and an agitator 702 are provided in the crystal dissolution reactor 7. In order to enable the Glauber's salt crystals to quickly dissolve into a saturated or nearly saturated sodium sulfate solution, heating is performed by the heating tube 701 while stirring is performed by the agitator 702, thereby increasing the dissolution rate of the Glauber's salt.

[0082] The above technical solution of the present application is described in detail below in conjunction with specific embodiments.

[0083] Example 1

[0084] A method for resource treatment of high-sulfate organic wastewater comprises the following steps:

[0085] The high sulfate organic wastewater is pumped into the bipolar membrane reactor 1 through the water inlet pump 9 for membrane separation treatment, and the average current density is 700A / m 2 , 1.5mol / L of dilute alkali, 1.5mol / L of dilute acid and dilute brine were obtained; the TDS concentration in the dilute brine was 28342mg / L, and the COD concentration was 1125mg / L;

[0086] The volume ratio of the salt chamber, the alkali chamber and the acid chamber in the bipolar membrane reactor 1 is 11:8:6.7;

[0087] The diluted alkali is passed from the alkali chamber into the evaporator 8 for evaporation and concentration treatment, the evaporation operating temperature is 80°C, the steam consumption is 0.5t / t (dilute alkali), and liquid alkali with an effective concentration of 25% and condensed water are recovered, and the condensed water is reused;

[0088] The dilute brine is passed from the salt chamber into the electrocatalytic oxidation reactor 2 for electrocatalytic oxidation treatment. The anode is a sub-titanium oxide ceramic electrode, the cathode is a titanium electrode, and the current density is 450A / m 2 , the voltage is 7V, the residence time of the electrocatalytic oxidation reaction is 35min, the COD of the electrocatalytic oxidation water is 85mg / L, and the electrocatalytic oxidation water is obtained;

[0089] The electrocatalytic oxidation produced water is stored in a water tank 3, and then passed into a DTRO membrane device 4 through a booster pump 10 for DTRO concentration. The DTRO concentration is carried out using a desalination membrane, the operating pressure is 65 bar, and the recovery rate is 77%, thereby obtaining DTRO produced water and DTRO concentrated water;

[0090] Half of the dilute acid is recycled, and the other half is passed from the acid chamber into the photoelectrolysis reactor 5, and the DTRO concentrated water is passed into the photoelectrolysis reactor 5, the operating temperature of the photoelectrolysis reaction is 35°C, an acid-base regulator is added to the photoelectrolysis reactor 5, the operating pH of the cathode chamber is controlled to be ≤3, and the operating pH of the anode chamber is controlled to be 7.2, the dilute acid is in the cathode chamber, and the DTRO concentrated water is in the anode chamber, and ultraviolet light is simultaneously applied in the anode chamber to perform electrolysis, hydrogen is collected from the cathode chamber, and an anolyte mixed with sodium persulfate and sodium sulfate is collected from the anode chamber;

[0091] A diaphragm 506 is provided in the photoelectrolysis reactor 5, wherein the diaphragm 506 is composed of a composite ceramic material of barium titanate and clay, wherein the mass ratio of barium titanate to clay is 1:6.3; the anode of the photoelectrolysis reactor 5 adopts a sub-titanium oxide electrode having a high oxygen evolution potential; the cathode of the photoelectrolysis reactor 5 adopts a composite electrode having a titanium substrate and a surface coated with zirconium, tantalum and ruthenium, wherein the mass ratio of titanium, zirconium, tantalum and ruthenium is 80:2.5:0.3:0.35, and the hydrogen evolution potential of the cathode of the photoelectrolysis reactor 5 is lower than -0.5V;

[0092] The anolyte is passed into the crystallization separation device 6, and the temperature is lowered to 0°C to separate the residual sodium sulfate by crystallization, and then sodium sulfate and 300 g / L sodium persulfate are obtained;

[0093] Thenardite is added into the crystal dissolution reactor 7, and thenardite is crystallized by using DTRO produced water to dissolve the thenardite, so that a saturated or nearly saturated sodium sulfate solution is formed after the thenardite is dissolved. The mass ratio of DTRO produced water to thenardite is 0.25:1, the crystal dissolution temperature is controlled at 45°C, the crystal dissolution residence time is 2.5min, and stirring is performed at the same time, and the stirring speed is 75r / min. A saturated or nearly saturated sodium sulfate solution is obtained and pumped into the photoelectrolysis reactor 5 through the hot solution delivery pump 11 for circulation treatment.

[0094] Example 2

[0095] A method for resource treatment of high-sulfate organic wastewater comprises the following steps:

[0096] The high sulfate organic wastewater is pumped into the bipolar membrane reactor 1 through the water inlet pump 9 for bipolar membrane separation treatment, and the average current density is 1000A / m 2 , 2mol / L of dilute alkali, 2mol / L of dilute acid and dilute brine were obtained; the TDS concentration in the dilute brine was 20134mg / L, and the COD concentration was 317mg / L;

[0097] The volume ratio of the salt chamber, the alkali chamber and the acid chamber in the bipolar membrane reactor 1 is 10.5:7.5:6.2;

[0098] The diluted alkali is passed from the alkali chamber into the evaporator 8 for evaporation and concentration treatment, the evaporation operating temperature is 100°C, the steam consumption is 0.4t / t (dilute alkali), and liquid alkali with an effective concentration of 20% and condensed water are recovered, and the condensed water is reused;

[0099] The dilute brine is passed from the salt chamber into the electrocatalytic oxidation reactor 2 for electrocatalytic oxidation treatment. The anode is a sub-titanium oxide ceramic electrode, a diamond electrode or a titanium-platinum composite electrode, and the cathode is a titanium electrode or a stainless steel electrode. The current density is 600A / m 2The residence time of the electrocatalytic oxidation reaction is 60 minutes, the COD of the electrocatalytic oxidation water is 43 mg / L, and the removal rate is 86.4%, and the electrocatalytic oxidation water is obtained;

[0100] The electrocatalytic oxidation produced water is stored in a water tank 3, and then passed into a DTRO membrane device 4 through a booster pump 10 for DTRO concentration. The DTRO concentration is carried out using a desalination membrane, the operating pressure is 90 bar, and the recovery rate is 85%, thereby obtaining DTRO produced water and DTRO concentrated water;

[0101] A part of the dilute acid is recycled, and the other part is passed from the acid chamber into the photoelectrolysis reactor 5, the volume ratio of the two is 2:8, and the DTRO concentrated water is passed into the photoelectrolysis reactor 5 for photoelectrolysis, the operating temperature of the photoelectrolysis reactor 5 is 15-55°C, an acid-base regulator is added to the photoelectrolysis reactor 5, the operating pH of the cathode chamber is controlled to be ≤3, and the operating pH of the anode chamber is controlled to be 8, the dilute acid is in the cathode chamber, the DTRO concentrated water is in the anode chamber, and ultraviolet light is simultaneously applied in the anode chamber; hydrogen is collected from the cathode chamber, and an anolyte mixed with sodium persulfate and sodium sulfate is collected from the anode chamber;

[0102] A diaphragm 506 is provided in the photoelectrolysis reactor 5, wherein the diaphragm 506 is composed of a composite ceramic material of barium titanate and clay, wherein the mass ratio of barium titanate to clay is 1:8.8; the anode of the photoelectrolysis reactor 5 adopts a titanium-platinum electrode having a high oxygen evolution potential; the cathode of the photoelectrolysis reactor 5 adopts a composite electrode having a titanium substrate and a surface plated with zirconium, tantalum and ruthenium, wherein the mass ratio of titanium, zirconium, tantalum and ruthenium is 90:3:0.5:0.5, and the hydrogen evolution potential of the cathode of the photoelectrolysis reactor 5 is lower than -0.5V;

[0103] The anolyte is passed into the crystallization separation device 6, and the temperature is lowered to -5°C to crystallize and separate the remaining small amount of sodium sulfate, thereby obtaining mirabilite and 350 g / L of sodium persulfate;

[0104] Thenardite is added into the crystal dissolution reactor 7, and thenardite is crystallized by using DTRO produced water to dissolve the thenardite, so that a saturated or nearly saturated sodium sulfate solution is formed after the thenardite is dissolved. The mass ratio of DTRO produced water to thenardite is 0.3:1, the crystal dissolution temperature is controlled at 55°C, the crystal dissolution residence time is 5min, and stirring is performed at the same time, and the stirring speed is 120r / min. A saturated or nearly saturated sodium sulfate solution is obtained and pumped into the photoelectrolysis reactor 5 through a hot solution delivery pump 11 for circulation treatment.

[0105] Comparative Example

[0106] Compared with Example 2, when the dilute brine is passed from the salt chamber into the electrocatalytic oxidation reactor 2 for electrocatalytic oxidation treatment, salt (sodium sulfate) is added to increase the TDS in the water from 20134 mg / L to 60000 mg / L, and the electrocatalytic oxidation reaction is carried out under the same operating conditions as in Example 2, and the remaining steps are the same. The comparative data during the electrocatalytic oxidation reaction are shown in Table 1 below.

[0107] Table 1 Experimental data of electrocatalytic oxidation reaction under different salt contents

[0108]

[0109] As can be seen from Table 1, the COD of the electrocatalytic oxidation effluent in the comparative example is 185 mg / L, and the removal rate is only 41.6%, which means that the higher the influent TDS salt content, the lower the efficiency of electrocatalytic oxidation in removing COD under the same electrocatalytic oxidation reaction conditions. This further illustrates that the higher the salt content, the greater the inhibitory effect on the efficiency of the catalytic oxidation reaction, that is, reducing the salt content in the water can weaken the annihilation effect of hydroxyl radicals in the catalytic oxidation process.

[0110] The above description is only an optional embodiment of the present application, and does not limit the patent scope of the present application. All equivalent structural transformations made by using the contents of the present application specification and drawings under the inventive concept of the present application, or directly / indirectly applied in other related technical fields are included in the patent protection scope of the present application.

Claims

1. A method for resource treatment of high-sulfate organic wastewater, characterized in that: The following steps are involved: The high-sulfate organic wastewater is subjected to bipolar membrane separation treatment to obtain dilute alkali, dilute acid and dilute brine; The diluted alkali is evaporated and concentrated to obtain liquid alkali and condensed water; The diluted salt water is subjected to electrocatalytic oxidation treatment to obtain electrocatalytic oxidation produced water; The electrocatalytic oxidation produced water is subjected to DTRO concentration to obtain DTRO produced water and DTRO concentrated water; Performing photoelectrolysis on the dilute acid and the DTRO concentrated water to obtain hydrogen and anolyte; Performing crystallization separation on the anolyte to obtain sodium sulfate and sodium persulfate products; The DTRO produced water is used to dissolve the mirabilite to obtain a saturated or nearly saturated sodium sulfate solution, which is then returned to the photoelectrolysis treatment step for circulation.

2. The method for resource treatment of high-sulfate organic wastewater according to claim 1, characterized in that: The step of subjecting the high-sulfate organic wastewater to bipolar membrane separation treatment to obtain dilute alkali, dilute acid and dilute brine comprises: The high sulfate organic wastewater is treated by bipolar membrane separation through a bipolar membrane reactor with an average current density of 400-1000A / m 2 , to obtain dilute alkali, dilute acid and dilute brine; Wherein, the concentration of the dilute alkali is 1-2 mol / L, the concentration of the dilute acid is 1-2 mol / L, the TDS concentration in the dilute brine is 20000-40000 mg / L, and the COD concentration is 300-2000 mg / L; The volume ratio of the salt chamber, the alkali chamber and the acid chamber in the bipolar membrane reactor is (10.5-11.5): (7.5-8.5): (6.0-7.5).

3. The method for resource treatment of high-sulfate organic wastewater according to claim 1, characterized in that: In the step of evaporating and concentrating the dilute alkali to recover liquid alkali and condensed water, the evaporation operating temperature is 60-100° C., liquid alkali with an effective concentration of 20-30% is recovered, and the steam consumption is 0.4-0.6 t / t (dilute alkali).

4. The method for resource treatment of high-sulfate organic wastewater according to claim 1, characterized in that: In the step of subjecting the dilute brine to electrocatalytic oxidation treatment to obtain electrocatalytic oxidation water production, the anode is a titanium oxide ceramic electrode, a diamond electrode or a titanium-platinum composite electrode, the cathode is a titanium electrode or a stainless steel electrode, and the current density is 300-600A / m 2 , the voltage is 3-12V, the residence time of the electrocatalytic oxidation reaction is 10-60min, and the COD of the electrocatalytic oxidation produced water is below 100mg / L.

5. The method for resource treatment of high-sulfate organic wastewater according to claim 1, characterized in that: The step of subjecting the dilute acid and the DTRO concentrated water to photoelectrolysis to obtain hydrogen and anolyte comprises: A portion of the dilute acid accounting for 50-80% by volume is introduced into a photoelectrolysis reactor together with the DTRO concentrated water for photoelectrolysis, and the remaining portion of the dilute acid is recycled, the operating temperature of the photoelectrolysis reactor is 15-55° C., an acid-base regulator is added to the photoelectrolysis reactor, and the operating pH of the cathode chamber is controlled to be ≤3, and the operating pH of the anode chamber is controlled to be 6-8, the dilute acid is in the cathode chamber, the DTRO concentrated water is in the anode chamber, and ultraviolet light is simultaneously applied to the anode chamber; hydrogen is obtained from the cathode chamber, and an anolyte mixed with sodium persulfate and sodium sulfate is obtained from the anode chamber; The photoelectrolysis reactor is provided with a diaphragm, the components of which are a composite ceramic material of barium titanate and clay, and the mass ratio of the barium titanate to the clay is 1:(3.5-8.8); the anode of the photoelectrolysis reactor adopts one of a sub-titanium oxide electrode, a diamond electrode or a titanium-platinum electrode with a high oxygen evolution potential; the cathode of the photoelectrolysis reactor adopts a composite electrode with titanium as a substrate and zirconium, tantalum and ruthenium plated on the surface, and the mass ratio of titanium, zirconium, tantalum and ruthenium is (70-90):(2-3):(0.2-0.5):(0.2-0.5), and the hydrogen evolution potential of the cathode of the photoelectrolysis reactor is lower than -0.5V; the wavelength of the ultraviolet light is 185-365nm, and the intensity of the ultraviolet light is 200-500W / m 2 .

6. The method for resource treatment of high-sulfate organic wastewater according to claim 1, characterized in that: In the step of performing crystallization separation on the anolyte to obtain mirabilite and sodium persulfate products, the operating temperature of the crystallization separation is -8 to 8° C., and the content of the sodium persulfate product produced by the crystallization separation is 250-350 g / L.

7. The method for recycling high-sulfate organic wastewater according to claim 1, characterized in that: The step of using the DTRO produced water to dissolve the mirabilite comprises: The DTRO produced water is used to dissolve the mirabilite to form a saturated or nearly saturated sodium sulfate solution. The mass ratio of the DTRO produced water to the mirabilite is (0.2-0.3):

1. The dissolution temperature is controlled at 35-55°C. The dissolution residence time is 0.5-5min. Stirring is performed at the same time, and the stirring speed is 30-120r / min.

8. A high-sulfate organic wastewater resource treatment system, characterized in that: The invention comprises a bipolar membrane reactor, an electrocatalytic oxidation reactor, a DTRO membrane device, a photoelectrolytic reactor, a crystallization separation device, a dissolving crystal reactor and an evaporator. The dilute alkali output end of the bipolar membrane reactor is connected to the evaporator, the dilute brine output end of the bipolar membrane reactor is connected to the electrocatalytic oxidation reactor, the water production end of the electrocatalytic oxidation reactor is connected to the DTRO membrane device, the dilute acid output end of the bipolar membrane reactor and the concentrated water end of the DTRO membrane device are connected to the water inlet end of the photoelectrolytic reactor, the cathode side of the photoelectrolytic reactor is provided with a hydrogen outlet end, the anode side of the photoelectrolytic reactor is connected to the crystallization separation device, the water production ends of the crystallization separation device and the DTRO membrane device are both connected to the dissolving crystal reactor, and the dissolving crystal reactor is connected to the water inlet end of the photoelectrolytic reactor.

9. The high-sulfate organic wastewater resource treatment system according to claim 8, characterized in that: The photoelectrolytic reactor is provided with electrode plates and diaphragms, the electrode plates include anode mesh plates and cathode mesh plates, the anode mesh plates and the cathode mesh plates are arranged alternately in parallel, there are n anode mesh plates, and there are n+1 cathode mesh plates, the diaphragm is located between the anode mesh plates and the cathode mesh plates, there are 2n diaphragms, water holes are evenly opened on the electrode plates, ultraviolet lamps are provided at the bottom and top of the photoelectrolytic reactor, and the ultraviolet lamps are vertically distributed to the electrode plates.

10. The high-sulfate organic wastewater resource treatment system according to claim 8, characterized in that: The crystallization separation device includes a freezing reactor, a compressor, a condenser and a centrifuge. The photoelectrolysis reactor is connected to the water inlet end of the freezing reactor. A heat exchanger is arranged in the freezing reactor. The condenser, the heat exchanger and the compressor are connected in sequence. The compressor is connected to the condenser. The outlet end of the freezing reactor is connected to the centrifuge. A centrifugal feed pump is arranged between the freezing reactor and the centrifuge. The solid outlet end of the centrifuge is connected to the dissolution crystal reactor.

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