Real-time analysis method for osmotic energy conversion performance

Abstract

The invention relates to the technical field of information, and particularly provides a real-time analysis method for osmotic energy conversion performance, which comprises the following steps: mixing a natural nanofiber dispersion liquid with a photoresponsive transition metal oxide dispersion liquid, preparing a composite membrane by adopting a membrane forming process, and carrying out heat treatment to remove moisture and improve mechanical strength; the composite film is placed in an electrolyte solution environment to achieve light-induced ion current generation and conversion from permeation energy to electric energy based on the concentration gradient, the light-induced ion current and incident light intensity are in a linear relation, and a base line is recovered after illumination disappears; the osmotic energy conversion power density is enhanced by illumination at an asymmetric concentration gradient.

Description

Technical Field

[0001] This invention belongs to the field of information technology, and in particular relates to a real-time analysis method for permeation energy conversion performance. Background Technology

[0002] In practical applications such as environmental monitoring, marine resource development, and smart agriculture, it is often necessary to simultaneously sense light intensity and harvest energy from natural resources. For example, in coastal wetland monitoring, it is necessary to understand regional light changes to assess the ecological environment, and at the same time, it is desirable to collect infiltration energy at the seawater-freshwater interface to power the monitoring equipment. In field environments, portable devices need both light intensity sensing capabilities and a sustainable energy supply, but current technologies struggle to meet these needs simultaneously.

[0003] Existing technologies suffer from significant functional fragmentation and application limitations. On the one hand, traditional light intensity sensors rely heavily on semiconductor devices, requiring external power supplies and struggling to operate stably in liquid or humid environments. They are prone to performance degradation due to humidity or require complex packaging, making them unsuitable for liquid applications in natural environments. On the other hand, existing permeation energy conversion technologies are mostly single-function designs, capable only of energy harvesting, lacking effective means to enhance conversion efficiency, and unable to be integrated with light intensity detection functions. This results in devices requiring additional sensors and power supply modules in practical applications, leading to complex structures and high deployment costs.

[0004] More importantly, sunlight and permeable energy are valuable resources that coexist in the natural environment of oceans and wetlands, but existing technologies cannot utilize them in a coordinated manner. They cannot achieve power-free light intensity detection through light response characteristics, nor can they further improve the practicality of permeable energy conversion by leveraging sunlight. This results in resource waste and limits the development of integrated and portable equipment.

[0005] Therefore, developing an integrated technical solution that can simultaneously achieve light intensity detection, permeation energy conversion, and real-time analysis of permeation energy conversion performance without requiring an external power source, liquid phase, or humid environment, and addressing the problems of existing technologies being single-function, dependent on external energy sources, and lacking real-time performance feedback, has become a pressing technical challenge. Summary of the Invention

[0006] In view of this, the present invention aims to provide a real-time analysis method for permeation energy conversion performance, so as to solve the problems of light intensity detection, permeation energy conversion, and real-time analysis of permeation energy conversion performance.

[0007] To achieve the above objectives, the technical solution created by this invention is implemented as follows: A composite membrane was prepared by mixing a natural nanofiber dispersion with a photoresponsive transition metal oxide dispersion and then using a film-forming process. The membrane was then subjected to heat treatment to remove moisture and improve mechanical strength. When the composite membrane is placed in an electrolyte solution environment, it can independently realize the generation of photoinduced ion current or the conversion of permeation energy into electrical energy based on concentration gradient. The photoinduced ion current is linearly related to the incident light intensity and recovers the baseline after the light disappears. The permeation energy conversion power density is enhanced by light under an asymmetric concentration gradient. Real-time acquisition of output power data during the permeation energy conversion process enables real-time analysis of permeation energy conversion performance.

[0008] Furthermore, the natural nanofiber dispersion is mixed with the photoresponsive transition metal oxide dispersion, comprising: Obtain the natural nanofiber dispersion and the photoresponsive transition metal oxide dispersion; The natural nanofiber dispersion and the photoresponsive transition metal oxide dispersion are mixed according to the mass ratio determined by the material properties and film formation requirements. The mixture is ultrasonically treated to achieve uniform doping, wherein the photoresponsive transition metal oxide exhibits a uniform elemental distribution across the cross-section of the composite film.

[0009] Furthermore, the ultrasonic treatment following mixing to achieve uniform doping includes: The ultrasonic treatment of the mixed dispersion is adapted to the required time for uniform mixing. Based on the elemental distribution of the composite film cross-section, determine whether the photoresponsive transition metal oxide doping is uniform.

[0010] Furthermore, the composite membrane prepared by the film-forming process includes: A flexible self-supporting membrane is obtained by vacuum filtration using a filter medium with porous support characteristics that is adapted to the membrane formation requirements. If a microfluidic continuous film formation process is used, the composite membrane is obtained by injecting the mixed dispersion into a microchannel and forming it in a coagulation bath.

[0011] Furthermore, placing the composite membrane in an electrolyte solution environment allows for the independent generation of photoinduced ion currents, including: The composite membrane is cut into a pre-defined size and fixed in an electrochemical cell filled with electrolyte solutions of equal concentration on both sides using a clamping structure with a reserved ion transport channel in the middle. Insert reference electrodes on both sides and connect a picoammeter; After recording the baseline ion current in the absence of light, illumination is applied to generate the light-induced ion current that is linearly related to the light intensity, wherein no external bias voltage is required. Based on the symmetry of the ion current-voltage curve of the composite membrane in an electrolyte solution of equal concentration about the origin, it is determined that ion transport has no preferential orientation, generating a pure light-induced net ion current. This pure light-induced net ion current is the ion current after excluding the baseline ion current measured under conditions of no light and an electrolyte solution of equal concentration. The generation of this light-induced ion current can operate independently.

[0012] Furthermore, the step of placing the composite membrane in an electrolyte solution environment, and converting osmotic energy into electrical energy based on the concentration gradient, includes: The composite membrane is placed between electrolyte solutions with a concentration gradient on both sides; Osmotic potential and output power are generated by ion selective transport driven by the concentration gradient in the absence of light. After being exposed to light, the surface temperature of the composite film increases through the photothermal effect, thereby enhancing the selective transport of ions and increasing the output power density. Illumination can be used as the measured signal or as an enhancement means to increase the output power of the permeation energy under different operating conditions, and the conversion of permeation energy into electrical energy can be carried out independently.

[0013] Furthermore, the real-time acquisition of output power-related data during the permeation energy conversion process includes: During the permeation energy conversion process, the potential difference and ion current data across the composite membrane are continuously collected through the electrode system and detection equipment. Based on the collected potential difference and ion current data, the corresponding output power data is calculated in real time.

[0014] Furthermore, the real-time analysis of the permeability conversion performance includes: The output power data calculated in real time is compared with the performance evaluation criteria set based on the application scenario requirements of permeable energy conversion. The performance evaluation criteria include at least the power density stability threshold and the response consistency index. Based on the comparison results, the stability and quality level of the permeation energy conversion performance can be determined in real time. If an abnormality is detected, a light enhancement mechanism can be triggered or the electrolyte solution concentration gradient can be adjusted to optimize the osmotic energy conversion performance.

[0015] Furthermore, the natural nanofibers include cotton nanofibers, wood nanofibers, or bamboo nanofibers, and the photoresponsive transition metal oxide is manganese dioxide.

[0016] Furthermore, the electrolyte solution includes potassium chloride, sodium chloride, lithium chloride, magnesium chloride, or calcium chloride solution.

[0017] Compared with the prior art, the present invention can achieve the following beneficial effects: This invention discloses a real-time analysis method for permeation energy conversion performance. Addressing the pain points of existing technologies, such as reliance on external power sources for photoelectric detection, low permeation energy conversion efficiency, and complex and difficult-to-integrate photothermal auxiliary mechanisms, this method uniformly loads photoresponsive manganese dioxide onto a three-dimensional network framework of natural nanofibers. Vacuum filtration and self-assembly form a flexible heterostructure membrane. Under no external voltage conditions, photogenerated charges drive ion directional migration to achieve linear light intensity sensing. Simultaneously, illumination is superimposed on the concentration gradient-driven permeation energy to further enhance ion diffusion current and output power density. The response is rapid, reversible, and cyclically stable. This method uses green and low-cost materials, has a simple and scalable fabrication process, and successfully integrates photodetection and energy harvesting functions into a single device. This significantly improves energy utilization efficiency and environmental adaptability in environments with abundant marine salinity gradients and sunlight, providing a highly efficient integrated solution for self-driven sensing and blue energy development. Attached Figure Description

[0018] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments and descriptions of the invention are used to explain the invention and do not constitute an undue limitation of the invention. In the drawings: Figure 1 This is a flowchart of the real-time analysis method for the permeation energy conversion performance of the present invention.

[0019] Figure 2 This is an optical photograph of the cotton nanofiber composite membrane of the present invention.

[0020] Figure 3 This is an image showing the distribution of manganese in the cross-section of the cotton nanofiber composite membrane of the present invention.

[0021] Figure 4 This is the absorption spectrum of the cotton nanofiber composite membrane of the present invention.

[0022] Figure 5 This is an IV curve of the cotton nanofiber composite membrane of the present invention in a 0.1M potassium chloride solution.

[0023] Figure 6 The photoresponse ion current diagram of the cotton nanofiber composite membrane of the present invention in 0.1M potassium chloride solution is shown.

[0024] Figure 7 The light intensity-ion current curve of the cotton nanofiber composite membrane of the present invention (the solution is 0.1M potassium chloride).

[0025] Figure 8 The diagram shows the permeation energy conversion performance of the cotton nanofiber composite membrane under different concentration gradients of the present invention (the low concentration side solution is 0.01M sodium chloride).

[0026] Figure 9 The diagram shows the permeation energy conversion performance of the cotton nanofiber composite membrane under light-induced conditions according to the present invention (concentration gradient of 50 times (0.01M:0.5M) sodium chloride). Detailed Implementation

[0027] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described herein are only for explaining the invention and do not constitute a limitation thereof. Similar elements in different embodiments are referred to by associated similar element reference numerals. In the following embodiments, many details are described to facilitate a better understanding of the invention. However, those skilled in the art will readily recognize that some features may be omitted in different situations, or may be replaced by other elements, materials, or methods. In some cases, some operations related to the invention are not shown or described in the specification. This is to avoid obscuring the core parts of the invention with excessive description. For those skilled in the art, detailed description of these related operations is not necessary; they can fully understand the related operations based on the description in the specification and general technical knowledge in the art.

[0028] It should be noted that, unless otherwise specified, the embodiments and features described in this invention can be combined to form various implementations. Furthermore, the order of the steps or actions in the method description can be changed or adjusted in a manner readily apparent to those skilled in the art. Therefore, the various orders in the specification and drawings are merely for the clear description of a particular embodiment and do not imply a mandatory order, unless otherwise stated that a particular order must be followed.

[0029] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," and "counterclockwise," etc., indicating orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation on this invention. The term "based on" should be understood as "at least partially based on." Furthermore, the terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, features defined with "first," "second," etc., may explicitly or implicitly include one or more of that feature. In the description of this invention, unless otherwise stated, "a plurality of" means two or more, and the term "including" means "including but not limited to." Various embodiments of the present invention may exist in the form of a range; it should be understood that the description in the form of a range is merely for convenience and brevity and should not be construed as a rigid limitation on the scope of the invention; therefore, it should be considered that the range description has specifically disclosed all possible sub-ranges and single numerical values ​​within that range; for example, it should be considered that the range description from 1 to 6 has specifically disclosed sub-ranges, such as from 1 to 3, from 1 to 4, from 1 to 5, from 2 to 4, from 2 to 6, from 3 to 6, etc., and single numbers within the range, such as 1, 2, 3, 4, 5, and 6, regardless of the range. Furthermore, whenever a numerical range is referred to herein, it means including any referenced number (fraction or integer) within the range referred to.

[0030] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art will understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0031] The invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0032] like Figure 1 The real-time analysis method for permeability conversion performance in this embodiment may specifically include: Step S1 involves preparing cotton nanofiber dispersions and manganese dioxide dispersions to lay the foundation for the subsequent formation of the composite membrane. The specific preparation process includes dispersing cotton nanofibers in deionized water to form a dispersion with a concentration of 0.5 to 5 mg / mL, and simultaneously dispersing manganese dioxide in deionized water to form a dispersion with a concentration of 0.5 to 2 mg / mL. During the preparation process, both dispersions are homogenized using a magnetic stirrer for approximately 30 minutes to ensure sufficient dispersion of the materials in the solution and prevent agglomeration. It should be noted that cotton nanofibers, as the matrix material, provide good mechanical support due to their natural fibrous structure, while manganese dioxide, as a functional dopant, imparts photoresponse properties to the composite membrane, such as its light absorption capacity. Figure 4 As shown.

[0033] When preparing the cotton nanofiber dispersion, a solution with a concentration of 2 mg / mL can be used. The solution should be stirred at 500 rpm for 30 minutes using a magnetic stirrer to ensure uniform fiber distribution in deionized water. Similarly, the concentration of the manganese dioxide dispersion can be set to 1 mg / mL, with the same stirring conditions as the cotton nanofiber dispersion. This combination of concentration and stirring conditions ensures the homogeneity of the two materials during subsequent mixing, thus guaranteeing the performance of the composite membrane.

[0034] Step S2 involves mixing the cotton nanofiber dispersion and the manganese dioxide dispersion in a specific ratio, followed by ultrasonic treatment to achieve uniform doping. The specific mixing ratio is 50 mg of cotton nanofiber and 7.5 mg of manganese dioxide. The two dispersions are poured into the same container and then treated with an ultrasonic device for 30 minutes to ensure complete fusion of the two materials at the microscale. Ultrasonic treatment effectively breaks up material agglomeration, allowing manganese dioxide particles to be uniformly distributed within the framework structure of the cotton nanofibers, providing a good material basis for subsequent film formation.

[0035] In one possible implementation, the mixing process can be conducted in a laboratory environment using an ultrasonic cleaner at a power setting of 200 watts and a frequency of 40 kHz for 30 minutes. After mixing, the solution state can be observed under a microscope to ensure no obvious particle deposition or stratification. This treatment method ensures a tight bond between the manganese dioxide particles and the cotton nanofibers, laying the foundation for the photoresponse characteristics and mechanical properties of the composite membrane.

[0036] Step S3 involves preparing a composite membrane from the mixed dispersion using vacuum filtration, followed by drying and heat treatment to improve membrane performance. The specific preparation process includes pouring the uniformly mixed dispersion into a vacuum filtration device. A 500 mL filtration flask is used, equipped with a 180 W vacuum pump with a maximum vacuum of 0.098 MPa. The filter medium is a 47 mm diameter polycarbonate membrane with a 200 nm pore size, and the filtration time is controlled between 12 and 24 hours. After filtration, the resulting wet membrane is placed in a drying environment and then transferred to a 60°C oven for heat treatment for 8 hours to remove residual moisture and enhance its mechanical strength. The treated composite membrane can be peeled off from the polycarbonate membrane to form an independent membrane, such as... Figure 2 As shown.

[0037] In one embodiment, the filtration process can be divided into two stages. The initial filtration time is set to 6 hours, using a lower vacuum level to avoid the membrane layer forming too quickly and causing structural inhomogeneity. The subsequent filtration time is 12 hours, gradually increasing the vacuum level to its maximum value to ensure uniform and dense membrane thickness. After filtration, the wet membrane can be naturally dried at room temperature for 2 hours before being placed in an oven for heat treatment. During heat treatment, the temperature needs to be slowly raised to 60 degrees Celsius to avoid membrane cracking due to excessive temperature difference. This staged filtration and heat treatment process can significantly improve the structural stability and mechanical flexibility of the composite membrane.

[0038] In another embodiment, for large-scale preparation needs, a continuous production method can be used instead of the traditional vacuum filtration method. For example, by designing a microfluidic device, the mixed dispersion is injected into a microchannel, with a coagulation bath connected to the end of the channel. The dispersion gradually forms a film during the flow, and then the film-forming material is collected by a roller. This method enables the continuous preparation of composite membranes and is suitable for industrial production scenarios. Specifically, the microfluidic device can be designed with a channel width of 1 mm and a length of 50 cm, and the flow rate of the dispersion is controlled at 1 ml per minute to ensure a stable film-forming process.

[0039] It should be noted that the parameters and equipment configuration in the above preparation process are not fixed and can be adjusted according to actual production conditions. For example, the filtration time can be appropriately extended or shortened according to the concentration and volume of the dispersion, and the heat treatment temperature can also be optimized and adjusted according to the temperature resistance of the membrane material. This flexibility can adapt to the needs of different application scenarios and ensure that the composite membrane maintains stable performance in various environments.

[0040] In one possible implementation, for specific applications such as integrating composite membranes into flexible electronic devices, auxiliary materials can be added during the filtration process to further enhance the membrane's flexibility. For example, a small amount of polyvinyl alcohol solution (0.1 mg / mL) can be added to the mixed dispersion before filtration, and the mixture is stirred thoroughly before filtration. The addition of polyvinyl alcohol enhances the membrane's toughness, making it less prone to breakage when bent or stretched, which is suitable for the fabrication of wearable devices or flexible sensors.

[0041] In another embodiment, depending on the choice of different matrix materials, cotton nanofibers can be replaced with wood nanofibers or bamboo nanofibers as the framework material of the composite membrane. The specific preparation process is similar to that of cotton nanofibers; the concentration of the wood nanofiber dispersion can be set to 3 mg / mL, the concentration of the manganese dioxide dispersion remains constant at 1 mg / mL, and the mixing ratio is adjusted to 60 mg of wood nanofibers and 8 mg of manganese dioxide. The filtration and heat treatment conditions are the same as in the aforementioned embodiment. This material substitution can adjust the mechanical properties and cost of the composite membrane while maintaining its photoresponse characteristics, adapting to different application requirements.

[0042] In one possible implementation, the thickness of the composite membrane can be controlled by adjusting the volume of the dispersion during filtration. For example, to prepare a thinner composite membrane, the total volume of the dispersion can be controlled at 50 ml, and the filtration time shortened to 10 hours; to prepare a thicker composite membrane, the total volume of the dispersion can be increased to 100 ml, and the filtration time extended to 20 hours. Composite membranes of different thicknesses can be applied to different scenarios. Thin films are suitable for scenarios with high response speed requirements in light intensity detection, while thick films are suitable for scenarios with high output power requirements in permeation energy conversion.

[0043] It should be noted that each step in the above preparation process requires strict control of environmental conditions to avoid the influence of external impurities on the performance of the composite membrane. For example, the filtration equipment must be operated in a dust-free environment, and high-purity deionized water must be used in the dispersion preparation and mixing processes to ensure the purity and uniformity of the membrane material. In addition, the oven temperature must be checked regularly during the heat treatment process to avoid overheating that could lead to membrane material degradation.

[0044] In one embodiment, to test the structural uniformity of the composite membrane, after filtration and heat treatment, a scanning electron microscope can be used to observe the surface and cross-section of the membrane to analyze the distribution of manganese dioxide particles within the cotton nanofiber framework. Ideally, the manganese dioxide particles should be uniformly distributed within the fiber framework, and the cross-sectional elemental distribution map should show no obvious aggregation of manganese elements. Figure 3 As shown in the figure. This uniform structural distribution is an important guarantee for the composite membrane to achieve the functions of light intensity detection and permeation energy conversion.

[0045] In another embodiment, for testing the mechanical properties of the composite membrane, after heat treatment, the membrane material can be cut into strips with a length of 20 mm and a width of 5 mm. A tensile test is then performed using a universal testing machine, and the tensile strength and elongation at break of the membrane are recorded. The test results can serve as a basis for subsequent optimization of the preparation process. For example, if the tensile strength is insufficient, the heat treatment time can be appropriately increased or the ratio of cotton nanofibers to manganese dioxide can be adjusted.

[0046] In one possible implementation, the efficiency of composite membrane fabrication can be improved by optimizing the configuration of the filtration equipment. For example, increasing the filtration flask capacity to 1000 ml, increasing the vacuum pump power to 250 watts, and using a multi-layer filter media stacking method can shorten the filtration time to 8 hours. This equipment optimization can significantly improve fabrication efficiency and is suitable for mass production scenarios.

[0047] It should be noted that the various preparation parameters and equipment configurations mentioned in the above embodiments are all based on laboratory conditions and small-scale production design. In actual industrial applications, the process flow and equipment selection can be further adjusted according to production scale and cost requirements. For example, an automated control system can be introduced to achieve fully unmanned operation of dispersion mixing, filtration, and heat treatment, thereby improving production efficiency and product consistency.

[0048] In one embodiment, to assess the stability of the composite membrane under different humidity environments, after heat treatment, the membrane material can be subjected to long-term placement tests under different relative humidity conditions. For example, the membrane can be placed in environments with relative humidity of 30%, 60%, and 90% for 7 days, followed by testing of the membrane's mechanical properties and photoresponse characteristics. The test results can be used to evaluate the suitability of the composite membrane in humid environments or liquid systems, providing data support for subsequent application design.

[0049] In another embodiment, for durability testing of the composite membrane, after preparation, the membrane material is repeatedly immersed in deionized water for 24 hours each time, repeated 5 times, and then the structural integrity and performance changes of the membrane are observed. Ideally, the composite membrane should maintain structural stability, with no manganese dioxide particles detaching and no significant attenuation in photoresponse characteristics. This durability test can verify the reliability of the composite membrane in long-term use.

[0050] In one possible implementation, cost control in the preparation of composite membranes can be achieved by optimizing material sources and process flows. For example, lower-cost bamboo nanofibers can be used as the matrix material to replace cotton nanofibers, while the amount of manganese dioxide is reduced to 5 mg, and the mixing ratio is adjusted to 50 mg bamboo nanofibers and 5 mg manganese dioxide. The filtration time is shortened to 10 hours, the heat treatment temperature is reduced to 50 degrees Celsius, and the time is shortened to 6 hours. This cost-optimized preparation method can significantly reduce production costs while ensuring basic performance, making it suitable for large-scale commercial applications.

[0051] It should be noted that each step and parameter adjustment in the above preparation process must be weighed in light of the actual application requirements. For example, in light intensity detection applications, priority should be given to ensuring the photoresponse sensitivity of the composite membrane, and the manganese dioxide doping ratio can be appropriately increased; while in permeation energy conversion applications, priority should be given to ensuring the mechanical strength and ion transport performance of the membrane, and the proportion of cotton nanofibers can be appropriately increased or the heat treatment time can be extended.

[0052] In one embodiment, to assess the performance of the composite membrane under different temperature environments, the membrane material can be tested under various temperature conditions after preparation. For example, the membrane can be placed in environments at 0 degrees Celsius, 25 degrees Celsius, and 50 degrees Celsius to test its mechanical properties and light response characteristics. The test results can be used to evaluate the suitability of the composite membrane in extreme environments, such as energy conversion in low-temperature seawater environments or light intensity detection in high-temperature and humid environments.

[0053] In another embodiment, to meet the size customization requirements of the composite membrane, the size and shape of the filter medium can be adjusted during the filtration process. For example, if a larger area composite membrane is required, a 100 mm diameter polycarbonate film can be used as the filter medium, correspondingly increasing the volume of the dispersion to 200 ml and extending the filtration time to 30 hours. If a membrane of a specific shape is required, a mold, such as a circular or rectangular mold, can be pre-designed on the filter medium to ensure that the membrane material is formed according to the predetermined shape. This customization of size and shape can meet the needs of different application scenarios, such as integrating small-sized membranes in small sensors or using large-area membranes in energy harvesting devices.

[0054] In one possible implementation, to optimize the surface smoothness of the composite membrane, an auxiliary smoothing step can be introduced during the filtration process. For example, in the initial stage of filtration, after the membrane layer has initially formed, the filtration operation is paused, and a smoothing tool is used to lightly flatten the membrane surface before filtration continues until completion. This surface smoothing treatment can reduce microscopic defects on the membrane surface and improve the uniformity of the membrane's response in light intensity detection.

[0055] It should be noted that the various preparation methods and parameter adjustments mentioned in the above embodiments are all intended to provide diverse implementation paths for the practical application of composite membranes. Whether it is small-scale preparation in the laboratory or large-scale industrial production, appropriate process flows and equipment configurations can be selected according to specific needs to ensure the excellent performance of composite membranes in light intensity detection and permeation energy conversion functions.

[0056] In one embodiment, a multi-point sampling and testing method can be introduced for quality control during the preparation of the composite membrane. For example, after filtration, small samples are cut from different locations on the membrane and subjected to microscopic observation and elemental distribution analysis to ensure the uniform distribution of manganese dioxide particles throughout the membrane layer. If uneven distribution is found in local areas, the ultrasonic treatment time or mixing ratio can be adjusted, and the dispersion can be prepared again. This quality control method can effectively improve the performance consistency of the composite membrane.

[0057] In another embodiment, to ensure the storage stability of the composite membrane, the membrane material can be sealed and stored in a dry environment after heat treatment to prevent contact with moisture or impurities in the air. Specific storage conditions include a temperature of 25 degrees Celsius and a relative humidity below 40%. A well-sealed plastic box should be used as the storage container, and a desiccant should be placed inside. After long-term storage, the membrane's performance can be periodically monitored to ensure its stability before practical application.

[0058] In one possible implementation, to address the environmental adaptability of the composite membrane preparation, preparation experiments can be conducted under different climatic conditions. For example, when preparing in high-humidity areas, a dehumidification device can be installed around the filtration equipment to ensure that the ambient humidity is below 60%; when preparing in low-temperature areas, a preheating step can be added to the heat treatment equipment to prevent stress cracking of the membrane material due to excessive temperature differences. This adjustment of environmental adaptability can ensure the stability of the composite membrane preparation process.

[0059] Step S4 involves cutting the prepared cotton nanofiber composite membrane to a specific size and configuring a clamping structure to prepare for subsequent light intensity detection and permeation energy conversion function testing. The specific cutting size is a small square of 3 mm by 3 mm to ensure a suitable membrane area for easy installation and operation in the testing device. After cutting, the composite membrane is clamped between two silicon wafers, with a small hole of 0.03 square millimeters pre-drilled in the center of each wafer for the formation of ion transport channels. During clamping, it is crucial to ensure a tight fit between the composite membrane and the silicon wafers to prevent displacement or deformation of the membrane during testing.

[0060] In one embodiment, the cutting process can use precision cutting tools, such as a high-precision laser cutter, to ensure that the edges of the film are smooth and burr-free. The cut composite film must be placed in a dust-free environment to prevent surface adsorption of impurities. During clamping, the openings on the silicon wafer must be aligned with the center of the composite film; microscopy can be used to assist in positioning to ensure the accuracy of the ion transport channels. This operation ensures the stability of the ion current in subsequent tests.

[0061] In one possible implementation, the size of the composite film can be adjusted to meet different testing requirements. For example, if light intensity detection is needed in a small portable device, the film can be cut to a small size of 2 mm by 2 mm; if it is needed for use in a larger-scale energy conversion device, the film can be cut to a size of 5 mm by 5 mm. The opening area of ​​the silicon wafer also needs to be adjusted accordingly; for example, the opening area corresponding to the small-sized film is 0.02 square millimeters, and the opening area corresponding to the large-sized film is 0.05 square millimeters. This size adjustment can adapt to the actual needs of different application scenarios.

[0062] Step S5: Place the clamped composite membrane in the electrochemical cell, and configure the electrolyte solution and electrode system to provide a testing environment for the light intensity detection function. The specific configuration process includes fixing the clamping structure in the middle of the electrochemical cell, adding electrolyte solutions of equal concentration to both sides of the cell (potassium chloride, sodium chloride, or lithium chloride can be selected), and controlling the concentration at 0.1 mol / L. Insert silver chloride electrodes into the solutions on both sides, with an electrode spacing of approximately 1 cm. The electrodes are connected to a picoammeter via wires to record changes in ion current. A bias voltage from -0.2V to 0.2V is applied to measure the IV curve, with a step voltage of 0.02V. The measured IV curve is shown below. Figure 5 As shown.

[0063] In one embodiment, the electrolyte solution can be a potassium chloride solution with a concentration of 0.1 mol / L and a volume of 50 mL on each side to ensure a balanced solution volume on both sides of the composite membrane. When inserting the electrodes, their positions must be fixed to avoid current signal fluctuations caused by electrode movement during testing. The picoammeter's range needs to be adjusted to the microampere level to accommodate minute changes in the photoinduced ion current. This configuration ensures the sensitivity and accuracy of light intensity detection.

[0064] In one possible implementation, the effects of sodium chloride and lithium chloride solutions on light intensity detection can be tested separately for different electrolyte solutions. For example, when using a 0.1 mol / L sodium chloride solution, the change in ion current of the composite membrane under light irradiation is recorded; then, the test is repeated with a lithium chloride solution of the same concentration. By comparing the current response characteristics under different solution conditions, the most suitable electrolyte type for light intensity detection can be selected. This comparative test can provide data support for solution selection in practical applications.

[0065] Step S6 involves performing a light intensity detection process. This involves applying light and recording changes in the ion current to quantitatively detect the light intensity. The specific detection process includes first testing the initial ion current of the composite membrane under no-light conditions as a reference value for calibration. Then, simulated sunlight is applied, and the changes in the light-induced ion current generated by the composite membrane are observed and recorded. Figure 6 As shown, after the light disappears, the ion current should return to its initial level, exhibiting a periodic response characteristic. The entire detection process requires no external voltage and can be completed solely based on the photoresponse characteristics of the composite membrane itself.

[0066] In one embodiment, light intensity detection can use a simulated solar light source, with the intensity controlled at 100 milliwatts per square centimeter, for 30 seconds. The light source is then turned off, and the change in ion current from its initial value to its peak and back to its initial value is recorded. The test environment must maintain a stable temperature of 25 degrees Celsius to avoid the influence of temperature fluctuations on the ion current. The picoammeter must record the current data in real time, sampling once per second to ensure that details of current changes are captured. Such test conditions can accurately reflect the composite membrane's response characteristics to light.

[0067] In one possible implementation, multiple light intensity gradients can be set for testing to meet different light intensity requirements. For example, simulated sunlight of 50 mW / cm², 100 mW / cm², and 200 mW / cm² can be applied respectively, and the changes in ion current of the composite film under different intensities can be recorded. By analyzing the correspondence between the current value and the light intensity, a linear response curve can be plotted. Figure 7 This data is used for calibration in subsequent quantitative light intensity detection. Significant differences in ion current induced under different light intensities were observed, and the ion current was linearly correlated with the light intensity. When the light stimulus disappeared, the ion current gradually returned to its initial level, indicating that the composite membrane can produce a periodic response to light intensity. This multi-gradient test verifies the applicability of the composite membrane under a wide range of light intensity conditions.

[0068] It should be noted that the uniformity of the light source must be ensured during light intensity detection to avoid distortion of ion current data due to uneven local illumination. For example, a light-diffusing plate can be added between the light source and the composite membrane to ensure uniform light distribution on the membrane surface. In addition, the testing environment should be free from external light interference. A light shield can be placed outside the electrochemical cell to allow simulated sunlight to shine onto the composite membrane only through a specific window.

[0069] In one embodiment, the periodic response capability of light intensity detection can be tested by performing multiple light-on-off cycle tests. For example, the illumination time is set to 30 seconds, the light source is turned off for 30 seconds, and the cycle is repeated 10 times, recording the rise and recovery of the ion current in each cycle. Ideally, the ion current of the composite membrane should rise rapidly after each illumination and quickly recover to its initial value after the illumination disappears, demonstrating good repeatability. This cyclic test can verify the stability of the composite membrane during long-term use.

[0070] In one possible implementation, to test the performance of light intensity detection under different ambient humidity levels, the electrochemical cell can be placed under varying humidity conditions. For example, light irradiation tests can be conducted in environments with relative humidity of 40%, 60%, and 80%, respectively, and the changes in ion current characteristics can be recorded. Humidity variations may affect the ion transport efficiency of the electrolyte solution. By comparing the test results, the suitability of the composite membrane in humid environments can be evaluated, providing a reference for its deployment in practical applications.

[0071] Step S7 involves configuring an asymmetric concentration electrolyte solution and testing the permeation energy conversion function of the composite membrane to achieve energy output based on a concentration gradient. The specific configuration process includes adding electrolyte solutions of different concentrations to both sides of the electrochemical cell. The solution type can be sodium chloride, potassium chloride, or lithium chloride, and the concentration gradient can be set to 5, 50, or 500 times. For example, the low-concentration side solution concentration is 0.01 mol / L, and the high-concentration side solution concentration is 0.5 mol / L, forming a 50-fold concentration gradient. Driven by the concentration gradient, the composite membrane generates an ion diffusion current, thereby achieving energy output. The output power density increases with increasing concentration gradient.

[0072] In one embodiment, a sodium chloride solution can be used for the osmotic energy conversion test, with a concentration gradient of 50 times. The low concentration side is 0.01 mol / L, and the high concentration side is 0.5 mol / L, with a solution volume of 50 ml on each side. During the test, the potential difference and ion current values ​​on both sides of the composite membrane are recorded, and the power density is calculated. The ambient temperature is controlled at 25 degrees Celsius to ensure the stability of the test conditions. The test results show that at a concentration gradient of 50 times, the power density can reach 9.41 W / m², calculated using the formula P=V*I / A, where P is the power density, V is the potential difference (e.g., 0.15 volts), I is the ion current (e.g., 0.0627 amperes), and A is the membrane area (e.g., 0.01 m²), demonstrating the high efficiency of the composite membrane in energy conversion. In one possible implementation, multiple gradient conditions can be set for comparative testing of energy output performance under different concentration gradients. For example, potassium chloride solutions with concentration gradients of 5x, 50x, and 500x can be prepared, and the potential difference and ion current values ​​of the composite membrane under each condition can be recorded. At a 5x concentration gradient, the power density is approximately 1 watt per square meter; at a 500x concentration gradient, the power density can be increased to 18.65 watts per square meter. The permeation energy conversion performance under different concentration gradients is as follows: Figure 8 As shown. By comparing the output performance under different gradients, the most suitable concentration configuration for practical applications can be determined.

[0073] It is important to note that the concentration of the electrolyte solution must be precisely controlled during osmotic energy conversion testing to avoid deviations in test results due to concentration errors. For example, a high-precision pipette can be used to prepare the solution to ensure that the concentration ratio of the low-concentration side to the high-concentration side matches the set value. Furthermore, the solution should be stirred periodically during the test to prevent the concentration gradient from weakening due to uneven ion diffusion.

[0074] In one embodiment, to assess the performance of osmotic energy conversion under different solution types, the energy output effects of sodium chloride, potassium chloride, and lithium chloride solutions can be tested separately. For example, a concentration gradient of 50 times and a solution volume of 50 ml on each side are set, and the power density values ​​of the composite membrane under different solution conditions are recorded. By comparing the test results, the solution type with the highest ion diffusion efficiency can be selected to optimize the energy conversion performance.

[0075] In one possible implementation, to test the application of osmotic energy conversion in a real-world environment, the concentration gradient between seawater and river water can be simulated. For example, a 0.5% sodium chloride solution can be prepared on the high-concentration side to simulate a seawater environment, and a 0.01% sodium chloride solution on the low-concentration side to simulate a river water environment, creating a concentration gradient of approximately 50 times. The energy output performance of the composite membrane under these conditions is tested, and the potential difference and ion current values ​​are recorded. This test can verify the energy harvesting capability of the composite membrane in a natural environment.

[0076] Step S8: Apply illumination to enhance the output efficiency of permeation energy conversion and test the energy conversion performance improvement effect of the composite membrane under illumination conditions. The specific testing process includes applying simulated sunlight irradiation on top of the permeation energy conversion, with the light intensity controlled at 220 milliwatts per square centimeter, and recording the changes in potential difference and ion current of the composite membrane under illumination conditions. Illumination increases the surface temperature of the composite membrane through the photothermal effect, thereby promoting the ion diffusion process and improving energy output efficiency. For example, at a 50-fold concentration gradient, the power density can be increased from 9.41 watts per square meter to 13.64 watts per square meter after adding illumination. The permeation energy conversion performance promoted by illumination is as follows: Figure 9 As shown.

[0077] In one embodiment, the light-enhanced test can use a sodium chloride solution with a concentration gradient of 50 times, a light intensity of 220 milliwatts per square centimeter, and an irradiation time of 30 minutes. During the test, the changes in ion current and potential difference of the composite membrane before and after light irradiation are recorded, and the power density increase is calculated. The ambient temperature is controlled at 25 degrees Celsius to avoid temperature interference with the test results. The test results show that the energy output efficiency under light conditions is significantly higher than that under no-light conditions, demonstrating the superior performance of the composite membrane under light-enhanced conditions.

[0078] In one possible implementation, multiple light intensity gradients can be set up for testing to assess the enhancement effect of different light intensities. For example, light intensity of 100 mW / cm², 220 mW / cm², and 300 mW / cm² can be applied respectively, and the energy output change of the composite film under a 50-fold concentration gradient can be recorded. By comparing the power density values ​​under different light intensities, the influence of light on energy conversion efficiency can be determined, providing a basis for optimizing lighting conditions in practical applications.

[0079] It is important to note that the stability of the light source must be ensured during illumination enhancement testing to avoid the impact of light intensity fluctuations on the test results. For example, a constant light source device can be used, and the light intensity should be calibrated regularly to ensure consistent test conditions. Furthermore, overheating of the electrochemical cell must be avoided during illumination; a heat dissipation device can be installed externally to maintain a stable temperature.

[0080] In one embodiment, a long-term illumination test can be conducted to assess the long-term stability of the light enhancement effect. For example, the illumination intensity is set to 220 milliwatts per square centimeter, and continuous irradiation is performed for 2 hours, recording the energy output change of the composite film under a 50-fold concentration gradient. Ideally, the power density should increase rapidly in the initial stage of illumination and remain stable after prolonged irradiation, demonstrating the composite film's continuous response to light. This test can verify the durability of the composite film in practical applications.

[0081] In one possible implementation, the light enhancement effect can be tested at concentration gradients of 5x, 50x, and 500x, respectively. For example, at a concentration gradient of 5x, 220 mW / cm² of light is applied, and the power density increase is recorded; the test is then repeated at concentration gradients of 50x and 500x. By comparing the light enhancement effect at different gradients, the suitability of the composite film under various conditions can be evaluated.

[0082] In one embodiment, to assess the performance of the light enhancement effect under different ambient temperatures, the electrochemical cell can be tested under various temperature conditions. For example, 220 milliwatts per square centimeter of light can be applied at 15°C, 25°C, and 35°C, respectively, and the energy output change of the composite membrane under a 50-fold concentration gradient can be recorded. Temperature changes may affect the ion diffusion rate and photoresponse characteristics; by comparing the test results, the performance stability of the composite membrane in different temperature environments can be evaluated.

[0083] In one possible implementation, to investigate the relationship between light enhancement effect and film thickness, composite films of different thicknesses can be fabricated and tested. For example, composite films with thicknesses of 50 micrometers, 100 micrometers, and 200 micrometers can be fabricated, and the energy output performance of each film can be recorded under a 50-fold concentration gradient and an illumination condition of 220 milliwatts per square centimeter. Thinner films may be more sensitive to light illumination, while thicker films may have an advantage in total energy output. By comparing the test results, the film thickness most suitable for light enhancement applications can be selected.

[0084] It should be noted that the effects of multiple factors, such as light intensity, concentration gradient, and environmental conditions, must be comprehensively considered during the light enhancement test to ensure the comprehensiveness and reliability of the test results. For example, changes in ambient humidity and air pressure can be recorded during the test to analyze their potential impact on energy output performance, providing data support for the application of composite membranes in complex environments.

[0085] In one embodiment, to test the application of the light enhancement effect in a real-world scenario, a test can be conducted simulating the natural environment at the junction of seawater and river water. For example, a high-concentration side solution of 0.5% sodium chloride solution and a low-concentration side solution of 0.01% sodium chloride solution are prepared, forming a concentration gradient of approximately 50 times, while simultaneously applying 220 milliwatts per square centimeter of illumination, and the energy output performance of the composite membrane is recorded. This test can verify the energy harvesting capability of the composite membrane in a natural environment, especially in sunny coastal areas.

[0086] In one possible implementation, the periodic response capability of the light-enhancing effect can be tested through multiple light-on-off cycles. For example, the illumination time is set to 30 minutes, and the light source is turned off for 30 minutes, repeated 5 times, recording the energy output change of the composite film in each cycle. Ideally, the power density should increase rapidly after each illumination and return to the no-illumination level after the illumination disappears, demonstrating good repeatability. This cyclic test can verify the photoresponse stability of the composite film during long-term use.

[0087] In one embodiment, the durability of the composite membrane under enhanced light conditions can be assessed through a long-term immersion and combined light exposure test. For example, the composite membrane is immersed in a sodium chloride solution with a 50-fold concentration gradient for 48 consecutive hours while simultaneously applying 220 milliwatts per square centimeter of light, and the changes in energy output performance are recorded. After the test, the structural integrity of the membrane is observed to ensure no significant degradation or particle shedding occurs. This test can verify the long-term reliability of the composite membrane under humid and light-exposed conditions.

[0088] In one possible implementation, to expand the application scenarios of the composite membrane under enhanced light conditions, a portable energy harvesting device can be designed. For example, the composite membrane can be integrated into a small electrochemical cell, with replaceable electrolyte solution tanks on both sides of the cell, a concentration gradient set to 50 times, and a transparent window at the top to allow light in. The device's volume is controlled to 10 cm x 10 cm x 5 cm, making it easy to carry and deploy. This portable device can be used for energy harvesting in field environments, especially in areas with abundant sunlight.

[0089] It should be noted that steps S4 to S8 primarily focus on achieving the light intensity detection and permeation energy conversion functions of the composite membrane. By optimizing test conditions and environmental configuration, the composite membrane is ensured to exhibit excellent performance in various application scenarios. Whether in laboratory testing or real-world applications, test parameters and device design can be adjusted according to specific needs to meet functional requirements in different scenarios.

[0090] It should be understood that the various forms of processes shown above can be used to reorder, add, or delete steps. For example, the steps described in this invention disclosure can be executed in parallel, sequentially, or in different orders, as long as the desired result of the technical solution disclosed in this invention can be achieved, and this is not limited herein.

[0091] The specific embodiments described above do not constitute a limitation on the scope of protection of this invention. Those skilled in the art should understand that various modifications, combinations, sub-combinations, and substitutions can be made according to design requirements and other factors. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this invention should be included within the scope of protection of this invention.

Claims

1. A real-time analysis method for permeability energy conversion performance, characterized in that, The method includes: A composite membrane was prepared by mixing a natural nanofiber dispersion with a photoresponsive transition metal oxide dispersion and then using a film-forming process. The membrane was then subjected to heat treatment to remove moisture and improve mechanical strength. When the composite membrane is placed in an electrolyte solution environment, it can independently realize the generation of photoinduced ion current or the conversion of permeation energy into electrical energy based on concentration gradient. The photoinduced ion current is linearly related to the incident light intensity and recovers the baseline after the light disappears. The permeation energy conversion power density is enhanced by light under an asymmetric concentration gradient. Real-time acquisition of output power data during the permeation energy conversion process enables real-time analysis of permeation energy conversion performance.

2. The real-time analysis method for permeability conversion performance as described in claim 1, characterized in that, The natural nanofiber dispersion is mixed with the photoresponsive transition metal oxide dispersion, comprising: Obtain the natural nanofiber dispersion and the photoresponsive transition metal oxide dispersion; The natural nanofiber dispersion and the photoresponsive transition metal oxide dispersion are mixed according to the mass ratio determined by the material properties and film formation requirements. The mixture is ultrasonically treated to achieve uniform doping, wherein the photoresponsive transition metal oxide exhibits a uniform elemental distribution across the cross-section of the composite film.

3. The real-time analysis method for permeability conversion performance as described in claim 2, characterized in that, The ultrasonic treatment following mixing to achieve uniform doping includes: The ultrasonic treatment of the mixed dispersion is adapted to the required time for uniform mixing. Based on the elemental distribution of the composite film cross-section, determine whether the photoresponsive transition metal oxide doping is uniform.

4. The real-time analysis method for permeability conversion performance as described in claim 1, characterized in that, The composite membrane prepared by the film-forming process includes: A flexible self-supporting membrane is obtained by vacuum filtration using a filter medium with porous support characteristics that is adapted to the membrane formation requirements. If a microfluidic continuous film formation process is used, the composite membrane is obtained by injecting the mixed dispersion into a microchannel and forming it in a coagulation bath.

5. The real-time analysis method for permeability conversion performance as described in claim 1, characterized in that, Placing the composite membrane in an electrolyte solution environment allows for the independent generation of photoinduced ion currents, including: The composite membrane is cut into a pre-defined size and fixed in an electrochemical cell filled with electrolyte solutions of equal concentration on both sides using a clamping structure with a reserved ion transport channel in the middle. Insert reference electrodes on both sides and connect a picoammeter; After recording the baseline ion current in the absence of light, illumination is applied to generate the light-induced ion current that is linearly related to the light intensity, wherein no external bias voltage is required. Based on the symmetry of the ion current-voltage curve of the composite membrane in an electrolyte solution of equal concentration about the origin, it is determined that ion transport has no preferred orientation, and a pure light-induced net ion current is generated. The pure light-induced net ion current is the ion current after excluding the baseline ion current measured under conditions of no light and an electrolyte of equal concentration. The generation of the light-induced ion current can operate independently.

6. The real-time analysis method for permeability conversion performance as described in claim 1, characterized in that, The step of placing the composite membrane in an electrolyte solution environment, and converting osmotic energy into electrical energy based on the concentration gradient, includes: The composite membrane is placed between electrolyte solutions with a concentration gradient on both sides; Osmotic potential and output power are generated by ion selective transport driven by the concentration gradient in the absence of light. After being exposed to light, the surface temperature of the composite film increases through the photothermal effect, thereby enhancing the selective transport of ions and increasing the output power density. Illumination can be used as the measured signal or as an enhancement means to increase the output power of the permeation energy under different operating conditions, and the conversion of permeation energy into electrical energy can be carried out independently.

7. The real-time analysis method for permeability conversion performance as described in claim 1, characterized in that, The real-time acquisition of output power-related data during the permeation energy conversion process includes: During the permeation energy conversion process, the potential difference and ion current data across the composite membrane are continuously collected through the electrode system and detection equipment. Based on the collected potential difference and ion current data, the corresponding output power data is calculated in real time.

8. The real-time analysis method for permeability conversion performance as described in claim 7, characterized in that, The real-time analysis of the completed permeability conversion performance includes: The output power data calculated in real time is compared with the performance evaluation criteria set based on the application scenario requirements of permeable energy conversion. The performance evaluation criteria include at least the power density stability threshold and the response consistency index. Based on the comparison results, the stability and quality level of the permeation energy conversion performance can be determined in real time. If an abnormality is detected, a light enhancement mechanism can be triggered or the electrolyte solution concentration gradient can be adjusted to optimize the osmotic energy conversion performance.

9. The real-time analysis method for permeability conversion performance as described in claim 1, characterized in that, The natural nanofibers include cotton nanofibers, wood nanofibers, or bamboo nanofibers, and the photoresponsive transition metal oxide is manganese dioxide.

10. The real-time analysis method for permeability conversion performance as described in claim 1, characterized in that, The electrolyte solution includes potassium chloride, sodium chloride, lithium chloride, magnesium chloride, or calcium chloride solution.

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