A salt water evaporation separation device for accelerating evaporation, a salt water evaporation separation method and application

Abstract

This invention relates to the field of saline water treatment, and discloses a brine evaporation and separation device for accelerated evaporation, as well as a method and application for brine evaporation and separation. The brine evaporation and separation device includes a feeding assembly, an evaporation and separation assembly, a salt collection assembly, and a condensate collection assembly. The evaporation and separation assembly includes a super-spreadable polypropylene fiber membrane. The brine can be super-spreaded on the surface of the super-spreadable polypropylene fiber membrane, and then evaporated to obtain water vapor and precipitated salt. The salt collection assembly and the condensate collection assembly are used to collect the salt and water vapor, respectively. The brine separation device of this invention utilizes the excellent spreading performance and large specific surface area of ​​the super-spreadable fiber membrane. When the brine is spread in the fiber membrane, water can evaporate rapidly, and salt crystals precipitate after reaching saturation concentration, making them easy to collect, thereby achieving efficient brine separation.

Description

Technical Field

[0001] This invention relates to the field of saline water treatment, and more specifically to a brine evaporation and separation device, method and application for accelerating evaporation that can be used in seawater desalination, concentrated brine treatment in chemical plants and other fields. Background Technology

[0002] The Earth's surface contains a vast amount of water, but approximately 97% is seawater or brine, with excessively high salinity making it unsuitable for direct consumption. Industrial wastewater also contains significant amounts of saline wastewater. Separating salt and water is crucial for addressing the current shortage of freshwater resources and the pollution caused by saline wastewater. This separation can both desalinate brine to produce drinkable freshwater and treat heavily polluting saline wastewater. Currently, the world possesses abundant saline resources, such as seawater and industrial saline wastewater, which contain high concentrations of calcium, magnesium, and sodium ions. Existing technologies for treating saline wastewater typically employ physical and electrochemical methods, such as membrane separation and electrolysis. However, these technologies suffer from high energy consumption and high costs. For example, reverse osmosis membranes, a current technology, are extremely expensive for treating saline wastewater, making them unaffordable for most companies.

[0003] Therefore, there is a need to develop a simple, low-energy-consumption, and efficient brine separation method. Summary of the Invention

[0004] To address the technical problems existing in the prior art, this invention provides a brine evaporation and separation device. This device uses a polypropylene membrane material with water superspreading properties as an accelerated evaporation interface. Utilizing the material's rapid water transfer characteristics and its high specific surface area, water in the brine is rapidly evaporated. The dried and dehydrated crystalline salt precipitates on the membrane material surface and is easily detached, achieving salt and water separation. This device can be used for seawater desalination and the treatment of saline wastewater from chemical plants, and is characterized by high efficiency and ease of operation.

[0005] A first aspect of the present invention is to provide a brine evaporation and separation apparatus, comprising a feeding assembly, an evaporation and separation assembly, a salt collection assembly, and a condensate collection assembly; wherein the evaporation and separation assembly comprises an ultra-spreadable polypropylene fiber membrane; wherein the feeding assembly is capable of distributing brine from the outside onto the surface of the ultra-spreadable polypropylene fiber membrane in the evaporation and separation assembly; the brine is capable of ultra-spreading on the surface of the ultra-spreadable polypropylene fiber membrane, and then evaporating to obtain water vapor and precipitated salt; the salt collection assembly and the condensate collection assembly are respectively used to collect the salt and water vapor;

[0006] The super-spreadable polypropylene fiber membrane comprises a polypropylene fiber membrane matrix and an amphiphilic polymer. Based on the mass of the super-spreadable polypropylene fiber membrane as 100%, the content of the polypropylene fiber membrane matrix in the super-spreadable polypropylene fiber membrane is 93%-99.99%; and the content of the amphiphilic polymer is 0.01%-7%.

[0007] According to the present invention, preferably, the static contact angle between the polypropylene fiber membrane and water can reach 0° within a time of no more than 1 second.

[0008] Superspreading (also known as superdiffusion or superwetting) is a common term in this field. For example, the paper "Superspreading Phenomenon and Essence of Silicon Surfactants" in the 8th issue of *Daily Chemicals Science* (2019) and the paper "Research Progress on the Superspreading Characteristics of Fluids on Solid Surfaces" in the 3rd issue of Volume 65 of *Journal of Chemical Industry and Engineering* (March 2014) both describe superspreading. Generally, it refers to the ability of small-volume droplets (below 2 μl, excluding the influence of gravity) to quickly achieve a contact angle of 0° upon contact with an object's surface. For instance, the superspreading polypropylene fiber membrane of this invention achieves a static contact angle of 0° for water within no more than 1 second, preferably within 0.005 seconds to 1 second. Materials with superspreading properties have better hydrophilicity than traditional superhydrophilic materials (contact angle less than 5°), allowing liquids to rapidly transfer and flow within the material, resulting in high throughput and significant advantages in separation, filtration, and other fields. The superspreading polypropylene fiber membrane of this invention refers to a water-superspreading polypropylene fiber membrane.

[0009] According to the present invention, the super-spreadable polypropylene fiber membrane has excellent hydrophilic properties, which can enable water to be rapidly transferred within the fiber membrane surface in a very short time, spread within the fiber membrane, and form a large specific surface area, which can evaporate water more quickly. It is a key component of the brine evaporation separation device of the present invention. The preferred embodiment of the super-spreadable polypropylene fiber membrane of the present invention is described in detail below.

[0010] According to the present invention, the super-spreadable polypropylene fiber membrane comprises a polypropylene fiber membrane matrix and an amphiphilic polymer. Based on the mass of the super-spreadable polypropylene fiber membrane, the content of the polypropylene fiber membrane matrix in the super-spreadable polypropylene fiber membrane is 93%-99.99%; the content of the amphiphilic polymer is 0.01%-7%; and the static contact angle between the polypropylene fiber membrane and water can reach 0° within no more than 1 second. In a preferred embodiment of the present invention, based on the mass of the super-spreadable polypropylene fiber membrane, the content of the polypropylene fiber membrane matrix in the super-spreadable polypropylene fiber membrane is 95%-99.95%, for example, 95%, 97%, 98.3%, 99%, 99.95%, or any two values ​​or any range of any two values; the content of the amphiphilic polymer is 0.05%-5%, for example, 0.01%, 0.7%, 3%, 5%, or any two values ​​or any range of any two values.

[0011] Preferably, the sum of the content of the polypropylene fiber membrane matrix and the content of the amphiphilic polymer is 100%.

[0012] According to the present invention, the mass content of the amphiphilic polymer in the superspreadable polypropylene fiber membrane can be detected using conventional detection methods in the art. These methods include, but are not limited to, the following: weigh the unmodified polypropylene fiber membrane (m1), treat it according to the methods listed in the examples, and then dry it to obtain the treated polypropylene fiber membrane (m2). The mass content of the amphiphilic polymer is calculated as (m2-m1) / m2×100%.

[0013] According to the present invention, the selectable range of amphiphilic polymer content per unit surface area of ​​the super-spreadable polypropylene fiber membrane is relatively wide. In a preferred embodiment of the present invention, the amphiphilic polymer content per unit surface area of ​​the super-spreadable polypropylene fiber membrane is 0.005 g / m². 2 -3g / m 2 The preferred value is 0.005 g / m 2 -2g / m 2 For example, 0.005g / m 2 1g / m 2 2g / m 2 , and any two values ​​or any interval of any two values.

[0014] According to the present invention, the content of amphiphilic polymer per unit surface area of ​​the super-spreadable polypropylene fiber membrane can be detected using conventional detection methods in the art. These methods include, but are not limited to, the following: First, the sample to be tested is coated with gold on its surface. Then, the coated sample is placed on an SEM detection stage, and a 5μm × 5μm area on the sample is scanned using SEM. Then, the mass fraction of oxygen in this area is determined using EDS energy dispersive spectroscopy for the unmodified polypropylene fiber membrane and the hydrophilically modified polypropylene fiber membrane, denoted as w0 and w1 respectively. The oxygen content is then calculated using the following formula: W = (w1 - w0) / (M O / M A )×M, where M O M is the relative atomic mass of oxygen. A M is the molecular weight of a single unit of the amphiphilic polymer, M is the areal density of the polypropylene fiber membrane, and W is the content of the amphiphilic polymer per unit area of ​​the super-spreadable polypropylene fiber membrane.

[0015] According to the present invention, the polypropylene fiber membrane matrix can be selected from a wide range of options. For example, the fiber membrane matrix can be meltblown polypropylene nonwoven fabric, spunbond polypropylene nonwoven fabric, or a multilayer composite fabric of meltblown polypropylene nonwoven fabric and spunbond polypropylene nonwoven fabric.

[0016] According to the present invention, when the fiber diameter of the fiber membrane is within a certain range, capillary forces can be generated between the fibers, thereby improving the hydrophilicity of the polypropylene fibers through self-assembled amphiphilic polymers, allowing water to spread at an extremely rapid speed under the action of capillary forces. In a preferred embodiment of the present invention, the fiber diameter in the superspreadable polypropylene fiber membrane is less than 20 micrometers, preferably less than 10 micrometers, and more preferably 0.1-10 micrometers.

[0017] The fiber diameter range of the polypropylene fiber membrane matrix described in this invention refers to the nominal fiber diameter range or statistically obtained value of commercially available polypropylene fiber membrane matrices in the art. Where the nominal fiber diameter range or statistically obtained value is within the scope of this invention, even if some (or a few) fibers in the overall polypropylene fiber membrane matrix have diameter ranges outside the scope of this invention, they are still within the protection scope of this invention.

[0018] The above methods for detecting fiber diameter can employ conventional testing techniques in this field, including but not limited to observing fibers under microscopes such as electron microscopes and optical microscopes, and measuring and statistically analyzing the fiber diameter.

[0019] According to the present invention, only amphiphilic and water-soluble polymers can achieve capillary self-assembly. In a preferred embodiment of the present invention, the amphiphilic polymer is selected from polyvinyl alcohol. The present invention achieves the coating of amphiphilic polymers on the surface of polypropylene fibers through capillary self-assembly, thereby achieving superhydrophilic and superspreading effects. Experimental verification has shown that non-amphiphilic polymers cannot improve polypropylene fiber membranes.

[0020] According to the present invention, the water-soluble amphiphilic copolymer refers to a polymer whose molecular chain contains both hydrophilic and lipophilic segments. Such polymers exhibit a certain affinity for two phases with different properties (usually an aqueous phase and an oil phase). Preferably, the amphiphilic polymer is polyvinyl alcohol and / or a crosslinked polymer formed from polyvinyl alcohol and a crosslinking agent; more preferably, it is a crosslinked polymer formed from polyvinyl alcohol and a crosslinking agent.

[0021] According to the present invention, in order to ensure the long-term and efficient operation of the separation device, the amphiphilic polymer preferably undergoes a crosslinking reaction. The range of crosslinking agents is relatively wide. In a preferred embodiment of the present invention, the crosslinking agent is selected from at least one of polybasic acids and polybasic aldehydes, including but not limited to at least one of glutaraldehyde and boric acid.

[0022] According to the present invention, the crosslinking agent is preferably selected from at least one of polybasic acids and polybasic aldehydes, more preferably glutaraldehyde and / or boric acid.

[0023] According to the present invention, the super-spreadable polypropylene fiber membrane is a superhydrophilic polypropylene fiber membrane without a layered structure.

[0024] The layered structure refers to the layering of the modified fiber membrane (or fiber cloth). Taking an amphiphilic polymer-modified fiber membrane as an example, a layered amphiphilic polymer layer is formed on the surface of the fiber membrane substrate, with the fiber membrane substrate lining one side of the amphiphilic polymer layer. Existing technologies mainly involve modified fiber membranes with layered structures, forming functional material layers (e.g., polymer layers or inorganic layers) on one or both sides of the membrane substrate. These functional material layers are macroscopically independent layered structures from the membrane substrate. The small amount of functional material penetrating into the membrane substrate has negligible weight and thickness compared to the functional material in the functional material layer, unlike the non-layered polymer in this invention.

[0025] The super-spreadable polypropylene fiber membrane of the present invention is a super-hydrophilic polypropylene fiber membrane without a layered structure. The amphiphilic polymer in the present invention does not have the above-mentioned layering. Instead, the amphiphilic polymer is wrapped around the outside of each fiber of the polypropylene fiber membrane.

[0026] According to the present invention, preferably, the amphiphilic polymer can self-assemble on the surface of the polypropylene fiber membrane matrix, with the oleophilic segments of the amphiphilic polymer assembling on the surface of the polypropylene fibers and the hydrophilic segments distributed on the fiber surface after assembly, thereby improving the hydrophilicity of the polypropylene fiber membrane. Preferably, the superspreadable polypropylene fiber membrane contains polypropylene fibers coated with the amphiphilic polymer, which can be observed under a transmission electron microscope after staining with ruthenium.

[0027] In a preferred embodiment of the present invention, the superspreadable polypropylene fiber membrane contains polypropylene fibers coated with an amphiphilic polymer. Preferably, the amphiphilic polymer is coated onto the polypropylene fibers through capillary self-assembly. That is, self-assembly is achieved under the action of capillary force, with the oleophilic segments of the amphiphilic polymer adhering to the surface of the polypropylene fibers and the hydrophilic segments exposed, thereby forming a fiber surface with a hydrophilic structure. In application, the capillary structure of the fiber membrane itself is well preserved, and with the effect of the amphiphilic polymer, a hydrophilic / superspreadable effect is achieved under the action of capillary force. The amphiphilic polymer on the superspreadable polypropylene fiber membrane of the present invention is different from that cast or coated on the surface of the fiber membrane. The hydrophilicity distribution of the amphiphilic polymer in the present invention is more uniform, and the superspreadable polypropylene fiber membrane of the present invention does not have an obvious layered structure.

[0028] In a preferred embodiment of the present invention, the method for preparing the super-spreadable polypropylene fiber membrane includes:

[0029] The method involves contacting a polypropylene fiber membrane matrix with a solution containing an amphiphilic polymer under external force, wherein the content of the amphiphilic polymer in the solution is not higher than 5 wt%. Optionally, the polypropylene fiber membrane obtained after contacting the polypropylene fiber membrane matrix with the amphiphilic polymer is subjected to a crosslinking reaction in a solution containing a crosslinking agent to obtain the super-spreadable polypropylene fiber membrane.

[0030] As described above, the amphiphilic polymer achieves self-assembly under capillary action. The oleophilic segments of the amphiphilic polymer adhere to the surface of the polypropylene fiber, while the hydrophilic segments are exposed, thus forming a fiber surface with a hydrophilic structure (i.e., the amphiphilic polymer is wrapped around the fiber surface), achieving a hydrophilic / superspreading effect under capillary action. The amphiphilic polymer in this invention has a more uniform distribution and does not have a layered structure.

[0031] Preferably, the contact is carried out in a solution containing an amphiphilic polymer.

[0032] The contact process utilizes intermolecular forces to enable the amphiphilic polymer to self-assemble on the surface of the polypropylene fiber membrane, resulting in a polypropylene fiber membrane coated with the amphiphilic polymer. Specifically, the water-soluble amphiphilic polymer (hydrophilic, oleophilic, and soluble in water) used in this invention allows the water-soluble polymer molecular chains to be dispersed in water and loaded onto the surface of the polypropylene fibers through self-assembly, thereby forming a fiber membrane with superhydrophilic properties. The superspreadable polypropylene fiber membrane achieves hydrophilic modification of the polypropylene fiber membrane by the amphiphilic polymer through capillary self-assembly.

[0033] This invention, through experiments, reveals that, through external force induction, water-soluble polymers with both hydrophilic and oleophilic segments can be self-assembled with polypropylene fiber membranes. Since polypropylene is an oleophilic polymer, the oleophilic segments of the water-soluble polymer assemble onto the fiber surface of the polypropylene fiber membrane. The hydrophilic segments, however, have weaker interactions with the polypropylene fibers and cannot assemble onto the fiber surface, thus remaining exposed. This process endows the polypropylene fibers with hydrophilic properties, and consequently, the polypropylene fiber membrane possesses both hydrophilic and oleophilic properties, with a rapid spreading time. Meanwhile, the fiber diameter in the polypropylene fiber membrane of the present invention is preferably less than 20 micrometers, preferably less than 10 micrometers, and more preferably 0.1-10 micrometers, which can generate strong capillary action. Water can be rapidly transferred along the fiber under the action of capillary force, thereby giving the polypropylene fiber membrane excellent spreading performance. The maximum size of the spreading area after the 2μL droplet is spread in the fiber membrane is not less than 7mm, the maximum size of the spreading area after the 5μL droplet is spread in the fiber membrane is not less than 8mm, the maximum size of the spreading area after the 8μL droplet is spread in the fiber membrane is not less than 12mm, and the maximum size of the spreading area after the 12μL droplet is spread in the fiber membrane is not less than 15mm.

[0034] In a preferred embodiment of the present invention, the content of the amphiphilic polymer in the solution is 0.05-4.5 wt%, preferably 0.1-4.5 wt%. Under the above-mentioned amphiphilic polymer concentration conditions and the action of external force, the contact utilizes intermolecular forces to cause the amphiphilic polymer to self-assemble on the surface of the polypropylene fiber membrane, thereby obtaining a polypropylene fiber membrane coated with the amphiphilic polymer.

[0035] As described above, the content of the amphiphilic polymer in the solution containing the amphiphilic polymer is 0.05-4.5 wt%, preferably 0.1-4.5 wt%, for example 0.1 wt%, 0.5 wt%, 1 wt%, 1.5 wt%, 2 wt%, 2.5 wt%, 3 wt%, 3.5 wt%, 4 wt%, 4.5 wt%, and any two values ​​or any range of any two values, more preferably 0.3-3 wt%.

[0036] In a more preferred embodiment of the present invention, the contact is carried out in a solution containing an amphiphilic polymer, thereby resulting in a more uniform superspreading property of the obtained polypropylene fiber membrane.

[0037] According to the present invention, the contact between the fiber membrane and the amphiphilic polymer can be carried out over a wide temperature range, preferably not exceeding the melting temperature of polypropylene and the amphiphilic polymer, and more preferably not exceeding the glass transition temperature of the amphiphilic polymer.

[0038] In a preferred embodiment of the present invention, the preparation method further includes a step of drying the polypropylene fiber membrane matrix after it comes into contact with the amphiphilic polymer; preferably, the contact temperature and the drying temperature do not exceed the melting temperature of the fiber membrane matrix and the amphiphilic polymer, more preferably they do not exceed the glass transition temperature of the amphiphilic polymer.

[0039] According to the present invention, preferably, the contact is carried out under the action of external force; during the self-assembly of the amphiphilic polymer on the surface of polypropylene fiber, external force can be used to induce it to quickly achieve assembly, and the external force includes, but is not limited to, one or more of the following methods: ultrasound, rolling, filtration, lamination, molding, etc.

[0040] According to the present invention, the conditions for the application of external force are wide-ranging, such as the processing time, the number of processing times, and the process conditions of the processing method, without specific limitations.

[0041] Preferably, the external force is applied in a manner that includes one or more of the following: ultrasonication, rolling, filtration, lamination, and molding; more preferably,

[0042] The conditions for ultrasound include: the frequency of the ultrasound is not less than 5 kHz, preferably not less than 10 kHz, such as 10 kHz, 20 kHz, 30 kHz, 40 kHz, 45 kHz, 50 kHz, 55 kHz, and 60 kHz. The higher the ultrasonic power, the fewer the intervals and number of treatments.

[0043] According to the present invention, the ultrasonic processing equipment can be selected from conventional ultrasonic processing equipment, including but not limited to ultrasonic cleaning tables, cell disruptors, ultrasonic probes, industrial ultrasonic devices, etc. The present invention does not particularly limit the power of the specific ultrasonic processing equipment; preferably, the power is 50-750W, more preferably 50-500W, and even more preferably 150-350W.

[0044] According to the present invention, the ultrasonic treatment time in the preparation step can be selected within a wide range. The ultrasonic time is related to the solution concentration, fiber diameter, and areal density. According to the process conditions of the embodiments of the present invention, preferably, the ultrasonic time is not less than 1 minute, more preferably not less than 5 minutes, and more preferably 10-120 minutes, for example, it can be 10 minutes, 20 minutes, 30 minutes, 40 minutes, 60 minutes, 100 minutes, 120 minutes, etc.

[0045] In another preferred embodiment of the present invention, the filtration conditions can be selected over a wide range, and the processing time and number of processes can be reduced as the vacuum level increases. In a preferred embodiment of the present invention, the filtration conditions include: a vacuum level of not less than 5 Pa, preferably not less than 10 Pa, and / or a filtration time of not less than 1 second, preferably not less than 5 seconds. Preferably, the amphiphilic polymer solution remains wetted in the polypropylene fiber membrane matrix until filtration is stopped.

[0046] In another preferred embodiment of the present invention, the conditions for roller pressing include: pressure not less than 5 Pa, preferably not less than 10 Pa; and roller pressing times not less than 1 time.

[0047] In a more preferred embodiment of the present invention, the preparation method may include the following steps:

[0048] The polypropylene fiber membrane matrix is ​​brought into contact with a solution containing an amphiphilic polymer under external force; an aqueous solution of the amphiphilic polymer is then immersed in the polypropylene fiber membrane matrix; and the membrane is then dried.

[0049] As described above, in a preferred embodiment of the present invention, the amphiphilic polymer is selected from polyvinyl alcohol. That is, self-assembly is achieved under capillary action, with the oleophilic segments of the amphiphilic polymer adhering to the surface of the polypropylene fiber, while the hydrophilic segments are exposed, thereby forming a fiber surface with a hydrophilic structure. In application, the capillary structure of the fiber membrane itself is well preserved, and with the added effect of the amphiphilic polymer, a hydrophilic / superspreading effect is achieved under capillary action.

[0050] The amphiphilic polymer on the superspreadable polypropylene fiber membrane of this invention differs from amphiphilic polymers cast or coated onto the surface of the fiber membrane. The amphiphilic polymer of this invention exhibits a more uniform hydrophilic distribution, and the superspreadable polypropylene fiber membrane of this invention does not have a significant layered structure. Furthermore, the amphiphilic polymer of this invention coats the surface of the fibers, rather than being cast or coated onto one side of the fiber membrane. This ensures excellent retention of capillary action between the fibers in this invention. Combined with the effect of the amphiphilic polymer, this allows water to achieve a hydrophilic / superspreading effect under capillary force during application.

[0051] According to the present invention, there are no particular limitations on the molecular weight of the amphiphilic polymer; for example, the number average molecular weight can be 30,000-300,000. Taking the embodiments described later as examples, polyvinyl alcohol with a degree of polymerization of 1700 can be selected.

[0052] According to the present invention, the polypropylene fiber membrane matrix can be selected from a wide range of materials, such as meltblown polypropylene nonwoven fabric, spunbond polypropylene nonwoven fabric, meltblown and spunbond polypropylene composite nonwoven fabric, spunlace polypropylene nonwoven fabric, etc. According to the present invention, meltblown polypropylene nonwoven fabric and meltblown and spunbond polypropylene composite nonwoven fabric are preferred.

[0053] According to the present invention, preferably, the areal density of the polypropylene fiber membrane matrix is ​​10-60 g / m³. 2 Preferably 20-50g / m 2 And / or, the fiber diameter is not greater than 20 micrometers, preferably less than 10 micrometers, and more preferably 0.1-10 micrometers. In this preferred embodiment, the fiber diameter of the fiber membrane generates capillary forces between the fibers, thereby improving the hydrophilicity of the polypropylene fibers through self-assembled amphiphilic polymers. Upon contact with water, water can spread out at an extremely rapid speed under the action of capillary forces.

[0054] The fiber diameter range of the polypropylene fiber membrane matrix described in this invention refers to the nominal fiber diameter range or statistically obtained value of commercially available polypropylene fiber membrane matrices in the art. Where the nominal fiber diameter range or statistically obtained value is within the scope of this invention, even if some (or a few) fibers in the overall polypropylene fiber membrane matrix have diameter ranges outside the scope of this invention, they are still within the protection scope of this invention. The fiber diameter detection method can employ conventional methods in the art, including but not limited to observing the fibers under a microscope, such as an electron microscope or an optical microscope, and measuring and statistically analyzing the fiber diameter.

[0055] The preparation method further includes an optional crosslinking step, which can be optionally performed according to the specific application, and preferably includes a crosslinking step.

[0056] In the crosslinking step, the polypropylene fiber membrane obtained by contacting the polypropylene fiber membrane matrix with the amphiphilic polymer is crosslinked in a solution containing a crosslinking agent.

[0057] The cross-linked amphiphilic polymers form a cross-linked structure, which increases the stability of the amphiphilic polymers in the fiber membrane and enhances the hydrophilic stability.

[0058] The aforementioned superspreading stability refers to the change in contact angle after the hydrophilic fiber membrane is completely immersed in deionized water and treated under ultrasonic cleaning conditions for 5 minutes, repeated 3 times. The smaller the change in contact angle, the better its hydrophilic stability.

[0059] According to the present invention, the crosslinking agent can be selected from a wide range. In a preferred embodiment of the present invention, the crosslinking agent is selected from at least one of polybasic acids and polybasic aldehydes, preferably at least one of glutaraldehyde and boric acid, and more preferably glutaraldehyde; and / or,

[0060] The crosslinking agent content in the solution is 0.005-0.8 wt%, preferably 0.01-0.5 wt%; and / or, the crosslinking temperature conditions include:

[0061] The crosslinking temperature does not exceed the glass transition temperature of the amphiphilic polymer, preferably 30-70°C; and / or the pH of the solution containing the crosslinking agent is 4-7; the crosslinking reaction time is 1 min-120 min, preferably 1 min-90 min, for example, it can be 1 min, 3 min, 5 min, 10 min, 20 min, 50 min, 70 min, 90 min, and any two values ​​or any range of any two values.

[0062] The present invention does not have any particular limitations on the raw materials used to adjust the pH; any conventional acid or base raw materials in the art can be used.

[0063] According to the present invention, the cross-linked fiber membrane can be cleaned to remove residual cross-linking agents and other substances. The present invention does not particularly limit the cleaning method, including but not limited to rinsing with water. To improve cleaning efficiency, ultrasonic cleaning is preferred. The ultrasonic conditions are not particularly limited here. For example, the ultrasonic frequency is 20-80 kHz. Preferably, the ultrasonic cleaning time is 1-30 minutes per cycle, more preferably 15-25 minutes per cycle, and the number of cleaning cycles is selected from 1-5 times, preferably 2-4 times.

[0064] According to the present invention, if the superspreadable polypropylene fiber membrane needs to be dried, the drying temperature shall not exceed the glass transition temperature of the amphiphilic polymer. When the processing temperature exceeds the glass transition temperature, the amphiphilic polymer undergoes molecular chain segment movement, which will destroy its self-assembled structure and affect the superspreading performance.

[0065] The above describes the super-spreadable polypropylene fiber membrane of the present invention and its preferred preparation method.

[0066] In a preferred embodiment of the present invention, the super-spreadable polypropylene fiber membrane has at least one of the following characteristics:

[0067] The maximum size of the spreading area after a 2μL droplet is spread on the superspreadable polypropylene fiber membrane is not less than 7mm, the maximum size of the spreading area after a 5μL droplet is spread on the superspreadable polypropylene fiber membrane is not less than 8mm, the maximum size of the spreading area after an 8μL droplet is spread on the superspreadable polypropylene fiber membrane is not less than 12mm, and the maximum size of the spreading area after a 12μL droplet is spread on the superspreadable polypropylene fiber membrane is not less than 15mm.

[0068] The method for detecting the maximum size of the droplet spreading area on the fiber membrane can be performed using conventional detection methods in the art. These methods include, but are not limited to, the following: The fiber membrane sample is flatly attached to a glass slide, ensuring the sample remains horizontal during attachment. The slide is then fixed on the sample stage of a contact angle measuring instrument. The droplet volume is controlled by adjusting the instrument; the volume can be 2 μL, 5 μL, 8 μL, or 12 μL. A droplet is placed in the center of the sample. After the contact angle reaches 0 degrees, the glass slide is removed, and the size of the spreading area is measured. The spreading area is approximately circular; its diameter or diagonal can be taken as the maximum size.

[0069] According to the present invention, the super-spreadable polypropylene fiber membrane can achieve a static contact angle of 0 degrees with water within 1 second; more preferably, it can achieve a static contact angle of 0 degrees with water within 0.005 seconds to 1 second. For example, it can be 0.005 seconds, 0.01 seconds, 0.05 seconds, 0.1 seconds, 0.5 seconds, 0.9 seconds, 1 second, or any two values ​​or any interval between any two values.

[0070] According to the present invention, the time required for the static contact angle between the polypropylene fiber membrane and water to reach 0 degrees can be tested using conventional testing methods in the art. These methods include, but are not limited to, the following: The fiber membrane sample is flatly attached to a glass slide, ensuring the sample remains horizontal during attachment. The slide is then fixed on the sample stage of a contact angle measuring instrument. A water droplet with a volume of less than 2 μL is dropped into the center of the sample. The angle between the solid-liquid interface, through the interior of the droplet, and the vapor-liquid interface at the three-phase interface is measured; this is the static contact angle (referred to as the water contact angle). The time is calculated from the moment the droplet contacts the fiber membrane surface and is lifted off the surface, until the droplet is fully spread and the contact angle reaches 0 degrees. Controlling the volume to less than 2 μL eliminates the influence of gravity, better demonstrating the excellent hydrophilicity and superspreading properties of the polypropylene fiber membrane.

[0071] According to the present invention, preferably, the weight of the super-spreadable polypropylene fiber film per square meter is 9-100 g / m², more preferably 10-50 g / m².

[0072] According to the present invention, preferably, the super-spreadable polypropylene fiber membrane, i.e., the accelerated evaporation membrane, has a high specific surface area. Preferably, the specific surface area of ​​the super-spreadable polypropylene fiber membrane is greater than 0.3 m² / g, and more preferably greater than 0.7 m² / g.

[0073] Experiments revealed that, under the same conditions, accelerated evaporation membranes with a large specific surface area exhibit a faster water evaporation rate. Furthermore, the experiments showed that the spreading speed of water within the accelerated evaporation membrane significantly impacts the evaporation rate; a faster spreading speed allows water to flow more rapidly within the membrane, reducing evaporation rates caused by uneven water distribution. Based on the experimental results, the water evaporation rate should not be less than 3000 ml / hm². 2 Preferably, the water evaporation rate is not less than 4000 ml / hm. 2 More preferably, the water evaporation rate is not less than 4500 ml / hm. 2 Spunbond nonwoven fabrics and other fiber membranes have larger fiber diameters, resulting in a smaller specific surface area, while meltblown fabrics and other fiber membranes have smaller fiber diameters, resulting in a larger specific surface area. Therefore, the weight per square meter of the super-spreadable polypropylene fiber membrane is 9-100 g / m², preferably 10-60 g / m²; the fiber diameter in the fiber membrane is no greater than 20 micrometers, preferably less than 10 micrometers, and more preferably 0.1-10 micrometers. The fiber diameter refers to the average diameter of the fibers in the fiber membrane.

[0074] According to the present invention, preferably, the super-spreadable polypropylene fiber membrane achieves a static contact angle of 0 degrees with water within a time of 0.005 seconds to 1 second.

[0075] In this invention, the super-spreadable polypropylene fiber membrane can be used alone as an accelerated evaporation membrane. To further enhance its mechanical properties, it can also be reinforced with multi-layer hydrophilic membranes, or fixed with other mesh materials.

[0076] According to the present invention, the super-spreadable polypropylene fiber membrane is a key component of the brine evaporation separation device of the present invention. The present invention has described in detail the preferred embodiment and preferred preparation method of the super-spreadable polypropylene fiber membrane of the present invention.

[0077] According to the present invention, the brine evaporation and separation device includes a feeding assembly, an evaporation and separation assembly, a salt collection assembly, and a condensate collection assembly; wherein, the evaporation and separation assembly includes an ultra-spreadable polypropylene fiber membrane; the ultra-spreadable polypropylene fiber membrane is a superhydrophilic polypropylene fiber membrane without a layered structure; wherein, the feeding assembly can distribute brine from the outside onto the surface of the ultra-spreadable polypropylene fiber membrane in the evaporation and separation assembly; the brine can be ultra-spread on the surface of the ultra-spreadable polypropylene fiber membrane, and then evaporated to obtain water vapor and precipitated salt; the salt collection assembly and the condensate collection assembly are used to collect the salt and water vapor, respectively.

[0078] In this invention, the feeding assembly and the evaporation separation assembly can be configured in various ways. For example, the liquid outlet end of the feeding assembly can move relative to the super-spreadable polypropylene fiber membrane in the evaporation separation assembly, or it can remain stationary. Various movement methods can also be employed, as long as the feeding assembly can distribute the brine from the outside onto the surface of the super-spreadable polypropylene fiber membrane in the evaporation separation assembly, rapid evaporation of water from the brine can be achieved, thus fulfilling the purpose of the invention.

[0079] To improve work efficiency, preferably, the outlet end of the feeding component and the super-spreadable polypropylene fiber membrane can move relative to each other, so as to distribute the brine delivered by the outlet end of the feeding component onto the upper surface of the super-spreadable polypropylene fiber membrane.

[0080] In a preferred embodiment of the present invention, the liquid outlet end of the feeding assembly is fixedly arranged, and the super-spreadable polypropylene fiber membrane can move in the horizontal direction or can intermittently rotate around an axis in the horizontal plane. Preferably, the super-spreadable polypropylene fiber membrane can move in a ring in the horizontal direction.

[0081] In another preferred embodiment of the present invention, the liquid outlet end of the feeding assembly can move in the horizontal direction, and the super-spreadable polypropylene fiber membrane is stationary or intermittently rotates around an axis in the horizontal plane or can move in a ring in the horizontal direction.

[0082] According to the present invention, the liquid outlet end of the feeding assembly can be a conventional liquid outlet component in the art, including but not limited to a water pipe and / or a nozzle. The brine may contain inorganic salts such as sodium chloride, sodium sulfate, potassium chloride, sodium phenolate, potassium sulfate, magnesium chloride, and calcium chloride, with a mass fraction typically ranging from 0.1% to 25%. To avoid corrosion of the assembly, the feeding assembly can be made of corrosion-resistant materials or treated with an anti-corrosion coating, using existing technologies.

[0083] According to the present invention, regardless of whether the liquid outlet end of the feeding assembly moves, preferably, the super-spreadable polypropylene fiber membrane is capable of circular motion in the horizontal direction. More preferably, the evaporation separation assembly includes a super-spreadable polypropylene fiber membrane and a transmission module capable of driving the super-spreadable polypropylene fiber membrane to move in a circular motion in the horizontal direction. Preferably, the transmission module includes a circular conveyor belt, and more preferably, the circular conveyor belt has a mesh structure.

[0084] According to the present invention, the evaporation separation component includes an accelerated evaporation membrane, namely the ultra-spreadable polypropylene fiber membrane, and a transmission module. In order to accelerate the evaporation rate, a blower module may also be added to increase the internal airflow.

[0085] The transmission module described in this invention is a device in the prior art that can be used to operate ultra-spreadable fiber membranes. Preferably, the transmission module is a conveyor belt type, in which the ultra-spreadable polypropylene fiber membrane is fixed to a conveyor belt, and a motor drives the conveyor belt to rotate cyclically. Preferably, the conveyor belt is a mesh-like conveyor belt, which can increase the contact between the fiber membrane and the air, thereby increasing the evaporation rate. The conveyor belt material can be any material in the prior art, but is preferably stainless steel or synthetic resin material with corrosion resistance. There are no restrictions on the hydrophilicity of the conveyor belt.

[0086] According to the present invention, in order to improve evaporation efficiency, the evaporation separation assembly preferably further includes a blower module, for example, through which dry compressed air can be introduced.

[0087] At a certain temperature, the evaporation efficiency of the evaporation separation component can be accelerated, but excessively high temperatures will result in significant energy consumption. Existing low-grade heat sources within chemical plants are widely distributed and difficult to recover, making them suitable as supplementary heat sources in this invention, with a temperature range below 100°C. To further accelerate the process, the brine can be preheated; the preheating temperature is related to the heat provided by the low-grade heat source and can be any temperature not exceeding 100°C. Preferably, the ambient temperature during evaporation separation is 40°C-80°C. More preferably, the brine evaporation separation device further includes a heating component, preferably with the heat source of the heating component originating from an externally recovered heat source (e.g., waste liquid with a heat source).

[0088] According to the present invention, the evaporation separation assembly includes a reinforcing material disposed beneath the super-spreadable polypropylene fiber membrane; preferably, the reinforcing material is at least one of a hydrophilic membrane, a hydrophilic and / or hydrophobic mesh material.

[0089] According to the present invention, preferably, the brine evaporation and separation device includes a housing, an evaporation and separation assembly disposed in the inner cavity of the housing, a feeding assembly disposed on the housing and communicating with the inner cavity of the housing, and a condensate collection assembly.

[0090] The condensate collection assembly of the present invention can condense steam using any condensation method in the prior art.

[0091] According to the present invention, preferably, the salt collection component is disposed below the evaporation separation component, or disposed below the shell and connected to the inner cavity of the shell through a closable outlet. Preferably, the salt collection component of the present invention is a corrosion-resistant container that can collect the salt separated by the evaporation separation component, such as inorganic substances like sodium chloride, sodium sulfate, potassium chloride, sodium phenolate, potassium sulfate, magnesium chloride, and calcium chloride.

[0092] For ease of understanding, a preferred embodiment of the brine evaporation and separation device of the present invention will be described below with reference to the accompanying drawings, such as... Figure 1 As shown, the brine evaporation and separation device includes a feeding assembly 1, an evaporation and separation assembly, a condensate collection assembly 3, and a salt collection assembly 5. The evaporation and separation assembly includes an ultra-spreadable polypropylene fiber membrane 2 and a transmission module 4. The transmission module 4 drives the ultra-spreadable polypropylene fiber membrane 2 to move in a horizontal circular motion. During the movement, the feeding assembly 1 distributes brine onto the ultra-spreadable polypropylene fiber membrane 2. The brine is ultra-spread on the surface of the ultra-spreadable polypropylene fiber membrane 2 and evaporates to obtain water vapor and salt precipitated from the ultra-spreadable polypropylene fiber membrane 2. The water vapor is collected in the condensate collection assembly 3. When the salt moves with the ultra-spreadable polypropylene fiber membrane 2 to the bottom of the ring, it falls from the ultra-spreadable polypropylene fiber membrane 2 to the salt collection assembly 5 under the action of gravity or external force (e.g., a scraper).

[0093] Preferably, the lower part of the brine evaporation and separation device is further provided with a liquid outlet, which is preferably connected to the feed assembly 1. This is to collect the unevaporated liquid and, preferably, return it to the feed assembly for refeeding.

[0094] A second aspect of the present invention is to provide a method for performing brine evaporation separation using the brine evaporation separation apparatus described in the first aspect, comprising the following steps:

[0095] (1) The brine is distributed on the super-spreadable polypropylene fiber membrane of the evaporation and separation unit through the feeding assembly;

[0096] (2) The brine is super-spread on the surface of the super-spread polypropylene fiber membrane, and water vapor and salt precipitated from the super-spread polypropylene fiber membrane are obtained by evaporation.

[0097] (3) The water vapor is collected by the condensate collection assembly to obtain condensate; the precipitated salt is collected by the salt collection assembly to obtain salt.

[0098] Preferably, the brine distributed on the superspreadable polypropylene fiber membrane is superspreaded on the surface of the superspreadable polypropylene fiber membrane in the form of droplets.

[0099] According to the present invention, the feed rate of brine can be flexibly adjusted. For example, when the amount of brine fed is much higher than the evaporation rate, some of the brine that cannot be evaporated can be collected at the lower part of the brine evaporation and separation device, that is, at the lower part of the shell. Preferably, the unevaporated brine is collected at the lower part of the brine evaporation and separation device and is preferably returned to the feed assembly through the liquid outlet.

[0100] According to the present invention, the brine has a mass concentration of 0.1%-25%, and the salt therein includes, but is not limited to, sodium chloride, sodium sulfate, potassium chloride, sodium phenolate, potassium sulfate, magnesium chloride, calcium chloride, etc.

[0101] During the separation process, to increase separation efficiency, the brine can be preheated, or the temperature inside the evaporation separation component can be raised to 40-80°C, preferably to 50-80°C. Similarly, to accelerate the evaporation rate, compressed air can be introduced into the evaporation separation component; the amount introduced is unlimited, and the drying rate increases with the increase in the amount introduced.

[0102] In a preferred embodiment of the present invention, the brine separation method includes the following steps:

[0103] (1) Add brine to the evaporation and separation unit through the feed assembly;

[0104] (2) The brine entering the evaporation separation unit quickly spreads on the super-spreading polypropylene fiber membrane. The transmission module drives the super-spreading polypropylene fiber membrane to move, further increasing the spreading area.

[0105] (3) The water begins to evaporate after spreading, and salt crystals are continuously precipitated as the water evaporates. When the amount of salt precipitated reaches a certain level, it begins to fall off into the salt collection component under the action of gravity under the horizontal circular motion of the super-spreadable polypropylene fiber membrane.

[0106] (4) The evaporated water vapor enters the condensate collection component, completing the brine separation;

[0107] Excess unevaporated brine is collected below and returned to the feed assembly.

[0108] The third aspect of the present invention is to provide an application of the brine evaporation and separation device described in the first aspect or the method described in the second aspect in the fields of seawater desalination and concentrated brine treatment in chemical plants.

[0109] The accelerated evaporation brine desalination equipment of the present invention can be applied to brine desalination, wherein the brine includes, but is not limited to, seawater, concentrated brine produced by membrane separation, concentrated brine produced by mechanical evaporation and recompression, saline wastewater from chemical plants, etc.

[0110] Compared with the prior art, the present invention has the following advantages:

[0111] The brine separation device of this invention utilizes the excellent spreading performance and large specific surface area of ​​the ultra-spreadable fiber membrane. When the brine is spread in the fiber membrane, the water can evaporate rapidly, and the salt crystals precipitate after reaching saturation concentration, which is easy to collect, thereby achieving efficient brine separation.

[0112] The super-spreadable fiber membrane in this invention uses polypropylene, which has good corrosion resistance, as the matrix, and can meet the needs of different brine separation applications. Furthermore, the device is simple to operate, consumes little energy, and is easy to promote and implement.

[0113] The polypropylene fiber membrane of this invention possesses the above-mentioned properties through the inventors' unexpected discovery during their research. When the fiber diameter of the polypropylene fiber membrane is less than a certain size, capillary action occurs on the surface and inside the fiber membrane. During contact or impregnation with the amphiphilic polymer aqueous solution, the solution contacts the polypropylene fiber surface through capillary force or with the assistance of external force. When the content of the amphiphilic polymer in the solution is not higher than 5 wt%, the amphiphilic polymer molecular chains in the aqueous solution are uniformly dispersed. The lipophilic segments (segments without hydroxyl groups) exhibit good compatibility with the equally lipophilic polypropylene and undergo self-assembly upon contact with the polypropylene fiber membrane matrix. In this process, the amphiphilic polymer separates the hydrophilic and lipophilic segments, i.e., the lipophilic segments coat the polypropylene fiber surface, while the hydrophilic segments are exposed on the polypropylene fiber surface after self-assembly, thus giving the polypropylene fiber membrane hydrophilic properties. By controlling process conditions (e.g., external force, concentration of the amphiphilic polymer, etc.), thin-layer self-assembly of the amphiphilic polymer on the polypropylene fiber surface can be achieved. Through the combined effects of capillary force and self-assembly, polypropylene fiber membranes contain polypropylene fibers coated with amphiphilic polymers. Optionally, through cross-linking, the polypropylene fiber membranes acquire superspreading properties. This process can occur more effectively under external forces, such as ultrasound. The amphiphilic polymer solution can rapidly penetrate between the fiber membrane fibers, promoting contact between the oleophilic segments and the polypropylene fiber surface, thereby accelerating the speed and efficiency of self-assembly.

[0114] Existing technologies typically use high-cost materials such as fluorine-containing materials, or employ complex processes. The polypropylene fiber membrane used in this invention is characterized by low cost and corrosion resistance, and has the advantage of being easier to industrialize compared to existing high-cost separation equipment such as easily corroded metals. Attached Figure Description

[0115] Figure 1 This is a schematic diagram of a preferred embodiment of the brine separation device of the present invention.

[0116] 1. Feeding assembly; 2. Ultra-spreadable polypropylene fiber membrane; 3. Condensate collection assembly; 4. Transmission module; 5. Salt collection assembly.

[0117] Figure 2 This is a schematic diagram of the brine separation process. Detailed Implementation

[0118] The present invention will now be described in detail with reference to specific embodiments. It should be noted that the following embodiments are only used to further illustrate the present invention and should not be construed as limiting the scope of protection of the present invention. Some non-essential improvements and adjustments made by those skilled in the art based on the content of the present invention are still within the scope of protection of the present invention.

[0119] The experimental data in the examples were measured using the following instruments and methods:

[0120] The water contact angle and spreading time (spreading time is the time required for the water contact angle to reach 0°) obtained in the example were measured using the German EASYDROP contact angle tester: The fiber membrane was cut into a sample of 1cm×1cm size, and then the sample was flatly attached to a glass slide. During the attachment process, care was taken to keep the sample flat in the horizontal direction. Then the glass slide was placed on the sample stage of the EASYDROP contact angle measuring instrument and fixed. The instrument was adjusted to control the volume of 2μL water droplet to the center of the sample. After 10 seconds, the angle between the solid-liquid interface, through the interior of the droplet, and the vapor-liquid interface at the three-phase interface was measured, which is the static contact angle (abbreviated as water contact angle).

[0121] Water spread area test method: Cut the fiber membrane into 3cm×3cm samples, place the samples flat on a flat glass surface, and then use a Masterflex 78018-10 peristaltic pump to draw different volumes of deionized water droplets onto the surface of the fiber membrane. After the water has spread completely, measure the maximum dimension at both ends of the spread area as the spread dimension.

[0122] Liquid content of hydrophilic polypropylene fiber membrane: Take a dried hydrophilic polypropylene fiber membrane and weigh it. Then rinse the sample with deionized water until there is no foam, and suspend it at 25°C and 30% humidity. After no water droplets fall for 1 minute, weigh it again. The difference between the two weighings divided by the mass after drying is the liquid content of the sample, expressed in multiples.

[0123] The mass content of amphiphilic polymer in the polypropylene fiber membrane obtained in the example: Weigh the unmodified polypropylene nonwoven fabric (m1), process it according to the method listed in the example, and then dry it to obtain the processed polypropylene fiber membrane. Weigh the membrane (m2). The mass content of amphiphilic polymer is (m2-m1) / m2×100%.

[0124] The content of amphiphilic polymer per unit surface area of ​​the polypropylene fiber membrane is determined as follows: First, the sample to be tested is coated with gold. Then, the coated sample is placed on an SEM stage, and a 5μm × 5μm area on the sample is scanned using SEM. Then, the mass fraction of oxygen in this area is determined using EDS energy dispersive spectroscopy, and recorded as w0 and w1 respectively. The oxygen content is calculated using the following formula: W = (w1 - w0) / (M O / M A )×M, where M O M is the relative atomic mass of oxygen. A M is the molecular weight of a single unit of the amphiphilic polymer, M is the areal density of the polypropylene nonwoven fabric, and W is the content of the amphiphilic polymer per unit area of ​​the polypropylene fiber membrane.

[0125] Test method for specific surface area of ​​super-spreadable polypropylene fiber membrane: Use mercury porosimeter to test, weigh a certain mass of sample, transfer it into dilatometer, then seal and weigh it; put the weighed dilatometer into low pressure chamber, and then conduct high pressure test, and obtain the specific surface area result by software calculation.

[0126] Processing speed refers to the amount of water sprayed onto the ultra-spreadable polypropylene fiber membrane. The processing speed can be controlled by the pump in the feeding device. Calculation method: Processing speed = Water pump inlet speed / Membrane area.

[0127] In the following examples, polyvinyl alcohol, PVA-1799, has a degree of polymerization of 1700 and a degree of alcoholysis of 99%.

[0128] Preparation Example 1

[0129] Take polypropylene meltblown nonwoven fabric (purchased from Yanshan Petrochemical, specification 25g / m²) 2 Polypropylene (PP) fibers (0.5-8 μm in diameter) were immersed in a 0.3 wt% aqueous solution of polyvinyl alcohol (PVA-1799, glass transition temperature 72℃) at 25℃ and ultrasonically treated at 50 kHz for 30 minutes under a 250W ultrasonic probe. The treated PP meltblown fibers were then crosslinked in a 0.5 wt% glutaraldehyde crosslinking solution (pH 6) at 60℃ for 1 hour. After crosslinking, the PP meltblown fibers were cleaned three times in a 100W ultrasonic water bath at 50 kHz for 20 minutes each time, followed by drying (at 60℃ for 1 hour) to obtain an ultra-spreadable polypropylene fiber membrane.

[0130] The obtained polypropylene fiber membrane was tested for water contact angle, specific surface area, and spreading time. The specific test data are shown in Table 1.

[0131] Preparation Example 2

[0132] A three-layer composite fiber membrane consisting of polypropylene spunbond nonwoven fabric and polypropylene meltblown fabric (purchased from Yanshan Petrochemical, model SMS, specification 50g / m³) was prepared. 2 (The fiber diameter is 0.5-45 micrometers). Except for changing the ultrasonic treatment time when soaking in polyvinyl alcohol aqueous solution to 50 minutes, everything else is the same as in Example 1, and an ultra-spreadable polypropylene fiber membrane is obtained. The specific test data are shown in Table 1.

[0133] Preparation Example 3

[0134] The polypropylene meltblown nonwoven fabric from Preparation Example 1 was immersed in a 0.1 wt% polyvinyl alcohol (from Aladdin, PVA-1799) aqueous solution at 25°C and ultrasonically treated at a frequency of 50 kHz for 30 minutes under a 250 W ultrasonic probe. The treated polypropylene meltblown fabric was then crosslinked in a 0.5 wt% glutaraldehyde crosslinking solution (pH 6) in an 80°C oven for 1 hour. After crosslinking, the polypropylene meltblown fabric was cleaned three times in a 100 W ultrasonic water bath at a frequency of 50 kHz, each time for 20 minutes, and then dried (at 85°C for 1 hour). The glass transition temperature of PVA-1799 is 72°C. Specific test data are shown in Table 1, yielding a modified polypropylene fiber membrane.

[0135] Preparation Example 4

[0136] A 0.8 wt% aqueous solution was prepared using PVA 1750 (purchased from Shandong Jiaying Chemical Technology Co., Ltd.) and deionized water at 90℃. 500 ml of the PVA solution was weighed and mixed with 600 ml of the crosslinking solution to obtain a mixed solution. The crosslinking solution contained 45 ml of glutaraldehyde aqueous solution (50 wt%), as well as acetic acid aqueous solution (10 vol%), methanol aqueous solution (10 vol%), and sulfuric acid aqueous solution (10 vol%), with a volume ratio of 3:2:1. Polypropylene meltblown nonwoven fabric (Sinopec Yanshan Petrochemical, surface density 25 g / m²) was used. 2 The mixture was placed in a mixed solution and vibrated at 150 rpm for 60 minutes at 50°C in a shaking incubator. It was then placed in deionized water for 1 hour to remove residual crosslinking agent and PVA, and finally dried in a 50°C oven for 1 hour to obtain the modified polypropylene fiber membrane. Specific test results are shown in Table 1.

[0137] Preparation Example 5

[0138] The concentration of PVA aqueous solution was changed to 0.1 wt%, the crosslinking agent was changed to boric acid with a mass fraction of 0.5 wt%, and the crosslinking time was 90 minutes. All other operations were the same as in Preparation Example 1. Specific test data are shown in Table 1.

[0139] Example 1

[0140] Take 2000g of salt water (containing 23.5% Na₂SO₄ by mass). The accelerated evaporation membrane used is the ultra-spreadable polypropylene membrane (i.e., ultra-spreadable polypropylene nonwoven fabric) obtained in Preparation Example 1, with a width of 0.25m, a length of 2m, and a membrane area of ​​0.5m². 2 The weight is approximately 12.6g. To accelerate evaporation, the brine is preheated to 60℃ and then added to the inlet assembly. The inlet assembly consists of a water pump and silicone tubing. The water pump flow rate is 150ml / min (Chongqing Jieheng Peristaltic Pump Co., Ltd.), and the silicone tubing diameter is 10mm. The brine drips through the inlet assembly at a rate of 150ml / min onto the surface of the accelerated evaporation membrane and spreads rapidly. The evaporation membrane rotates along with the movement of the transmission module, ensuring the water is evenly dripped onto the surface. The transmission speed is 1m / min. To further accelerate evaporation and promote airflow within the equipment, dry air is blown into the equipment by a blower (Suzhou Pujin Electromechanical, 130FLJ0, 60w). The specific workflow is as follows:

[0141] (1) The conveyor module starts to rotate and the blower starts to work; (2) The water inlet assembly and the condensate collection assembly start to work; (3) The water inlet assembly stops after operating for two minutes to allow the water spread on the evaporation membrane to have sufficient time to evaporate; (4) The water inlet assembly continues to work after a 7-minute pause; (5) Steps (3) and (4) are repeated until 2000ml of brine is processed, which takes 45 minutes.

[0142] After treatment, 1520g of condensate was collected, the evaporation membrane weighed 336g, and 142g of salt was collected in the salt collection device. The processing rate was 18000ml / h·m. 2 ICP analysis of the condensate showed a sodium ion content of 20.49 mg / L.

[0143] Example 2

[0144] The super-spreadable polypropylene fiber membrane obtained in Preparation Example 2 was used instead of the super-spreadable polypropylene fiber membrane in Example 1. The water influent rate was 100 ml / min, and the amount of brine and other conditions remained unchanged. After treatment, 1523 g of condensate was collected, the evaporation membrane mass was 407 g, and 70 g of salt was collected in the salt collection device. The treatment rate was 12000 ml / h·min. 2 .

[0145] Comparative Example 1

[0146] The modified polypropylene fiber membrane obtained in Preparation Example 3 was used instead of the super-spreadable polypropylene fiber membrane in Preparation Example 1 of Example 1, and all other aspects remained unchanged.

[0147] Because Preparation Example 3 could not spread and had poor hydrophilicity, water spilled off as the fiber membrane moved, making brine separation impossible. The amount of condensate collected was far less than in all the other examples.

[0148] Comparative Example 2

[0149] The modified polypropylene fiber membrane obtained in Preparation Example 4 was used instead of the super-spreadable polypropylene fiber membrane in Example 2, with all other aspects remaining unchanged.

[0150] Because Preparation Example 4 could not spread and had poor hydrophilicity, water spilled off as the fiber membrane moved, making brine separation impossible. The amount of condensate collected was far less than in all the other examples.

[0151] Example 3

[0152] The super-spreadable polypropylene fiber membrane obtained in Preparation Example 5 was used instead of the super-spreadable polypropylene fiber membrane in Example 1. The membrane weight was approximately 12.5 g. The brine was an aqueous solution of sodium chloride, wherein the sodium chloride salt content was 3.5% by mass. The amount of brine and other conditions remained unchanged.

[0153] After treatment, 1908g of condensate was collected, the evaporation membrane weighed 63.6g, and 18g of salt was collected in the salt collection device. ICP analysis of the condensate showed a sodium ion content of 21.2mg / L. The treatment rate was 18000ml / h·m. 2 .

[0154] Table 1

[0155]

[0156]

[0157] As can be seen from the above embodiments and comparative examples, the brine separation device of the present invention can utilize the excellent spreading performance and large specific surface area of ​​the ultra-spreadable fiber membrane. When brine is spread in the fiber membrane, water can evaporate rapidly, and salt crystals are precipitated in the process, which are easy to collect, thereby achieving efficient brine separation.

[0158] As can be seen from the embodiments of the present invention, the brine separation device of the present invention has a simple structure, is easy to operate, consumes little energy, can meet different brine separation application scenarios, and is easy to promote and implement.

[0159] It should be noted that the embodiments described above are only for explaining the present invention and do not constitute any limitation on the present invention. The present invention has been described with reference to typical embodiments, but it should be understood that the words used therein are descriptive and explanatory terms, not limiting terms. Modifications can be made to the present invention within the scope of the claims, and revisions can be made to the present invention without departing from the scope and spirit of the present invention. Although the present invention described herein relates to specific methods, materials, and embodiments, it does not mean that the present invention is limited to the specific examples disclosed herein; on the contrary, the present invention can be extended to all other methods and applications with the same function.

[0160] All publications, patent applications, patents, and other references mentioned in this specification are incorporated herein by reference. Unless otherwise defined, all technical and scientific terms used in this specification have the meanings commonly understood by those skilled in the art. In case of conflict, the definitions in this specification shall prevail.

[0161] When this specification uses the prefixes "known to those skilled in the art," "prior art," or similar terms to derive materials, substances, methods, steps, apparatus, or components, the objects derived from such prefixes cover those conventionally used in the art at the time the invention was proposed, but also include those that are not currently commonly used but will become generally recognized in the art as suitable for similar purposes.

[0162] The endpoints and any values ​​of the ranges disclosed in this invention document are not limited to the precise ranges or values; these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein. In the following, various technical solutions can, in principle, be combined with each other to obtain new technical solutions, which should also be considered as specifically disclosed herein.

[0163] In the context of this specification, except where expressly stated otherwise, any matters or issues not mentioned shall apply directly to those known in the art without any modification.

[0164] Furthermore, any implementation described herein can be freely combined with one or more other implementations described herein, and the resulting technical solutions or technical ideas shall be regarded as part of the original disclosure or original record of the present invention, and should not be regarded as new content not disclosed or anticipated herein, unless those skilled in the art consider the combination to be obviously unreasonable.

Claims

1. A brine evaporation and separation device, comprising a feeding assembly, an evaporation and separation assembly, a salt collection assembly, and a condensate collection assembly; wherein, The evaporation separation component includes an ultra-spreadable polypropylene fiber membrane; The feeding assembly can distribute brine from the outside onto the surface of the super-spreadable polypropylene fiber membrane in the evaporation separation assembly; the brine can be super-spread on the surface of the super-spreadable polypropylene fiber membrane, and then evaporated to obtain water vapor and precipitated salt; the salt collection assembly and the condensate collection assembly are used to collect the salt and water vapor, respectively. The super-spreadable polypropylene fiber membrane comprises a polypropylene fiber membrane matrix and an amphiphilic polymer. Based on the mass of the super-spreadable polypropylene fiber membrane as 100%, the content of the polypropylene fiber membrane matrix in the super-spreadable polypropylene fiber membrane is 93%-99.99%; the content of the amphiphilic polymer is 0.01%-7%. The method for preparing the super-spreadable polypropylene fiber membrane includes contacting a polypropylene fiber membrane matrix with a solution containing an amphiphilic polymer under external force, wherein the amphiphilic polymer in the solution is water-soluble and has a content of no more than 5 wt%.

2. The brine evaporation and separation device according to claim 1, characterized in that: Based on the mass of the super-spreadable polypropylene fiber membrane as 100%, the content of the polypropylene fiber membrane matrix in the super-spreadable polypropylene fiber membrane is 95%-99.95%; the content of the amphiphilic polymer is 0.05%-5%; and / or, The super-spreadable polypropylene fiber membrane is a non-layered, superhydrophilic polypropylene fiber membrane; and / or The content of amphiphilic polymer per unit surface area of ​​the super-spreadable polypropylene fiber membrane is 0.005 g / m². 2 -3g / m 2 .

3. The brine evaporation and separation device according to claim 1, characterized in that: The content of amphiphilic polymer per unit surface area of ​​the super-spreadable polypropylene fiber membrane is 0.005 g / m². 2 -2g / m 2 .

4. The brine evaporation and separation apparatus according to claim 1, characterized in that: The fiber diameter in the super-spreadable polypropylene fiber membrane is less than 20 micrometers; and / or, The amphiphilic polymer is selected from polyvinyl alcohol and / or cross-linked polymers formed by polyvinyl alcohol and a cross-linking agent; and / or, The super-spreadable polypropylene fiber membrane contains polypropylene fibers coated with an amphiphilic polymer.

5. The brine evaporation and separation apparatus according to claim 1, characterized in that: The fiber diameter in the super-spreadable polypropylene fiber membrane is less than 10 micrometers; and / or, The amphiphilic polymer is selected from polyvinyl alcohol and / or a cross-linked polymer formed from polyvinyl alcohol and a cross-linking agent; the cross-linking agent is selected from at least one of polybasic acids and polybasic aldehydes; and / or... The super-spreadable polypropylene fiber membrane contains polypropylene fibers coated with an amphiphilic polymer, which is self-assembled onto the polypropylene fibers by capillary force.

6. The brine evaporation and separation apparatus according to claim 1, characterized in that: The fiber diameter in the super-spreadable polypropylene fiber membrane is 0.1-10 micrometers; and / or, The amphiphilic polymer is selected from polyvinyl alcohol and / or cross-linked polymers formed by polyvinyl alcohol and a cross-linking agent; the cross-linking agent is glutaraldehyde and / or boric acid.

7. The brine evaporation and separation apparatus according to claim 1, characterized in that: The contact is carried out in a solution containing an amphiphilic polymer; and / or, The contact utilizes intermolecular forces to enable the amphiphilic polymer to self-assemble on the surface of the polypropylene fiber membrane, resulting in a polypropylene fiber membrane coated with the amphiphilic polymer.

8. The brine evaporation and separation apparatus according to claim 1, characterized in that: The method for preparing the super-spreadable polypropylene fiber membrane further includes a cross-linking reaction of the polypropylene fiber membrane obtained by contacting the polypropylene fiber membrane matrix with the amphiphilic polymer in a solution containing a cross-linking agent to obtain the super-spreadable polypropylene fiber membrane.

9. The brine evaporation and separation apparatus according to claim 1, characterized in that: The content of amphiphilic polymers in the solution is 0.05-4.5 wt%.

10. The brine evaporation and separation apparatus according to claim 1, characterized in that: The amphiphilic polymer content in the solution is 0.1-4.5 wt%.

11. The brine evaporation and separation apparatus according to claim 1, characterized in that: The preparation method further includes a step of drying the polypropylene fiber membrane matrix after it comes into contact with the amphiphilic polymer.

12. The brine evaporation and separation apparatus according to claim 11, characterized in that: The contact temperature and the drying temperature each do not exceed the glass transition temperature of the amphiphilic polymer.

13. The brine evaporation and separation apparatus according to claim 1, characterized in that: The amphiphilic polymer is selected from polyvinyl alcohol; and / or, The areal density of the polypropylene fiber membrane matrix is ​​10-60 g / m³. 2 And / or, the fiber diameter in the polypropylene fiber membrane matrix is ​​not greater than 20 micrometers.

14. The brine evaporation and separation apparatus according to claim 1, characterized in that: The areal density of the polypropylene fiber membrane matrix is ​​20-50 g / m³. 2 And / or, the fiber diameter in the polypropylene fiber membrane matrix is ​​less than 10 micrometers.

15. The brine evaporation and separation apparatus according to claim 1, characterized in that: The fiber diameter in the polypropylene fiber membrane matrix is ​​0.1-10 micrometers.

16. The brine evaporation and separation apparatus according to any one of claims 1-15, characterized in that: The super-spreadable polypropylene fiber membrane has at least one of the following characteristics: The maximum size of the spreading area after a 2 μL droplet spreads on the superspreadable polypropylene fiber membrane is not less than 7 mm; the maximum size of the spreading area after a 5 μL droplet spreads on the superspreadable polypropylene fiber membrane is not less than 8 mm; the maximum size of the spreading area after an 8 μL droplet spreads on the superspreadable polypropylene fiber membrane is not less than 12 mm; and the maximum size of the spreading area after a 12 μL droplet spreads on the superspreadable polypropylene fiber membrane is not less than 15 mm; and / or, The weight of the super-spreadable polypropylene fiber membrane is 9-100 grams per square meter; and / or, The super-spreadable polypropylene fiber membrane has a specific surface area greater than 0.3 m² / g; and / or, The super-spreadable polypropylene fiber membrane achieves a static contact angle of 0 degrees with water within 1 second.

17. The brine evaporation and separation apparatus according to any one of claims 1-15, characterized in that: The super-spreadable polypropylene fiber membrane has at least one of the following characteristics: The weight of the super-spreadable polypropylene fiber membrane is 10-50 g / m²; and / or, The super-spreadable polypropylene fiber membrane has a specific surface area greater than 0.7 m² / g; and / or, The super-spreadable polypropylene fiber membrane achieves a static contact angle of 0 degrees with water within 0.005 seconds to 1 second.

18. The brine evaporation and separation apparatus according to any one of claims 1-15, characterized in that: The outlet end of the feeding assembly can move relative to the super-spreadable polypropylene fiber membrane to distribute the brine delivered by the outlet end of the feeding assembly onto the upper surface of the super-spreadable polypropylene fiber membrane.

19. The brine evaporation and separation apparatus according to claim 18, characterized in that: The liquid outlet end of the feeding assembly is fixedly installed, and the ultra-spreadable polypropylene fiber membrane can move horizontally or intermittently rotate around an axis in the horizontal plane; or... The liquid outlet of the feeding assembly can move horizontally, while the super-spreadable polypropylene fiber membrane remains stationary, or intermittently rotates around an axis in the horizontal plane, or can move in a ring along the horizontal direction.

20. The brine evaporation and separation apparatus according to claim 18, characterized in that: The liquid outlet end of the feeding assembly is fixedly set, and the ultra-spreadable polypropylene fiber membrane can move in a ring along the horizontal direction.

21. The brine evaporation and separation apparatus according to claim 18, characterized in that: The liquid outlet of the feeding assembly is a water pipe and / or a nozzle; the evaporation separation assembly includes an ultra-spreadable polypropylene fiber membrane and a transmission module capable of driving the ultra-spreadable polypropylene fiber membrane to move in a horizontal circular motion.

22. The brine evaporation and separation apparatus according to claim 21, characterized in that: The transmission module includes a ring conveyor belt.

23. The brine evaporation and separation apparatus according to claim 22, characterized in that: The annular conveyor belt has a mesh structure.

24. The brine evaporation and separation apparatus according to any one of claims 1-15, characterized in that: The evaporation separation assembly also includes a blower module.

25. The brine evaporation and separation apparatus according to any one of claims 1-15, characterized in that: The evaporation separation assembly includes a reinforcing material disposed beneath the ultra-spread polypropylene fiber membrane.

26. The brine evaporation and separation apparatus according to claim 25, characterized in that: The reinforcing material is selected from at least one of hydrophilic membranes, hydrophilic and / or hydrophobic mesh materials.

27. The brine evaporation and separation apparatus according to any one of claims 1-15, characterized in that: The brine evaporation and separation device includes a housing, an evaporation and separation assembly disposed within the inner cavity of the housing, a feed assembly disposed on the housing and communicating with the inner cavity of the housing, and a condensate collection assembly; and / or The salt collection component is located below the evaporation separation component, or it is located below the shell and connected to the inner cavity of the shell through a closable outlet.

28. The brine evaporation and separation apparatus according to any one of claims 1-15, characterized in that: The brine evaporation and separation device is also equipped with a liquid outlet at the bottom.

29. The brine evaporation and separation apparatus according to claim 28, characterized in that: The liquid outlet is connected to the feed assembly.

30. A method for brine evaporation separation using the brine evaporation separation apparatus according to any one of claims 1-29, comprising the following steps: (1) The brine is distributed on the super-spreadable polypropylene fiber membrane of the evaporation separation unit through the feeding assembly; (2) The brine is super-spread on the surface of the super-spread polypropylene fiber membrane, and water vapor and salt precipitated from the super-spread polypropylene fiber membrane are obtained by evaporation; (3) The water vapor is collected by the condensate collection assembly to obtain condensate; the precipitated salt is collected by the salt collection assembly to obtain salt.

31. The application of the brine evaporation and separation device according to any one of claims 1-29 or the method according to claim 30 in the fields of seawater desalination and concentrated brine treatment in chemical plants.

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