CN110627284B - Method for treating salt-containing wastewater by forward osmosis membrane distillation - Google Patents
Method for treating salt-containing wastewater by forward osmosis membrane distillation Download PDFInfo
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- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F1/00—Treatment of water, waste water, or sewage
- C02F1/02—Treatment of water, waste water, or sewage by heating
- C02F1/04—Treatment of water, waste water, or sewage by heating by distillation or evaporation
- C02F1/08—Thin film evaporation
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- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F1/00—Treatment of water, waste water, or sewage
- C02F1/44—Treatment of water, waste water, or sewage by dialysis, osmosis or reverse osmosis
- C02F1/445—Treatment of water, waste water, or sewage by dialysis, osmosis or reverse osmosis by forward osmosis
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- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F2101/00—Nature of the contaminant
- C02F2101/30—Organic compounds
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- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F2103/00—Nature of the water, waste water, sewage or sludge to be treated
- C02F2103/30—Nature of the water, waste water, sewage or sludge to be treated from the textile industry
Abstract
The invention belongs to the field of chemical wastewater treatment, relates to a method for treating salt-containing wastewater, and particularly relates to a method for treating salt-containing wastewater by adopting forward osmosis membrane distillation. The water with high salt concentration generated by membrane distillation is used as the draw solution in forward osmosis, forward osmosis and membrane distillation are combined, water resources and salt are recovered simultaneously, and the regeneration of the draw solution in the forward osmosis process is realized. The method can be used for treating the high-salinity wastewater, so that water resources and salt in the high-salinity wastewater can be recovered simultaneously, and the two processes are carried out simultaneously and mutually promoted. The technical scheme can be applied to the treatment of high-salinity wastewater and the like so as to realize zero pollution emission and resource recycling.
Description
Technical Field
The invention belongs to the field of chemical wastewater treatment, relates to a method for treating high-concentration salt-containing wastewater, and particularly relates to a method for treating salt-containing wastewater by adopting forward osmosis membrane distillation.
Background
The printing and dyeing wastewater is a general term for various wastewater generated by processing fiber materials in printing and dyeing factories, woolen mills, knitting mills and the like, and causes serious environmental pollution. The printing and dyeing wastewater contains a large amount of amino compounds, phenols and other series organic matters, and a large amount of sodium chloride, sodium sulfate and other inorganic salt substances, and even the content of the inorganic salt substances in the printing and dyeing wastewater can reach more than 3.0 w.t%. The waste water has low biodegradability and is difficult to treat, but if a large amount of electrolytes and water resources in the printing and dyeing waste water can be effectively recovered to obtain inorganic salt products and regenerated water, zero pollution emission and resource recycling can be realized.
Forward osmosis refers to a desalination (or salt enrichment) method for spontaneously transferring water by means of osmotic pressure difference, and the method has the advantages of high water yield, high salt enrichment efficiency, no need of external pressure drive, reversible membrane pollution and high salt wastewater treatment. The forward osmosis process is to make water spontaneously permeate from the wastewater into the draw solution, and other solutes are trapped, so as to realize desalination of water and enrichment of salt. However, the application of forward osmosis membranes has not been completely popularized so far, the forward osmosis draw solution is diluted in the working process, the osmotic pressure must be maintained by concentration and recovery, and the regeneration of the draw solution is one of the most difficult problems to solve at present.
Disclosure of Invention
The invention aims to provide a method for treating salt-containing wastewater by adopting forward osmosis membrane distillation, which combines forward osmosis and membrane distillation, simultaneously recovers water resources and salt and realizes the regeneration of an extraction liquid in the forward osmosis process.
In order to solve the technical problems, the technical scheme of the invention is as follows,
the method for treating the salt-containing wastewater by adopting forward osmosis membrane distillation comprises the following steps:
(1) pretreatment: pretreating high-salinity wastewater to obtain water supply, wherein the water supply comprises a membrane distillation water supply part and a forward osmosis water supply part;
(2) membrane distillation and water collection: conveying the membrane distillation water supply into a membrane distillation water supply tank, conveying the membrane distillation water supply into a membrane distillation unit, carrying out membrane distillation on the membrane distillation water supply to obtain concentrated water and recovered water, collecting the recovered water, and conveying the concentrated water back to the membrane distillation water supply tank; when the conductivity of the membrane distillation feed water in the membrane distillation feed water tank is greater than or equal to a set threshold value I, conveying the membrane distillation feed water in the membrane distillation feed water tank to a draw liquid tank to obtain a draw liquid;
(3) forward osmosis: conveying forward osmosis water supply into a forward osmosis water supply tank, conveying the forward osmosis water supply into a stock solution side of a forward osmosis unit, conveying the forward osmosis water supply back to the forward osmosis water supply tank, and circulating forward osmosis water supply between the forward osmosis water supply tank and the forward osmosis unit; conveying the draw solution from the draw solution pool into a draw solution side of the forward osmosis unit, and then conveying the draw solution back to the draw solution pool, wherein the draw solution circularly flows between the draw solution pool and the forward osmosis unit; in the forward osmosis unit, water in forward osmosis feed water enters the draw solution side from the stock solution side through the forward osmosis membrane;
(4) collecting high-salinity water: when the conductivity of the forward osmosis water supply in the forward osmosis water supply tank is greater than or equal to a set threshold value II, collecting the concentrated forward osmosis water supply to obtain high-salt water;
(5) regeneration of the draw solution: and when the conductivity of the draw solution in the draw solution pool is less than or equal to a set threshold value III, conveying part of the draw solution into a membrane distillation water supply pool.
By adopting the technical scheme, the technical principle is as follows: after the high-salinity wastewater is pretreated, the obtained water supply is divided into a membrane distillation water supply part and a forward osmosis water supply part. Inputting membrane distillation feed water into a membrane distillation feed water tank, and obtaining reclaimed water and concentrated water through membrane distillation, wherein the reclaimed water is the water resource reclaimed by the method. And returning the concentrated water to the membrane distillation water supply tank again, continuously increasing the salt ion concentration of the water in the membrane distillation water supply tank until the conductivity of the membrane distillation water supply in the membrane distillation water supply tank is greater than or equal to a set threshold I, and conveying the membrane distillation water supply in the membrane distillation water supply tank into a liquid drawing tank to obtain a drawing liquid. At the same time, the membrane distillation pool is supplemented with membrane distillation feed water which is just pretreated.
The forward osmosis water supply circularly flows between the forward osmosis water supply tank and the forward osmosis unit, the drawing liquid circularly flows between the drawing liquid tank and the forward osmosis unit, in the forward osmosis unit, water in the forward osmosis water supply enters the drawing liquid side from the stock solution side through the forward osmosis membrane, salt ions in the forward osmosis water supply are enriched, and the drawing liquid is diluted. When the conductivity of the forward osmosis water supply in the forward osmosis water supply tank is greater than or equal to a set threshold value II, high salt water can be collected, and is one of the target products of the method, so that the recovery of salt is realized. And when the conductivity of the draw solution in the draw solution pool is less than or equal to a set threshold value III, conveying part of the draw solution into a membrane distillation water supply pool, regenerating the draw solution by utilizing membrane distillation, and recovering the salt ion concentration of the draw solution. When the conductivity of the membrane distillation feed water in the membrane distillation feed water tank is larger than or equal to a set threshold I, the draw solution with high salt ion concentration can be supplemented to the draw solution tank.
In the scheme, the high-salinity wastewater refers to wastewater with the content of inorganic salt substances reaching more than 3.0 w.t%. The printing and dyeing wastewater contains a large amount of organic pollutants and inorganic salt substances, is wastewater generated by processing fiber materials in a printing and dyeing mill, a woolen mill, a knitting mill and the like, and has higher salt ion concentration which can reach more than 3.0 w.t%.
Has the advantages that: forward osmosis has a number of unique advantages over pressure driven membrane separation processes such as reverse osmosis: the operation can be carried out at low pressure or even no pressure, so the energy consumption is lower; the concentration of the draw solution can be artificially controlled, so that higher osmotic driving pressure is obtained, higher water recovery rate and solute concentration rate are achieved, and high-pollution wastewater which cannot be treated by reverse osmosis can be treated; in the forward osmosis process, the forward osmosis membrane has strong pollution resistance, and can greatly reduce the requirement on the quality of inlet water (forward osmosis water supply). The difficult problem of regeneration of the forward osmosis drawing liquid is solved by a membrane distillation technology, and forward osmosis and membrane distillation can be matched to simultaneously concentrate salt-containing wastewater and recover water resources.
In conclusion, the beneficial effects are that:
(1) the method can be used for treating the high-salinity wastewater, so that water resources and salt in the high-salinity wastewater can be recovered simultaneously, and the two processes are carried out simultaneously and mutually promoted.
(2) Solves the problem of regeneration of the drawing liquid in the forward osmosis process, and directly utilizes the concentrated water with high salt concentration generated in the membrane distillation.
(3) The salt in the high-salinity wastewater is concentrated by utilizing the forward osmosis process, the salt concentration can be finished without external pressure driving, and compared with the processes of reverse osmosis, electrodialysis and the like, the method saves energy and has low operation cost.
(4) By adopting the technical scheme, the concentration of the drawing liquid is controlled, the method has better treatment capacity for the wastewater with high pollution and high solute concentration, and is suitable for treating the wastewater with overhigh solute content and incapable of being separated by using a reverse osmosis technology.
(5) The forward osmosis process is a naturally occurring process, relatively light pollution is caused to the forward osmosis membrane, and compared with a reverse osmosis process, the forward osmosis process reduces the cost and time required for membrane regeneration and membrane cleaning and also reduces the requirement on the water quality of sewage to be treated.
Therefore, when high-salinity wastewater is treated, if the energy consumption of the treatment process is expected to be lower, the solute concentration of the high-salinity wastewater is too high, or the water quality of the high-salinity wastewater is too poor, the forward osmosis and membrane distillation combined method in the technical scheme can be selected. The scheme of the invention is particularly suitable for treating the industrial wastewater with the content of the salt substances including the printing and dyeing wastewater being more than 3.0 w.t%.
Further, in the step (1), the method for pretreating the high-salinity wastewater comprises the following steps: adding ferrous sulfate, hydrogen peroxide and nickel oxide modified carbon nano tubes into the high-salinity wastewater to obtain a pretreatment system; stirring the pretreatment system at room temperature for 4h, standing for 5h, and taking supernatant, wherein the supernatant is the water supply.
By adopting the technical scheme, the content of organic matters including organic phosphorus in the high-salinity wastewater can be reduced, and impurities are reduced, so that the forward osmosis efficiency and the membrane distillation efficiency are improved, and the quality of a final product is improved.
The high-salinity wastewater has high concentration of organic matters, in particular organic phosphorus, ammonia nitrogen organic matters and volatile substances, and the organic matters have high toxicity and are difficult to biodegrade. The distillation membrane in the membrane distillation unit is easily wetted by organic components, so that the hydrophobic property is lost, the working efficiency of the distillation membrane is reduced, membrane distillation water supply can directly leak into a recovery side (fresh water) through wetted membrane pores, and the quality of recovered water is reduced. Small molecule organic compounds, dissolved gases and volatile substances, whose partial vapor pressure is equal to or higher than the water vapor pressure, will be transported across the distillation membrane together with water, causing contamination of the permeate stream. Therefore, the pretreatment of the high-salinity wastewater is necessary, and the pollution of the recovered water by organic matters is avoided.
In the technical scheme, the inventor uses ferrous sulfate and hydrogen peroxide to carry out oxidation treatment on organic matters in the high-salinity wastewater, so that the content of the organic matters in the high-salinity wastewater is reduced. In addition, the inventor also adds the carbon nano tube modified by nickel oxide into the reaction system, the metal element (nickel) on the carbon nano tube modified by nickel oxide is matched with the carbonyl or other coordination groups of the organic matter, so that the attack of nucleophilic reagent is facilitated, and the nickel ions and organic phosphorus form a chelate structure to promote the hydrolysis of the organic phosphorus. The addition of the nickel oxide-modified carbon nanotubes promotes the oxidative decomposition of organic substances and the mineralization of organic phosphorus. The carbon nano tube is used as a support of the nickel oxide, so that the reaction is more sufficient, and in addition, the carbon nano tube and inorganic phosphorus formed by hydrolysis are fully adsorbed, so that the inorganic phosphorus is fully settled. The carbon nano tube modified by the nickel oxide plays the roles of an oxidation reaction promoter and a flocculating agent, and the decomposition, sedimentation and flocculation of organic matters are carried out in one step, so that the reaction steps are saved, and the cost is reduced. The nickel oxide is the most stable oxide of nickel, and the carbon nano tube modified by the nickel oxide also has the characteristic of stable property, so that new substances (salt) cannot be introduced into the high-salinity wastewater to be treated, and secondary pollution cannot be caused to the high-salinity wastewater to be treated.
In the prior art, the carbon nanotube modified by nickel oxide is generally used in the electrochemical field, especially in the preparation of environment-friendly batteries, and the inventor finds that the carbon nanotube modified by nickel oxide can play a role in promoting the degradation of organic matters in sewage and wastewater treatment through long-term practice, namely finds a new function and a new application of the carbon nanotube modified by nickel oxide.
Further, the hydrogen peroxide is 30% hydrogen peroxide; the use amount ratio of the high-salinity wastewater, the ferrous sulfate, the 30% hydrogen peroxide and the nickel oxide modified carbon nano tube is as follows: 400 ml: 3 g: 50 ml: 10 g.
By adopting the technical scheme, the organic matters in the high-salinity wastewater can be fully decomposed, and the forward osmosis efficiency and the membrane distillation efficiency are increased.
Further, the preparation method of the nickel oxide modified carbon nanotube comprises the following steps: acidizing the multi-walled carbon nano-tube, and then crushing the acidized multi-walled carbon nano-tube to obtain acidized carbon nano-tube powder; dispersing the acidified carbon nanotube powder into water to obtain an acidified system, then dropwise adding the nickel ion solution into the acidified system, stirring, and filtering to obtain a precipitate; and calcining the precipitate, and then crushing the precipitate to obtain the nickel oxide modified carbon nanotube.
By adopting the technical scheme, the nickel oxide modified carbon nano tube with the functions of promoting oxidation reaction and flocculating can be prepared.
Further, the acidification treatment method comprises the following steps: preparing a strong acid solution consisting of 70% concentrated nitric acid and 80% concentrated sulfuric acid; the multi-walled carbon nanotubes are treated by using a strong acid solution, and then treated by using a 30% hydrofluoric acid solution.
By adopting the technical scheme, the multiwall carbon nanotubes are respectively treated by different types of acid, so that the surfaces of the multiwall carbon nanotubes can be activated, and nickel ions can be fully adsorbed.
Further, the dosage ratio of the multi-walled carbon nanotube to the strong acid solution is 1 g: 30ml, and acidizing the multi-wall carbon nano-tube by using a strong acid solution at the temperature of 90 ℃ for 24 hours; the using amount ratio of the multi-wall carbon nano tube to the 30% hydrofluoric acid solution is 1 g: 20ml, and acidizing the multi-wall carbon nano-tube by using a 30% hydrofluoric acid solution at the temperature of 50 ℃ for 24 hours.
By adopting the technical scheme, the dosage proportion, the treatment temperature and the treatment time can ensure the sufficient activation of the surface of the multi-wall carbon nano tube.
Further, the volume ratio of the acidification system to the nickel ion solution is 5: 2; the nickel ion solution is NiCl2And (3) solution.
By adopting the technical scheme, the nickel ions are fully adsorbed on the multi-wall carbon nano tube.
Further, the method for calcining the precipitate comprises the following steps: and (3) placing the precipitate in a muffle furnace, and calcining for 3h at 400 ℃ under the nitrogen protection environment.
By adopting the technical scheme, nickel ions attached to the multi-walled carbon nano-tube in the calcining process are converted into nickel oxide.
Further, in the step (2), the temperature of the membrane distilled water supply in the membrane distilled water supply tank is maintained at 90 ℃.
By adopting the technical scheme, the temperature of the membrane distillation water supply is 90 ℃, and water molecules in the membrane distillation water supply can be ensured to fully penetrate through the distillation membrane to enter the permeation side.
Further, the set threshold I is 300000 mu s/cm; the set threshold II is 100000 mu s/cm; the set threshold III is 25000 mu s/cm.
By adopting the technical scheme, the set threshold value can maintain the concentration difference between the raw liquid side and the draw liquid side in the forward osmosis process, and the forward osmosis is ensured to be smoothly carried out.
Drawings
FIG. 1 is a schematic process flow diagram of the process of the present invention.
Detailed Description
The following is further detailed by way of specific embodiments:
the reference numbers are as follows: membrane distillation unit 1, forward osmosis unit 2, dope side 3, forward osmosis membrane 4, draw liquor side 5, distillation membrane 6, membrane distillation feed water tank 7, draw liquor tank 8, forward osmosis feed water tank 9, feed side 10, permeate side 11.
Example 1
1. High salt content of waste water
This technical scheme carries out salt substance concentration and water recovery to high salt waste water, and high salt waste water in this embodiment is formed after the processing such as the conventional suspended solid that removes, and quality of water characteristic parameter is as follows: pH 8, COD 35072mg/L, conductivity 7547 mus/cm, total phosphorus 1351mg/L, NH3-N94 mg/L. The salt substance in the high-salinity wastewater is mainly sodium chloride, and the content of the salt substance is 3.4 w.t%.
Wherein COD is the abbreviation of Chemical Oxygen Demand, refers to the amount of oxidant consumed when a water sample is treated with a strong oxidant, and is an index representing the amount of reducing substances in water, and the reducing substances in water mainly refer to organic substances. COD is an index for measuring the content of organic substances in water, NH3N is an index of the content of ammonia nitrogen in the wastewater, and total phosphorus refers to an index of the content of phosphorus in the wastewater (see GB8978-1996 integrated wastewater discharge standard).
2. High salt wastewater treatment step
(1) Pretreatment: the method for pretreating the high-salinity wastewater comprises the following steps: adding ferrous sulfate, 30% hydrogen peroxide and nickel oxide modified carbon nano tubes into high-salinity wastewater to obtain a pretreatment system, stirring the pretreatment system at room temperature for 4 hours, standing for 5 hours, and taking supernatant, wherein the supernatant is water supply which is divided into two parts of membrane distillation water supply and forward osmosis water supply. Wherein the use amount ratio of the high-salinity wastewater, the ferrous sulfate, the 30% hydrogen peroxide and the nickel oxide modified carbon nano tube is as follows: 400 ml: 3 g: 50 ml: 10 g.
(2) Membrane distillation and water collection: as shown in fig. 1, the membrane distilled feed water is fed into a membrane distilled feed water tank 7, and the membrane distilled feed water is heated to 90 ℃ in the membrane distilled feed water tank 7. Then conveying the membrane distillation water supply with the temperature of 90 ℃ into a membrane distillation unit 1, carrying out membrane distillation on the membrane distillation water supply to obtain concentrated water and recovered water, collecting the recovered water, and conveying the concentrated water back to a membrane distillation water supply tank 7; when the conductivity of the membrane distillation feed water in the membrane distillation feed water tank 7 is greater than or equal to a set threshold value I (300000 mu s/cm), the membrane distillation feed water in the membrane distillation feed water tank 7 is conveyed to a draw solution tank 8 to obtain draw solution, and the draw solution is naturally cooled in the draw solution tank 8 and is used for forward osmosis after being cooled to room temperature. The distillation membrane 6 used for membrane distillation is a PP hollow fiber membrane of Membrana company, Germany in the prior art, and the effective membrane area is 0.02m2. The flow rate of the material on the membrane surface of the feed side 10 is 0.5m/s, and the vacuum degree of the permeation side 11 is-0.09 MPa.
(3) Forward osmosis: as shown in fig. 1, the forward osmosis feed water is fed into the forward osmosis feed water tank 9, then into the dope side 3 of the forward osmosis unit 2, and then back into the forward osmosis feed water tank 9, with the forward osmosis feed water circulating between the forward osmosis feed water tank 9 and the forward osmosis unit 2. The draw solution is transported from the draw solution tank 8 into the draw solution side 5 of the forward osmosis unit 2 and then back to the draw solution tank 8, the draw solution circulating between the draw solution tank 8 and the forward osmosis unit 2. In the forward osmosis unit 2, water in the forward osmosis feed passes through the forward osmosis membrane 4 from the feed side 3 to the draw side 5. As the forward osmosis membrane 4, a TFC flat membrane of HTI (HTI corporation) of the prior art was used, the active layer of which was oriented toward the feed liquid side 3 and the effective area of which was 0.01m2The flow rate of the material on the two sides of the membrane surface is 0.2 m/s.
(4) Collecting high-salinity water: when the conductivity of the forward osmosis water supply in the forward osmosis water supply tank 9 is more than or equal to a set threshold value II (100000 mu s/cm), collecting part of the concentrated forward osmosis water supply in the forward osmosis water supply tank 9 to obtain high salt water;
(5) regeneration of the draw solution: when the conductivity of the draw solution in the draw solution tank 8 is equal to or less than a set threshold value III (25000. mu.s/cm), a part of the draw solution is sent back to the membrane distillation water supply tank 7, and the salt ion concentration is increased by membrane distillation.
3. Preparation of nickel oxide modified carbon nano-tube
Preparing a strong acid solution: the strong acid solution consists of 70% concentrated nitric acid and 80% concentrated sulfuric acid, and the volume ratio of the 70% concentrated nitric acid to the 80% concentrated sulfuric acid is 3: 5. Preparing a nickel ion solution: 0.2g of NiCl2·6H20 in 20ml of deionized water, NiCl2·6H2The using ratio of 0 to deionized water is 0.2 g: 20ml, and uniformly mixing by stirring.
The method comprises the steps of preparing a strong acid solution from multi-walled carbon nanotubes (CNT102, the diameter of 8nm, the length of 20 mu m, Beijing German island) to obtain a nanotube-strong acid system, placing the nanotube-strong acid system in an environment with the temperature of 90 ℃ for acidification for 24 hours, washing the system with deionized water after the acidification is finished, filtering the system, and taking the multi-walled carbon nanotubes to finish the first acidification treatment (the dosage ratio of the multi-walled carbon nanotubes to the strong acid solution is 1 g: 30 ml). And then placing the multi-walled carbon nanotube in a 30% hydrofluoric acid solution to obtain a nanotube-hydrofluoric acid system, placing the nanotube-hydrofluoric acid system in an environment at 50 ℃ for acidification for 24 hours, washing the nanotube-hydrofluoric acid system with deionized water after the acidification is finished, and filtering the nanotube to obtain the multi-walled carbon nanotube, thereby completing the secondary acidification treatment (the dosage ratio of the multi-walled carbon nanotube to the 30% hydrofluoric acid solution is 1 g: 20 ml). And finally, drying the multi-walled carbon nano-tube, and grinding the solid into powder to obtain acidified carbon nano-tube powder.
Dispersing the acidified carbon nanotube powder in deionized water to obtain an acidified system, wherein the use amount ratio of the acidified carbon nanotube powder to the deionized water is 1 g: 40 ml. And slowly dropwise adding the nickel ion solution into the acidification system, wherein the volume ratio of the nickel ion solution to the acidification system is 2:5, so as to obtain a nickel ion-nanotube system, adjusting the pH value of the nickel ion-nanotube system to 10 by using ammonia water, stirring for 24 hours, and filtering to obtain a precipitate.
And grinding and crushing the precipitate, putting the crushed precipitate into a muffle furnace, calcining for 3h at 400 ℃ in a nitrogen protection environment, taking out a calcined product, cooling to room temperature, and grinding and crushing the calcined product to obtain the nickel oxide modified carbon nanotube.
4. Comparison of the characteristic parameters of the end product and of the intermediate product
The results of the examination of the high-salinity wastewater, the feed water obtained in step (1), the recovered water obtained in step (2), and the high-salinity water obtained in step (4) are shown in table 1. The water recovery rate calculation method comprises the following steps: the water recovery ratio (%) — the mass of recovered water/the mass of high-salinity wastewater × 100%, and in this example, the water recovery ratio was 96.23%.
Table 1:
| test object | COD(mg/L) | Conductivity (μ s/cm) | Total phosphorus (mg/L) | NH3-N(mg/L) |
| High salt waste water | 35072 | 7547 | 1351 | 94 |
| Water supply | 1201 | 8278 | 21 | 26 |
| Recovering water | 4 | 5 | 0 | 0 |
| High salt water | 484 | 138713 | 4 | 21 |
Example 2
This embodiment is basically the same as embodiment 2, except that: the water quality characteristic parameters of the high-salinity wastewater are as follows: pH 7.5, COD 27891mg/L, conductivity 5147 mus/cm, total phosphorus 587mg/L, NH3-N156 mg/L. The salt substance in the high-salinity wastewater is mainly sodium sulfate, and the content of the salt substance is 3.0 w.t%. The characteristic parameter pairs of the end product and the intermediate product are shown in Table 2. In this example, the water recovery was 94.56%.
Table 2:
| test object | COD(mg/L) | Conductivity (μ s/cm) | Total phosphorus (mg/L) | NH3-N(mg/L) |
| High salt waste water | 27891 | 5147 | 587 | 156 |
| Water supply | 874 | 6153 | 15 | 66 |
| |
3 | 4 | 0 | 0 |
| High salt water | 326 | 178393 | 3 | 49 |
Comparative example 1
This comparative example is substantially the same as example 1 except that: the high-salinity wastewater is directly subjected to membrane distillation and forward osmosis treatment without pretreatment. The characteristic parameter pairs of the end product and the intermediate product are shown in Table 3.
Table 3:
comparative example 2:
this comparative example is substantially the same as example 1 except that: the pretreatment method of the high-salinity wastewater only uses ferrous sulfate and 30 percent hydrogen peroxide to treat the high-salinity wastewater. The characteristic parameter pairs of the end product and the intermediate product are shown in Table 4.
Table 4:
| test object | COD(mg/L) | Conductivity (μ s/cm) | Total phosphorus (mg/L) | NH3-N(mg/L) |
| High salt waste water | 35072 | 7547 | 1351 | 94 |
| Water supply | 21458 | 7798 | 845 | 61 |
| Recovering water | 11946 | 4 | 184 | 51 |
| High salt water | 21478 | 112546 | 874 | 71 |
Analyzing the characteristic parameters of comparative example 1 and example 2 and comparative example 1 and comparative example 2, the method combining forward osmosis and membrane distillation of the technical scheme has higher water recovery rate and salt enrichment efficiency. Comparative example 1 no pretreatment of high-salinity wastewater before forward osmosis and membrane distillation resulted in a relatively large influence on the membrane distillation process, a large amount of organic matter, total phosphorus, etc. in the recovered water, and the recovered water was severely polluted, indicating that pretreatment was a very necessary step for high-salinity wastewater. Otherwise, the organic matter and volatile matter in the high-salinity wastewater can damage the distillation membrane, and the membrane distillation effect is affected. Comparative example 2 high-salinity wastewater is treated without using the nickel oxide-modified carbon nanotube, and organic matters, total phosphorus and total carbon nitrogen are not sufficiently removed, so that the subsequent forward osmosis and membrane distillation effects are not expected, and the recovered water is seriously polluted.
The foregoing is merely an example of the present invention and common general knowledge of known specific structures and features of the embodiments is not described herein in any greater detail. It should be noted that, for those skilled in the art, without departing from the structure of the present invention, several changes and modifications can be made, which should also be regarded as the protection scope of the present invention, and these will not affect the effect of the implementation of the present invention and the practicability of the patent. The scope of the claims of the present application shall be determined by the contents of the claims, and the description of the embodiments and the like in the specification shall be used to explain the contents of the claims.
Claims (8)
1. The method for treating the salt-containing wastewater by adopting forward osmosis membrane distillation is characterized by comprising the following steps of:
(1) pretreatment: pretreating high-salinity wastewater to obtain water supply, wherein the water supply comprises a membrane distillation water supply part and a forward osmosis water supply part;
(2) membrane distillation and water collection: conveying the membrane distillation water supply into a membrane distillation water supply tank, conveying the membrane distillation water supply into a membrane distillation unit, carrying out membrane distillation on the membrane distillation water supply to obtain concentrated water and recovered water, collecting the recovered water, and conveying the concentrated water back to the membrane distillation water supply tank; when the conductivity of the membrane distillation feed water in the membrane distillation feed water tank is greater than or equal to a set threshold value I, conveying the membrane distillation feed water in the membrane distillation feed water tank to a draw liquid tank to obtain a draw liquid;
(3) forward osmosis: conveying forward osmosis water supply into a forward osmosis water supply tank, conveying the forward osmosis water supply into a stock solution side of a forward osmosis unit, conveying the forward osmosis water supply back to the forward osmosis water supply tank, and circulating forward osmosis water supply between the forward osmosis water supply tank and the forward osmosis unit; conveying the draw solution from the draw solution pool into a draw solution side of the forward osmosis unit, and then conveying the draw solution back to the draw solution pool, wherein the draw solution circularly flows between the draw solution pool and the forward osmosis unit; in the forward osmosis unit, water in forward osmosis feed water enters the draw solution side from the stock solution side through the forward osmosis membrane;
(4) collecting high-salinity water: when the conductivity of the forward osmosis water supply in the forward osmosis water supply tank is greater than or equal to a set threshold value II, collecting the concentrated forward osmosis water supply to obtain high-salt water;
(5) regeneration of the draw solution: when the conductivity of the draw solution in the draw solution pool is less than or equal to a set threshold value III, conveying part of the draw solution into a membrane distillation water supply pool;
in the step (1), the method for pretreating the high-salinity wastewater comprises the following steps: adding ferrous sulfate, hydrogen peroxide and nickel oxide modified carbon nano tubes into the high-salinity wastewater to obtain a pretreatment system; stirring the pretreatment system at room temperature for 4h, standing for 5h, and taking supernatant, wherein the supernatant is water supply;
the preparation method of the nickel oxide modified carbon nano tube comprises the following steps: acidizing the multi-walled carbon nano-tube, and then crushing the acidized multi-walled carbon nano-tube to obtain acidized carbon nano-tube powder; dispersing the acidified carbon nanotube powder into water to obtain an acidified system, then dropwise adding the nickel ion solution into the acidified system, stirring, and filtering to obtain a precipitate; and calcining the precipitate, and then crushing the precipitate to obtain the nickel oxide modified carbon nanotube.
2. The method for treating salt-containing wastewater by forward osmosis membrane distillation according to claim 1, wherein the hydrogen peroxide is 30% hydrogen peroxide; the use amount ratio of the high-salinity wastewater, the ferrous sulfate, the 30% hydrogen peroxide and the nickel oxide modified carbon nano tube is as follows: 400 ml: 3 g: 50 ml: 10 g.
3. The method for treating salt-containing wastewater by forward osmosis membrane distillation according to claim 2, wherein the acidification treatment method comprises the following steps: preparing a strong acid solution consisting of 70% concentrated nitric acid and 80% concentrated sulfuric acid; the multi-walled carbon nanotubes are treated by using a strong acid solution, and then treated by using a 30% hydrofluoric acid solution.
4. The method for treating saline wastewater by forward osmosis membrane distillation according to claim 3, wherein the using amount ratio of the multi-walled carbon nanotubes to the strong acid solution is 1 g: 30ml, and acidizing the multi-wall carbon nano-tube by using a strong acid solution at the temperature of 90 ℃ for 24 hours; the using amount ratio of the multi-wall carbon nano tube to the 30% hydrofluoric acid solution is 1 g: 20ml, and acidizing the multi-wall carbon nano-tube by using a 30% hydrofluoric acid solution at the temperature of 50 ℃ for 24 hours.
5. The method for treating salt-containing wastewater by forward osmosis membrane distillation according to claim 4, wherein the volume ratio of the acidification system to the nickel ion solution is 5: 2; the nickel ion solution is NiCl2And (3) solution.
6. The method for treating salt-containing wastewater by forward osmosis membrane distillation according to claim 5, wherein the method for calcining the precipitate is as follows: and (3) placing the precipitate in a muffle furnace, and calcining for 3h at 400 ℃ under the nitrogen protection environment.
7. The method for treating saline wastewater by forward osmosis membrane distillation according to claim 1, wherein in the step (2), the temperature of the membrane distillation feed water in the membrane distillation feed water tank is maintained at 90 ℃.
8. The method for treating saline wastewater by forward osmosis membrane distillation according to claim 1, wherein the set threshold value I is 300000 μ s/cm; the set threshold II is 100000 mu s/cm; the set threshold III is 25000 mu s/cm.
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Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103073146A (en) * | 2013-02-06 | 2013-05-01 | 上海中科高等研究院 | Waste water treatment method and device based on forward osmosis and membrane distillation |
| CN104591457A (en) * | 2013-11-01 | 2015-05-06 | 中国石油化工股份有限公司 | Forward osmosis coupled membrane distillation wastewater treatment apparatus and method thereof |
| CN104609621A (en) * | 2013-11-01 | 2015-05-13 | 中国石油化工股份有限公司 | High-salt waste water treatment method |
| US9751777B1 (en) * | 2011-04-26 | 2017-09-05 | Mansour S. Bader | Treatment of produced water from unconventional hydrocarbons exploration |
| CN107986382A (en) * | 2017-12-07 | 2018-05-04 | 北京科瑞博远科技有限公司 | A kind of method of microwave irradiation high concentrated organic wastewater |
| CN109912131A (en) * | 2019-04-12 | 2019-06-21 | 宇恒(南京)环保装备科技有限公司 | A kind of high concentration hard-degraded organic waste water processing equipment with high salt and technique |
-
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Patent Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US9751777B1 (en) * | 2011-04-26 | 2017-09-05 | Mansour S. Bader | Treatment of produced water from unconventional hydrocarbons exploration |
| CN103073146A (en) * | 2013-02-06 | 2013-05-01 | 上海中科高等研究院 | Waste water treatment method and device based on forward osmosis and membrane distillation |
| CN104591457A (en) * | 2013-11-01 | 2015-05-06 | 中国石油化工股份有限公司 | Forward osmosis coupled membrane distillation wastewater treatment apparatus and method thereof |
| CN104609621A (en) * | 2013-11-01 | 2015-05-13 | 中国石油化工股份有限公司 | High-salt waste water treatment method |
| CN107986382A (en) * | 2017-12-07 | 2018-05-04 | 北京科瑞博远科技有限公司 | A kind of method of microwave irradiation high concentrated organic wastewater |
| CN109912131A (en) * | 2019-04-12 | 2019-06-21 | 宇恒(南京)环保装备科技有限公司 | A kind of high concentration hard-degraded organic waste water processing equipment with high salt and technique |
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