Preparation method of oil-water separation surface based on laser-heat treatment composite process
By employing a laser-thermal treatment composite process, an oil-water separation surface is prepared using an ultraviolet nanosecond laser and a copper foam substrate. This solves the problems of high cost, low efficiency, and pollution in existing technologies, achieving low-cost and high-efficiency preparation of oil-water separation surfaces, which is suitable for large-scale production.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- SOUTHEAST UNIV
- Filing Date
- 2023-03-06
- Publication Date
- 2026-06-12
AI Technical Summary
Existing laser-based processes for preparing oil-water separation surfaces suffer from high costs, low efficiency, and pollution problems. In particular, the use of expensive femtosecond and picosecond lasers and titanium substrates makes large-scale production difficult.
An oil-water separation surface was prepared by using a laser-thermal treatment composite process, employing an ultraviolet nanosecond laser processing system and a copper foam substrate. After forming a micro-nano structure through laser processing, the surface was subjected to low-temperature heat treatment in a drying oven.
It achieves low-cost, pollution-free, and efficient oil-water separation surface preparation, suitable for large-scale production. The foamed copper substrate is inexpensive and environmentally friendly, with a short preparation cycle, good sample separation effect, and can be reused multiple times.
Smart Images
Figure CN116352286B_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of oil-water separation surface preparation technology, and in particular to a method for preparing oil-water separation surfaces based on a laser-thermal treatment composite process. Background Technology
[0002] In recent years, marine oil spills have occurred frequently, causing serious damage to marine ecosystems. Marine oil spills are a major culprit in endangering marine life and disrupting the marine ecological balance. They not only pollute ocean waters and cause devastating damage to marine ecosystems, but also have a severe impact on the marine climate and even threaten human living environments. Furthermore, with the expansion of urbanization, the large-scale population gathering and the discharge of domestic sewage have exacerbated the environmental problems of oily wastewater, making its treatment a major concern. To address these issues, researchers are increasingly focusing on research into the separation of oil / water mixtures.
[0003] In recent years, numerous researchers have employed various methods to prepare functional surfaces with superhydrophobic and superoleophilic properties for oil-water separation. These methods include solution etching, sol-gel etching, chemical vapor deposition (CVD), electrochemical etching, template etching, and laser etching. Among these methods for preparing oil-water separation surfaces, solution etching struggles to precisely control the impact of etching time on material properties and cannot prepare superhydrophobic and superoleophilic layers on highly corrosion-resistant materials. Sol-gel and CVD methods produce hydrophobic and superoleophilic layers with poor adhesion to the substrate, limiting their application. Electrochemical etching produces hydrophobic and superoleophilic layers with poor durability, making it difficult to maintain a superhydrophobic and superoleophilic state for extended periods. Template-based superhydrophobic and superoleophilic surfaces are easily scratched and detached under impact. In contrast, laser etching is simple and reliable, allowing for the precise construction of multi-level micro / nano structures on almost any material surface simply by adjusting various process parameters. Oil-water separation surfaces prepared by laser etching are widely used in production in various fields such as industry, aerospace, and shipbuilding due to their advantages such as long-lasting stability.
[0004] However, there are still some problems with the current process of preparing oil-water separation surfaces using lasers, mainly including: 1) Most of the lasers used are femtosecond lasers and picosecond lasers, which are expensive and difficult to use for large-scale production; 2) Since most laser surface treatment processes require the use of small spot size and repeated scanning, and the prepared surface needs to be left to stand for several days to deposit hydrophobic groups to achieve superhydrophobic and superoleophilic properties, the overall preparation efficiency is low; 3) The metal foam substrates used are mostly titanium, which is expensive.
[0005] In conclusion, developing a high-efficiency, low-cost, and pollution-free oil-water separation surface preparation process is of paramount importance. Summary of the Invention
[0006] The purpose of this invention is to address the problems existing in the background technology by proposing a method for preparing oil-water separation surfaces based on a laser-thermal treatment composite process, so as to solve the problems of complex preparation process, high cost and pollution.
[0007] The technical solution of this invention, a method for preparing an oil-water separation surface based on a laser-thermal treatment composite process, includes the following specific steps:
[0008] S1. Cleaning the substrate: Ultrasonic cleaning is performed on the metal foam substrate to remove surface residues and remove moisture from the surface of the cleaned metal foam substrate to obtain a clean metal foam substrate.
[0009] S2, Laser processing: The cleaned metal foam substrate in S1 is placed on the sample stage of the ultraviolet nanosecond laser processing system, and micro-nano structures are processed on the surface of the metal foam substrate using the laser beam.
[0010] S3. Heat treatment: The metal foam substrate treated in S2 is placed in a drying oven and baked to obtain an oil-water separation surface.
[0011] Preferably, the metal foam substrate is copper foam.
[0012] Preferably, the cleaning process of the metal foam substrate in S1 includes:
[0013] The metal foam substrate was sequentially immersed in acetone, anhydrous ethanol, and deionized water for ultrasonic cleaning for 5–10 minutes each.
[0014] Preferably, in step S1, the cleaned metal foam substrate is dried by blowing with nitrogen gas or air-drying at room temperature.
[0015] Preferably, in S2: the ultraviolet nanosecond laser processing system uses an ultraviolet nanosecond pulsed laser with a wavelength of 355nm, a pulse width of 0.01μs, a pulse repetition frequency of 40kHz, a laser power of 6.5W, a pulse energy of 0.163mJ, and a power density of 0.575GW / cm². 2 The effective spot diameter after focusing is approximately 60 μm, the laser scanning rate is 50–500 mm / s, the laser beam scanning area is 25 mm × 25 mm, and the laser scanning spacing is 0.01–0.03 mm.
[0016] Preferably, in S3: the temperature of the drying oven is 150-200℃, and the heating time is 100-120 min.
[0017] Compared with the prior art, the present invention has the following beneficial technical effects:
[0018] 1) The metal foam substrate raw material used in this invention is foamed copper, which is inexpensive, readily available, non-toxic, non-polluting, will not harm the user's body, and is environmentally friendly.
[0019] 2) The operation process of this invention is simple, and the processing equipment used is a low-cost ultraviolet nanosecond laser processing system, which has a lower production cost than femtosecond lasers and picosecond lasers and is suitable for large-scale production.
[0020] 3) This invention shortens the preparation cycle, improves the preparation efficiency, achieves good oil-water separation of the sample, and can be reused multiple times. Attached Figure Description
[0021] Figure 1 This is a schematic diagram of the process flow of the present invention;
[0022] Figure 2 SEM images of surfaces prepared by different treatment methods in this invention;
[0023] Figure 3 EDS spectra of surfaces prepared by different treatment methods in this invention;
[0024] Figure 4 The graph shows the contact angle measurement results of the surface prepared by different treatment methods in this invention with water droplets.
[0025] Reference numerals: 1. Laser; 2. Attenuator; 3. Beam amplifier; 4. Galvanometer; 5. Controller; 6. Cooling system; 7. Sample; 8. Sample stage; 9. Computer; 10. Drying oven; 11. Ultrasonic cleaner. Detailed Implementation
[0026] The specific embodiments of the present invention are described below with reference to the accompanying drawings.
[0027] Please refer to Figure 1 The method for preparing the high-efficiency oil-water separation surface of this invention includes the following steps:
[0028] Step 1) Cleaning the substrate: Ultrasonic cleaning is performed on the metal foam substrate to remove surface residues and remove moisture from the surface of the cleaned metal foam substrate to obtain a clean metal foam substrate.
[0029] Step 2) Laser processing: The cleaned metal foam substrate is placed on the sample stage 8 of the ultraviolet nanosecond laser processing system, and the laser beam is used to process micro-nano structures on the surface of the metal foam substrate.
[0030] Step 3) Low-temperature heat treatment: Place the metal foam substrate treated in step 2) in a drying oven 10 and bake it to obtain an oil-water separation surface.
[0031] The metal foam substrate is copper foam.
[0032] The laser-heat treatment composite process of this invention mainly includes two process steps: laser processing and low-temperature heat treatment.
[0033] The laser processing equipment used is the MQ5T ultraviolet nanosecond laser processing platform manufactured by Guangzhou Maqing Laser Co., Ltd., and laser 1 is the Seal-355-3 / 5 ultraviolet nanosecond pulsed laser manufactured by Shenzhen JPT Optoelectronics Co., Ltd.
[0034] like Figure 1 As shown, the laser beam is emitted by laser 1, passes through attenuator 2 and beam amplifier 3, and enters galvanometer 4. Computer 9 is connected to controller 5 to control galvanometer 4, thereby controlling the scanning pattern of the laser beam. During the processing, galvanometer 4 is connected to cooling system 6.
[0035] Among them, laser 1 has a wavelength of 355nm, a pulse width of 0.01μs, a pulse repetition frequency of 40kHz, a laser power of 6.5W, a pulse energy of 0.163mJ, and a power density of 0.575GW / cm². 2 The effective spot diameter after focusing is approximately 60 μm, the laser scanning rate is 50–500 mm / s, the laser beam scanning area is 25 mm × 25 mm, and the laser scanning spacing is 0.01–0.03 mm.
[0036] The temperature of the drying oven 10 used for low-temperature heat treatment is 150-200℃, and the heating time is 100-120 min.
[0037] The following specific embodiments further illustrate the method for preparing the high-efficiency oil-water separation surface of this application.
[0038] Example 1
[0039] A method for preparing superhydrophobic and superoleophilic oil-water separation foam copper includes the following steps:
[0040] Step 1) Cut the foamed copper substrate to a size of 10mm×10mm, and use acetone, anhydrous ethanol and deionized water to ultrasonically clean for 5 minutes each to remove contaminants from the substrate surface, and then place it in the air to air dry naturally.
[0041] Step 2) Perform laser processing on the surface using the following parameters: laser power 6.5W, scanning spacing 0.02mm, and power density 0.57GW / cm². 2 The pulse width was 0.01 μs, the pulse energy was 0.16 mJ, and the laser scanning rate was 100 mm / s. After processing, the substrate was removed. A uniform micro / nano composite structure was formed on the copper foam surface.
[0042] Step 3) Place the foamed copper processed in Step 2) into a drying oven 10 and bake it at 150℃ for 100 minutes. After taking it out, the surface contact angle with water is measured to be 151.8±0.9° and the contact angle with oil is 0°, thus obtaining a foamed copper surface with oil-water separation properties.
[0043] Example 2
[0044] A method for preparing superhydrophobic and superoleophilic oil-water separation foam copper includes the following steps:
[0045] Step 1) Cut the foamed copper substrate to a size of 15mm×15mm, and use acetone, anhydrous ethanol and deionized water to ultrasonically clean for 8 minutes each to remove contaminants from the substrate surface, and then place it in the air to air dry naturally.
[0046] Step 2) Perform laser processing on the surface using the following parameters: laser power 6.5W, scanning spacing 0.02mm, and power density 0.57GW / cm². 2 The pulse width was 0.01 μs, the pulse energy was 0.16 mJ, and the laser scanning rate was 200 mm / s. After processing, the substrate was removed. A uniform micro / nano composite structure was formed on the copper foam surface.
[0047] Step 3) Place the foamed copper processed in Step 2) into a drying oven 10 and bake it at 180℃ for 110 minutes. After taking it out, the surface contact angle with water is measured to be 153.2±1.7° and the contact angle with oil is 0°, thus obtaining a foamed copper surface with oil-water separation properties.
[0048] Example 3
[0049] A method for preparing superhydrophobic and superoleophilic oil-water separation foam copper includes the following steps:
[0050] Step 1) Cut the foamed copper substrate to a size of 20mm×20mm, and use acetone, anhydrous ethanol and deionized water to ultrasonically clean for 10 minutes each to remove contaminants from the substrate surface, and then place it in the air to air dry naturally.
[0051] Step 2) Perform laser processing on the surface using the following parameters: laser power 6.5W, scanning spacing 0.03mm, and power density 0.57GW / cm². 2 The pulse width was 0.01 μs, the pulse energy was 0.16 mJ, and the laser scanning rate was 200 mm / s. After processing, the substrate was removed. A uniform micro / nano composite structure was formed on the copper foam surface.
[0052] Step 3) Place the foamed copper processed in Step 2) into a drying oven 10 and bake it at 200℃ for 120 minutes. After taking it out, the surface contact angle with water is measured to be 155.3±1.4° and the contact angle with oil is 0°, thus obtaining a foamed copper surface with oil-water separation properties.
[0053] The following analysis examines the technical effects achieved by the preparation method of this application.
[0054] 1. In terms of surface structure, such as Figure 2 The image shows the SEM test results of the surface after laser surface treatment in this invention. Observation of SEM images at different magnifications reveals that the untreated copper framework remains intact. After laser surface treatment, submicron and nano-sized particles are distributed along the boundaries of each laser-induced microgroove. These particles are mainly formed during the interaction between the laser and the material, where localized melting, evaporation, and recasting occur on the material surface, resulting in the accumulation of molten material on the melt-fractured section, forming regular spheres. These spheres accumulate to create a rough, layered structure. Therefore, at higher magnifications, it can be observed that the framework primarily consists of multi-level micro / nano structures.
[0055] This indicates that the laser surface treatment process in this application can induce the generation of multi-level (micrometer-submicrometer-nano) micro / nano structures. According to wettability theory, surface roughness enhances surface wettability, i.e., it makes hydrophilic surfaces more hydrophilic and hydrophobic surfaces more hydrophobic. Under natural conditions, the surface energy of oil is 20–30 mN / m, and the surface energy of water is 72 mN / m. Oil droplets themselves have low surface free energy, and foamed copper consistently exhibits superoleophilicity, with an oil contact angle <10°. When the laser processing parameters reach the ablation threshold of foamed copper, the surface roughness of the foamed copper increases. Water, due to its higher surface energy, and copper foil, exhibiting a certain degree of hydrophobicity, enhance the hydrophobicity of the foamed copper. Increasing the roughness may promote superhydrophobicity, thus laying the foundation for achieving superhydrophobic properties on metal surfaces.
[0056] 2. Regarding surface chemical properties, such as Figure 3 The figure shows the chemical composition results of different surfaces obtained by EDS energy dispersive spectroscopy.
[0057] Figure 3 'a' represents the result for the untreated surface. Figure 3 As can be seen from a, a large amount of Cu and trace amounts of O elements can be detected on the untreated surface, along with a certain amount of C elements. Among them, Cu elements originate from the substrate material, O elements originate from the oxidation of the surface layer of the substrate material, and C elements originate from slight contamination on the surface of the substrate material.
[0058] Figure 3 b represents the result of laser surface treatment. (From...) Figure 3As can be seen from b, the Cu content on the surface decreases after laser surface treatment, while the C and O content increases significantly. This indicates that laser micro-nano processing not only induces the formation of micro-nano structures on the metal surface, but also causes significant oxidation of the surface, resulting in the formation of a large number of hydroxyl (-OH) and carboxyl (-COOH) groups on the surface.
[0059] Figure 3 c represents the result of laser-thermal treatment of the surface. Figure 3 It can be seen that the following two chemical changes mainly occur: First, the C element content on the laser-heat-treated surface continues to increase, while the Cu element content continues to decrease; second, the presence of Si element is detected on the laser-heat-treated surface. Among them, (1) the increase in C element content is mainly due to the low-temperature heat treatment accelerating the deposition of non-polar carbonaceous hydrophobic groups (such as -CH2-, -CH3, C=C and other functional groups) in the air on the metal surface; (2) the deposition of Si element comes from the silicone rubber door seal on the drying oven 10. During the heat treatment process at 150-200℃, silicon atoms on the silicone rubber door seal evaporate into the air and are subsequently deposited on the metal surface, forming a hydrophobic silicon-containing thin film. Both chemical changes are conducive to the formation of superhydrophobic properties on the surface: the carbonaceous water-containing groups with hydrophobic properties and the silicon-containing thin film are deposited together on the laser-heat-treated surface, promoting the formation of superhydrophobic properties on the surface.
[0060] 3. Regarding surface wettability, such as Figure 4 As shown, this is a measurement result of the contact angle of a surface prepared using different treatment methods with a water droplet.
[0061] Figure 4 Image 'a' shows the water droplet contact angle of the untreated surface. The measured water droplet contact angle is 105.4 ± 2.1°, proving that the surface has hydrophobic properties.
[0062] Figure 4 b is an image of the water droplet contact angle on the surface after laser processing. The surface contact angle was measured to be 0°, and the surface exhibited significant superhydrophilic properties. The main reasons for this phenomenon are: (1) Laser processing significantly increased the roughness of the metal surface, causing the water droplet to change from an unstable Cassie state to a saturated Wenzel state at the laser-induced microstructure composite interface; (2) Laser micro-nano processing not only induced the formation of micro-nano structures on the metal surface, but also caused significant oxidation of the surface, resulting in the formation of a large number of hydroxyl (-OH) and carboxyl (-COOH) groups. These groups are all polar groups with extremely strong hydrophilic properties.
[0063] Figure 4c is the water droplet contact angle image of the heat-treated surface, with a contact angle of 120.4 ± 1.4°. This indicates that heat treatment can improve the surface contact angle to some extent, but it is insufficient to make the surface achieve superhydrophobic properties. The main reason is that although the heat treatment process can deposit hydrophobic groups in the air onto the surface, the surface treated only lacks micro- and nano-structures, thus failing to meet the necessary conditions for achieving superhydrophobic properties.
[0064] Regarding the laser-heat treatment process used in this application ( Figure 4 d) The surface contact angle reached 155.3 ± 1.4°. This indicates that the copper foam achieved superhydrophobic properties through the combined effects of laser surface treatment and heat treatment. Laser processing induces micro / nano structures on the surface, while heat treatment alters the surface chemistry and reduces surface energy. The combined effect of the micro / nano structures and the lower surface energy ensures the surface achieves superhydrophobic properties.
[0065] 4. Regarding oil-water separation performance, when the laser processing parameters used to prepare the oil-water separation surface are a laser scanning distance of 0.02 mm and a scanning rate of 200 mm / s, the sample separation rate under these parameters is faster and the separation effect is better, with an oil-water separation ratio of over 90%.
[0066] 5. In terms of economy and use, the present invention has certain advantages.
[0067] The main advantages are: (1) The present invention uses a nanosecond laser processing platform, which is less expensive than femtosecond and picosecond laser processing platforms and can achieve large-scale preparation. (2) The copper foam substrate used is inexpensive, non-toxic, non-polluting, and will not harm the user's body, and is environmentally friendly. (3) The preparation process is simple and easy to understand, with a short preparation cycle, high preparation efficiency, good sample separation effect, and can be reused multiple times.
Claims
1. A method for preparing an oil-water separation surface based on a laser-thermal treatment composite process, characterized in that, The specific steps include the following: S1. Cleaning the substrate: The metal foam substrate is ultrasonically cleaned to remove surface residues and remove moisture from the surface of the cleaned metal foam substrate to obtain a clean metal foam substrate; the metal foam substrate is a copper foam substrate. S2, Laser processing: The cleaned metal foam substrate in S1 is placed on the sample stage of the ultraviolet nanosecond laser processing system, and micro-nano structures are processed on the surface of the metal foam substrate using the laser beam. The ultraviolet nanosecond laser processing system uses an ultraviolet nanosecond pulsed laser with a wavelength of 355 nm, a pulse width of 0.01 µs, a pulse repetition frequency of 40 kHz, a laser power of 6.5 W, a pulse energy of 0.163 mJ, and a power density of 0.575 GW / cm². 2 The effective spot diameter after focusing is 60µm, the laser scanning rate is 50~500mm / s, the laser beam scanning area is 25mm×25mm, and the laser scanning spacing is 0.01~0.03mm. S3. Heat treatment: The metal foam substrate treated in S2 is placed in a drying oven and baked at a temperature of 150~200℃ for 100~120min to obtain oil-water separation foam copper with superhydrophobic and superoleophilic properties.
2. The method for preparing an oil-water separation surface based on a laser-thermal treatment composite process according to claim 1, characterized in that, The cleaning process for the metal foam substrate in S1 includes: The metal foam substrate was sequentially immersed in acetone, anhydrous ethanol, and deionized water for ultrasonic cleaning for 5-10 minutes each.
3. The method for preparing an oil-water separation surface based on a laser-thermal treatment composite process according to claim 1, characterized in that, In S1, the cleaned metal foam substrate is dried by blowing with nitrogen gas or air-drying at room temperature.