A method for preparing a coffee grounds recycled membrane and its application
Coffee grounds recycled membranes are prepared through degreasing, dissolving, cooling, coagulation regeneration, and hot-press drying steps. By utilizing ionic liquids and metal ion solutions to form metal coordination bonds, the problems of cumbersome coffee grounds film processing and easy bacterial growth in existing technologies are solved, achieving efficient packaging and preservation effects.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- AGRI PRODS PROCESSING RES INST CHINESE ACAD OF TROPICAL AGRI SCI
- Filing Date
- 2025-09-28
- Publication Date
- 2026-05-26
AI Technical Summary
The existing technology for preparing films from coffee grounds is cumbersome, the raw materials are complex, and bacteria can easily grow under the action of water and microorganisms, affecting the safety and lifespan of the film.
Coffee grounds regenerated membranes were prepared using a process of degreasing, dissolving, cooling, coagulation regeneration, and hot-press drying. The coffee grounds were dissolved using an ionic liquid, and a metal ion solution was used as a coagulation bath to form metal coordination bonds, thereby enhancing the physical properties and antibacterial properties of the membrane.
The prepared recycled coffee grounds film exhibits good load-bearing capacity and antibacterial properties in the fields of packaging and food preservation, especially in the preservation of tropical fruits and vegetables, where it has antibacterial and antiseptic effects and extends the storage period.
Smart Images
Figure CN122080459A_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of high-value utilization and processing of waste wood fiber raw material coffee grounds, and specifically relates to a method for preparing a coffee grounds recycled membrane and its application. Background Technology
[0002] Coffee, as one of the world's most popular beverages, ranks among the top traded commodities globally. Statistics from the International Coffee Organization show that global coffee consumption in 2023 / 24 is projected to increase by 2.2% compared to 2022 / 23, reaching 177 million bags (60 kg per bag). Simultaneously, the production of coffee beverages generates a large amount of coffee grounds: approximately 650 kg of coffee grounds are produced per ton of green coffee beans, and about 2 kg of wet coffee grounds are produced per kilogram of instant coffee. Most of the coffee grounds discarded by coffee factories and coffee shops end up in landfills. However, landfilling coffee grounds produces methane, a potent greenhouse gas, whose environmental harm far exceeds that of carbon dioxide. Furthermore, harmful substances such as caffeine, tannins, and polyphenols in coffee grounds may leach into the environment, causing toxic residues, water pollution, and vegetation damage. It is worth noting that coffee grounds have a similar composition to common lignocellulosic biomass raw materials, being rich in cellulose, hemicellulose, and lignin. Developing packaging materials from waste coffee grounds not only enables the high-value utilization of coffee grounds and reduces their potential environmental pollution as waste, but also provides an innovative approach to developing sustainable lignocellulosic packaging materials.
[0003] Chinese patent CN202210853701.4, "A method for preparing a recycled composite membrane using coffee grounds," discloses a method for making a thin film using coffee grounds. However, the preparation process of this method is cumbersome, the raw materials are complex, and in the actual use of the film, bacteria can easily grow under the action of water and microorganisms, which significantly affects its safety and service life. Summary of the Invention
[0004] In view of the technical problems existing in the prior art, the purpose of this invention is to provide a method for preparing a coffee grounds regenerated membrane.
[0005] Another objective of this invention is to provide a coffee grounds regenerated membrane prepared by the above method.
[0006] Another objective of this invention is to provide the application of the above-mentioned recycled coffee grounds film in the fields of packaging and food preservation.
[0007] To achieve the above objectives, the present invention adopts the following technical solution: A method for preparing a coffee grounds recycled membrane includes the following steps: (1) Degrease and dry the coffee grounds to obtain degreased coffee grounds; (2) Dissolve the defatted coffee grounds to obtain a coffee grounds solution; (3) The coffee grounds solution is poured into a mold and cooled to obtain coffee grounds sol; (4) The coffee grounds sol was placed in a metal ion solution and coagulated and regenerated to obtain coffee grounds regenerated gel; (5) The coffee grounds regenerated gel is hot-pressed and dried to obtain a coffee grounds regenerated membrane.
[0008] Furthermore, the device used for the degreasing process in step (1) is a Soxhlet extractor.
[0009] Further, the defatting process in step (1) involves extracting coffee grounds using a solvent obtained by mixing benzene and ethanol solution, wherein the volume ratio of benzene to ethanol solution is 2:1 and the purity of ethanol solution is 95%.
[0010] Further, in step (1), the ratio of coffee grounds to benzene / ethanol solution is 1 g: 10-50 mL.
[0011] Furthermore, the degreasing treatment in step (1) takes 6-10 hours.
[0012] Further, the drying in step (1) involves drying the defatted coffee grounds to an absolutely dry state.
[0013] Further, the solvent used for dissolution in step (2) includes at least one of ionic liquid, alkaline urine solvent, and N-methylmorpholine-N-oxide (NMMO) aqueous solution.
[0014] Further, the ionic liquid includes at least one of 1-butyl-3-methylimidazolium chloride, 1-allyl-3-methylimidazolium chloride, and 1-ethyl-3-methylimidazolium acetate.
[0015] Further, in step (2), the mass ratio of defatted coffee grounds to solvent in the dissolution process is 1:10-30.
[0016] Further, the dissolution temperature in step (2) is 90-140 ℃; the time is 3-36 h; and the stirring speed during dissolution is 600-1000 rpm.
[0017] Further, the cooling in step (3) involves placing the mold containing the coffee grounds solution at 15-25 °C for cooling.
[0018] Furthermore, step (4) of placing the coffee grounds sol in a metal ion solution means placing the coffee grounds sol together with the mold in the metal ion liquid.
[0019] Further, the concentration of metal ions in the metal ion solution in step (4) is 0.05-2 mol / L.
[0020] Further, the metal ion solution in step (4) is a chloride salt solution of metal ions.
[0021] Further, the metal ions in the metal ion solution of step (4) include Cu. 2+ Zn 2+ Ca 2+ Mg 2+ Al 3+ At least one of them.
[0022] Furthermore, the solidification and regeneration in step (4) is carried out at a temperature of 15-25 °C for 6-24 h.
[0023] Furthermore, during the coagulation and regeneration process described in step (4), multiple liquid exchange operations are performed to remove the solvent added in step (2).
[0024] Further, the pressure of hot pressing drying in step (5) is 0.5-1.5 MPa; the temperature is 45-100 ℃; and the time is 3-36 h.
[0025] The coffee grounds regenerated membrane prepared by the above method.
[0026] The above-mentioned recycled coffee grounds film has applications in the packaging and food preservation fields.
[0027] Furthermore, the food preservation field is the field of tropical fruit and vegetable preservation.
[0028] Furthermore, the tropical fruits and vegetables include at least one of lychee, durian, mango, papaya, and wampee.
[0029] The inventive principle of this invention: This invention utilizes solvents such as ionic liquids to dissolve coffee grounds, breaking the original bonds of carbohydrates in the coffee grounds. Then, the grounds are placed in a coagulation bath, where the solvent is displaced and the carbohydrates reconnect, thus forming a regenerated coffee grounds membrane. Furthermore, this invention uses a metal ion solution as the regeneration coagulation bath, allowing metal ions to form a stable chemical bond with the regenerated coffee grounds gel network through coordination bonds during the coffee grounds regeneration process.
[0030] The implementation of this invention has the following beneficial effects: This invention uses a metal ion solution as a regeneration coagulation bath. The strong metal coordination bond between the metal ions and the oxygen-containing functional groups of coffee grounds molecules, along with the antibacterial properties of the metal ions themselves, endow the coffee grounds regenerated film with excellent physical and antibacterial properties. When applied in the packaging field, it has good load-bearing capacity, and when applied in the preservation field, it has good preservation effect. In particular, it plays an antibacterial and antiseptic role in the preservation of tropical fruits and vegetables that are severely affected by diseases, such as lychee, durian, mango, papaya, and wampee, thereby extending the storage period. Attached Figure Description
[0031] Figure 1 This is a flowchart illustrating the preparation method of the coffee grounds regenerated membrane of the present invention.
[0032] Figure 2 The images show the antibacterial effects of the coffee grounds regenerated membranes obtained in Examples 1-3 and the comparative examples.
[0033] Figure 3 This is a comparison chart of the spoilage rate of mangoes packaged with coffee grounds recycled film obtained in Example 3 and commercially available PE film.
[0034] Figure 4 This is a comparison image of the bacterial colonies on the surface of mangoes packaged with coffee grounds recycled film obtained in Example 3 and commercially available PE film. Detailed Implementation
[0035] The present invention will be further described in detail below with reference to embodiments and accompanying drawings, but the embodiments of the present invention are not limited thereto. Unless otherwise specified in the embodiments, conventional conditions or conditions recommended by the manufacturer shall apply. Reagents or instruments used, unless otherwise specified, are all commercially available conventional products.
[0036] Unless otherwise specified, all reagents used in the examples are commercially available.
[0037] like Figure 1 As shown, a method for preparing a coffee grounds recycled membrane includes the following steps: (1) The coffee grounds are degreased and dried to obtain degreased coffee grounds.
[0038] Specifically, the defatting device is a Soxhlet extractor; the defatting process involves extracting coffee grounds using a solvent obtained by mixing benzene and ethanol solutions; wherein the volume ratio of benzene to ethanol solution is 2:1, and the purity of the ethanol solution is 95%; the volume ratio of coffee grounds to benzene / ethanol solution is 1 g: 10-50 mL, and this volume ratio can be selected from any value within this range, preferably 1 g: 10 mL, 1 g: 20 mL, or 1 g: 50 mL; the defatting time is 6-10 h, and this processing time can be selected from any value within this range, preferably 6 h, 8 h, or 10 h; drying involves drying the defatted coffee grounds to an absolutely dry state. In this step, defatting the coffee grounds can remove resins, fats, waxes, tannins, pigments, and other substances from the coffee grounds, improving their accessibility during the dissolution process, increasing solubility, and accelerating the dissolution rate.
[0039] (2) Dissolve the defatted coffee grounds to obtain a coffee grounds solution.
[0040] Specifically, the solvent used for dissolution includes at least one of ionic liquids, alkaline urea solvents, and aqueous solutions of N-methylmorpholine-N-oxide (NMMO). Solvents of any type or combination thereof can achieve good dissolution results, preferably ionic liquids or aqueous solutions of N-methylmorpholine-N-oxide (NMMO). The ionic liquid includes at least one of 1-butyl-3-methylimidazolium chloride, 1-allyl-3-methylimidazolium chloride, and 1-ethyl-3-methylimidazolium acetate. Ionic liquids of any type or combination thereof can achieve good dissolution results, preferably 1-butyl-3-methylimidazolium chloride or 1-allyl-3-methylimidazolium chloride. The mass ratio of defatted coffee grounds to solvent in dissolution is 1:10-30, and any value can be selected within this range, preferably 1:10, 1:20, or 1:30. The dissolution temperature is 90-140 °C, and any value can be selected within this range, preferably 90 °C, 100 °C, 120 °C, or 140 °C. ℃; the time is 3-36 h, and any value can be selected within this range, preferably 3 h, 12 h, 24 h or 36 h; the stirring speed during dissolution is 600-1000 rpm, and any value can be selected within this range, preferably 600 rpm, 800 rpm or 1000 rpm. In this step, ionic liquids are used as solvents to break the complex bonds between carbohydrates and lignin in the coffee grounds, such as hydrogen bonds and covalent bonds, so as to achieve good dissolution of the coffee grounds and obtain a homogeneous dissolution solution, which is used to prepare for the regeneration process in step (4).
[0041] (3) The coffee grounds solution is poured into a mold and cooled to obtain coffee grounds sol.
[0042] Specifically, cooling involves placing the mold containing the coffee grounds solution at 15-25°C. The cooling temperature can be any value within this range, but is preferably 15°C, 20°C, or 25°C. In this step, the coffee grounds solution is initially formed into a coffee grounds sol, which facilitates better regeneration in the coagulated liquid of step (4).
[0043] (4) Place the coffee grounds sol in a metal ion solution, solidify and regenerate to obtain coffee grounds regenerated gel.
[0044] Specifically, placing coffee grounds sol in a metal ion solution involves placing the coffee grounds sol along with the mold into the metal ion liquid; the concentration of metal ions in the metal ion solution is 0.05-2 mol / L, and any value within this range can be selected, preferably 0.05 mol / L, 0.2 mol / L, 0.5 mol / L, 1 mol / L, or 2 mol / L; the metal ion solution is a chloride salt solution of metal ions; the metal ions in the metal ion solution include Cu. 2+ Zn 2+ Ca 2+ Mg 2+ Al 3+ At least one of the above-mentioned metal ions, when the metal ion is of the above type or combination, can enhance the physical properties and antibacterial properties of the coffee grounds regenerated membrane, preferably Cu. 2+ Zn 2+ Or Al 3+ The coagulation and regeneration temperature is 15-25 ℃, and any value can be selected within this range, preferably 15 ℃, 20 ℃ or 25 ℃; the time is 6-24 h, and any value can be selected within this range, preferably 6 h, 12 h or 24 h; multiple liquid changes are performed during coagulation and regeneration to remove the solvent added in step (2). In this step, a metal ion solution is used as the regeneration coagulation bath, so that the metal ions can form a stable chemical connection with the coffee grounds regenerated gel network through coordination bonds during the coffee grounds regeneration process.
[0045] (5) The coffee grounds regenerated gel is hot-pressed and dried to obtain a coffee grounds regenerated membrane.
[0046] Specifically, the hot-press drying pressure is 0.5-1.5 MPa, and any value within this range can be selected, preferably 0.5 MPa, 1 MPa, or 1.5 MPa; the temperature is 45-100 ℃, and any value within this range can be selected, preferably 45 ℃, 55 ℃, 60 ℃, 65 ℃, or 100 ℃; the time is 3-36 h, and any value within this range can be selected, preferably 3 h, 12 h, 24 h, or 36 h. In this step, hot pressing can quickly remove moisture from the coffee grounds regenerated gel and make the regenerated membrane more dense and uniform, which has a positive effect on the physical properties of the regenerated membrane.
[0047] Example 1 (1) The coffee grounds were degreased using a Soxhlet extractor. The solvent used for extraction was a benzene / ethanol solution (benzene and 95% ethanol were mixed at a volume ratio of 2:1). The ratio of coffee grounds to benzene / ethanol solution was 1:20 (w / v, g / mL), and the extraction time was 8 h. The extracted coffee grounds were air-dried and then dried in an oven at 105 ℃ until completely dry to obtain degreased coffee grounds. (2) 1 g of defatted coffee grounds were added to 1-allyl-3-methylimidazolium chloride. The mass ratio of defatted coffee grounds to 1-allyl-3-methylimidazolium chloride was 1:20. The mixture was stirred at 800 rpm at 120 °C for 24 h to dissolve the coffee grounds completely in the solvent, thus obtaining a coffee grounds solution. (3) The coffee grounds dissolved in the sol was poured into a mold and cooled at 25 °C to obtain coffee grounds sol; (4) The coffee grounds sol, together with the mold, was placed in a 0.5 mol / L AlCl3 solution at 25 °C for 24 h to solidify and regenerate. During this period, the solution was changed multiple times (the solution changed was a 0.5 mol / L AlCl3 solution) to remove 1-allyl-3-methylimidazolium chloride and obtain coffee grounds regenerated gel. (5) The coffee grounds regenerated gel was placed in a flatbed hot press for drying. The pressure was set to 1 MPa, the drying temperature was selected to be 60℃, and the drying time was 24 h, to obtain a gel loaded with Al. 3+ Coffee grounds recycled membrane.
[0048] Example 2 The difference between this embodiment and Embodiment 1 is that the 0.5 mol / L AlCl3 solution in step (4) is replaced with a 0.5 mol / L CuCl2 solution, resulting in a Cu-loaded solution. 2+ Coffee grounds recycled membrane.
[0049] Example 3 The difference between this embodiment and Embodiment 1 is that the 0.5 mol / L AlCl3 solution in step (4) is replaced with a 0.5 mol / L ZnCl2 solution, resulting in a Zn-loaded solution. 2+ Coffee grounds recycled membrane.
[0050] Example 4 The difference between this embodiment and embodiment 1 is that the concentration of the AlCl3 solution in step (4) is 0.05 mol / L.
[0051] Example 5 The difference between this embodiment and embodiment 1 is that the concentration of the AlCl3 solution in step (4) is 0.2 mol / L.
[0052] Example 6 The difference between this embodiment and embodiment 1 is that the concentration of the AlCl3 solution in step (4) is 1 mol / L.
[0053] Comparative Example The difference between this embodiment and embodiment 1 is that the 0.5 mol / L AlCl3 solution in step (4) is replaced with distilled water to obtain a coffee grounds regenerated membrane.
[0054] Test Example 1: Antibacterial Test The antibacterial activity of the coffee grounds regenerated membranes obtained in Examples 1-3 and the comparative example against Staphylococcus aureus (S. aureus, Gram-positive) was tested. Prepared LB agar liquid culture medium was treated in an autoclave at 121°C for 20 min. After sterilization, it was placed in a laminar flow hood for UV sterilization for 30 min, and the agar was allowed to cool and solidify. An appropriate amount of Staphylococcus aureus suspension was added to sterilized distilled water and mixed to obtain 1.5 × 10⁻⁶ ppm. 8 CFU mL −1 The bacterial concentration was determined. Then, 0.05 mL of Staphylococcus aureus suspension was added to an LB agar plate. A circular film sample with a diameter of 7.5 mm was placed on the surface of the LB agar plate and incubated at 37 °C for 12 h. The size of the inhibition zone of the coffee grounds film on the plate was then observed.
[0055] The antibacterial effects of Examples 1, 2, 3 and the comparative examples were tested using the inhibition zone method. Figure 2 As shown, the membranes in Examples 1, 2, and 3 all have obvious antibacterial zones on their outer periphery, and the order of antibacterial ability is as follows: Example 3 (Zn 2+ Example 2 (Cu) 2+ Example 1 (Al) 3+The results demonstrate that all the examples exhibit good antibacterial properties. In contrast, the membrane in the comparative example was completely covered by bacterial colonies and did not show any antibacterial activity. This also verifies that the presence of metal ions in the membrane imparts good antibacterial properties to the coffee grounds membrane.
[0056] Test Example 2: Mechanical Performance Test Tensile testing was conducted using a tensile testing machine. According to GB / T1040.2-2006, the coffee grounds recycled films obtained in Examples 1, 2, 3, and the comparative example were cut into rectangular strips of 200 mm × 10 mm, and the average thickness of the samples was measured. The strips were then equilibrated under standard conditions for 48 hours. The tensile properties of the samples were tested using a tensile testing machine. Five coffee grounds recycled films of each type were taken, and transverse and longitudinal samples were cut for testing. The tensile speed was set to 5 mm·min. -1 The gauge length was 40 mm. The average maximum load and fracture displacement in the transverse and longitudinal directions of each coffee grounds recycled membrane were recorded, and the mechanical property data of each type of coffee grounds recycled membrane were calculated.
[0057] The formulas for calculating tensile strength, elongation at break, and modulus of elasticity are shown below: σt=p / (b·d); ε = x / L0 × 100%; E = σt / ε; Where: σt——tensile strength (MPa); p——maximum load (N); b——sample width (mm); d——thickness (mm); ε——elongation at break (%); x——fracture displacement (mm); L0——gauge length (mm); E——elastic modulus (GPa).
[0058] Table 1 As shown in Table 1, compared with the comparative examples, Examples 1, 2, and 3 all exhibited higher tensile strength, indicating that the coordination bonding between metal ions and the coffee grounds membrane significantly enhanced the physical properties of the coffee grounds membrane. Furthermore, the recycled coffee grounds membranes obtained in Examples 1-3 all possessed good elastic modulus and tensile strength, demonstrating excellent load-bearing capacity when used as packaging films.
[0059] Test Example 3: Preservation Effect Test Mangoes were used as the research object and classified according to the consistency of size, appearance, and ripeness. They were then sealed and stored separately in commercially available PE packaging bags and the coffee grounds recycled film obtained in Example 3. At room temperature, changes in the mangoes' decay rate, surface bacterial count, and other indicators were observed and tested at different storage times, with three parallel experiments conducted.
[0060] (1) Rot rate test Each package contained a fixed set of mangoes, and their rot rate was measured using the following formula: Rot rate (%) = Rotten fruit / Total number of fruits surveyed × 100%.
[0061] (2) Total bacterial count test on mango peel Mangoes in commercial PE packaging and those packaged in Example 3, stored for different periods, were selected. 4 g of the mango peel was taken and placed in a sterile centrifuge tube. 36 mL of sterile physiological saline was added, and the tube was shaken continuously for 35 min at 25 ℃ and 60 rpm / min using a constant-temperature shaker to obtain a microbial culture of the mango peel. The obtained culture was then diluted sequentially with sterile physiological saline at a ratio of 1:9 to achieve appropriate concentration gradients.
[0062] Culturing was performed using plate counting agar: Plate counting agar was prepared and autoclaved at 121 °C for 20 min. 100 μL of mango bacterial suspension at different dilution gradients was spread onto plates using the plate plating method, with two replicates for each concentration gradient. After plating, the plates were incubated at 37 °C for 24 h. The number of colonies was recorded after incubation, and the data were processed and expressed as log (CFU / g).
[0063] The growth of bacteria and fungi on the surface of fruit accelerates its decay and shortens its storage time. Figure 4 The data on the number of bacterial colonies on the surface of mangoes clearly show that the number of bacterial colonies on the surface of mangoes packaged with the coffee grounds recycled film obtained in Example 3 is generally lower than that of mangoes packaged in commercially available PE packaging, indicating that its antibacterial properties can significantly inhibit the growth of fungi and bacteria on the surface of mangoes. Furthermore... Figure 3 The data on mango decay rate shown also indicate that the decay rate of mangoes packaged with the coffee grounds recycled film obtained in Example 3 is significantly lower than that of commercially available PE, which can slow down the decay rate and extend the storage period of mangoes.
[0064] It is understood that the above embodiments only illustrate preferred embodiments of the present invention, and their descriptions are relatively specific and detailed, but they should not be construed as limiting the scope of the present invention. It should be noted that those skilled in the art can freely combine the above technical features without departing from the concept of the present invention, and can also make several modifications and improvements, all of which fall within the protection scope of the present invention. Therefore, all equivalent transformations and modifications made with respect to the scope of the claims of the present invention should fall within the scope of the claims of the present invention.
Claims
1. A method for preparing a coffee grounds recycled membrane, characterized in that, Includes the following steps: (1) The coffee grounds are degreased and dried to obtain degreased coffee grounds; (2) Dissolve the defatted coffee grounds to obtain a coffee grounds solution; (3) The coffee grounds solution is poured into a mold and cooled to obtain coffee grounds sol; (4) The coffee grounds sol was placed in a metal ion solution and coagulated and regenerated to obtain coffee grounds regenerated gel; (5) The coffee grounds regenerated gel is hot-pressed and dried to obtain a coffee grounds regenerated membrane.
2. The method for preparing the coffee grounds regenerated membrane according to claim 1, characterized in that: The solvent used for dissolution in step (2) includes at least one of ionic liquid, alkaline urine solvent, and N-methylmorpholine-N-oxide aqueous solution.
3. The method for preparing the coffee grounds regenerated membrane according to claim 2, characterized in that: The ionic liquid includes at least one of 1-butyl-3-methylimidazolium chloride, 1-allyl-3-methylimidazolium chloride, and 1-ethyl-3-methylimidazolium acetate.
4. The method for preparing the coffee grounds recycled membrane according to claim 1, characterized in that: In step (2), the mass ratio of defatted coffee grounds to solvent in the dissolution process is 1:10-30; The dissolution temperature in step (2) is 90-140 ℃; the time is 3-36 h.
5. The method for preparing the coffee grounds recycled membrane according to claim 1, characterized in that: The concentration of metal ions in the metal ion solution in step (4) is 0.05-2 mol / L.
6. The method for preparing the coffee grounds recycled membrane according to claim 1, characterized in that: The metal ion solution in step (4) is a chloride salt solution of metal ions; The metal ions in the metal ion solution in step (4) include Cu. 2+ Zn 2+ Ca 2+ Mg 2+ Al 3+ At least one of them.
7. The method for preparing the coffee grounds recycled membrane according to claim 1, characterized in that: The solidification and regeneration in step (4) is carried out at a temperature of 15-25 °C for 6-24 h.
8. The method for preparing the coffee grounds regenerated membrane according to claim 1, characterized in that: The pressure of hot pressing drying in step (5) is 0.5-1.5 MPa; the temperature is 45-100 ℃; and the time is 3-36 h.
9. The coffee grounds regenerated membrane prepared by the preparation method according to any one of claims 1-8.
10. The application of the coffee grounds recycled film of claim 9 in the fields of packaging and preservation.