Method for making a material, and material obtained by the method

Abstract

Method for making a material from seaweed comprising the following steps, preferably in this order: - a phase of making available a raw material, said a raw material including seaweed, - a cleaning step of said raw material aimed at removing impurities or debris from the raw material, - a drying phase of this raw material, - a phase of shredding of said raw material, - a phase of surface functionalization of this raw material, aimed at improving its compatibility with other materials and characterized by the fact that the surface functionalization phase includes a sub-phase of surface activation that involves exposing the raw material to a flow of either steam or aeriform containing oxygen.

Description

[0001] METHOD FOR MAKING A MATERIAL, AND MATERIAL OBTAINED BY THE METHOD

[0002] The present invention concerns a method for the production of a material, in particular a method for the treatment of seaweed, in order to obtain a water-repellent and / or flame-retardant material, in addition to a water-repellent and / or flameretardant material obtained by this method.

[0003] The purpose of the invention is to propose a material that allows to overcome the drawbacks of the well-known solutions.

[0004] The possibility of using seaweed and derivatives for the production of functional materials is well known. In particular, thanks to their high content of minerals such as potassium, calcium, sodium and magnesium, seaweed is an excellent precursor for water-repellent materials. Studies have also been carried out on the possibility of using them also as precursors for flame-retardant materials.

[0005] In addition, the well-known methods require the use of special types of algae in order to make functional materials.

[0006] This is a drawback because it does not allow the use of locally sourced algae, or it can only be used in certain locations around the world.

[0007] However, these well-known materials are not fully satisfactory as the methods necessary for their realization are often complex and expensive, thus making the materials thus obtained not commercially exploitable.

[0008] The state of the art also includes document CN 10529717.

[0009] Another purpose of the invention is to propose a method that allows any type of algae to be used as a raw material.

[0010] Another purpose of the invention is to propose a method that can be implemented in different parts of the world, with different climates, and different environmental conditions.

[0011] Another purpose of the invention is to propose a method that allows the use of low-cost raw materials.

[0012] Another purpose of the invention is to propose a method that is simple and cheap to implement.

[0013] Another purpose of the invention is to propose a method that has a reduced ecological impact.Another purpose of the invention is to propose a method that allows the reuse of waste from other industries.

[0014] Another purpose of the invention is to propose a method that allows biodiversity to be encouraged.

[0015] Another purpose of the invention is to propose a method that allows to obtain a bio-stimulating material.

[0016] Another purpose of the invention is to propose a method that allows to obtain a material that has uniform properties.

[0017] Another purpose of the invention is to propose a method that allows to obtain a material that can be used as a coating.

[0018] Another purpose of the invention is to propose a method that allows to obtain a material that can be used in indoor or outdoor applications.

[0019] Another purpose of the invention is to propose a method that allows to obtain a material that is stable over time and has a high durability.

[0020] Another purpose of the invention is to propose a method that allows to obtain a material with bio-stimulating properties

[0021] Another purpose of the invention is to propose a method that is alternative and / or an improvement on the known solutions.

[0022] Another purpose of the invention is to propose a material

[0023] All these purposes, and others that will be clearly apparent from the description, are achieved by a method having the characteristics described in claim 1.

[0024] Other structural and functional characteristics of the present invention and the relative advantages over the known technique will be even clearer and more evident from an examination of the following description, referring to an exemplary and preferred, but not limiting, embodiment of the material object of the present invention.

[0025] The present invention concerns a method for the production of a material, and in particular concerns a method for the treatment of seaweed in order to produce a material, for example a flame retardant and / or water-repellent material.

[0026] According to the invention, the method involves a phase of making available a raw material, which preferably can include seaweed. Advantageously said raw material can include any type of seaweed, and therefore the method may not be limited to one type of seaweed, for example because of their mineral content, or their specific size or moisture. Advantageously, this allows the method to be applied according tothe invention to seaweed harvested locally anywhere in the world, further reducing the ecological impact of the method itself. Preferably, this raw material is a species with a high mineral content, preferably between 20 and 60% of the dry weight, and preferably between 20 and 40% of the dry weight.

[0027] In a form of implementation said phase of making available of at least one seaweed it may include a sub-phase of recovery of at least one seaweed from the waste of an industry, for example from the waste of the cosmetics industry or the food industry. In particular, these industries, which use seaweed for their processes, are known to discard algae or portions of algae that comprise more carbon and / or other minerals.

[0028] Advantageously, this raw material can be collected in a location that does not present contamination.

[0029] The method according to the invention may include a cleaning step of the raw material aimed at separating and / or removing impurities or other unwanted materials from the raw material to be used. For example, this cleaning phase can allow to remove residues of sand, sea salt, or other potential contaminants present on the surface of the raw material.

[0030] Appropriately, this cleaning phase may include washing the raw material in water. Appropriately, only one wash can be carried out or, if necessary, several washes can be carried out, for example by immersing the raw material in a container containing clean water, then removing the raw material, changing the water, and repeating the sequence until the water remains transparent.

[0031] In an embodiment, the method according to the invention can provide for a phase of extraction of liquids from the raw material aimed at extracting the liquids contained in the marine algae used, such as sap, or in any case their liquid fraction. Appropriately, this phase can be configured to lead to the removal of the entire liquid fraction of the raw material, including the cytosol. In particular, this phase can be subsequent to the shredding phase, in order to speed up the extraction process. Advantageously, this liquid extraction phase can be carried out by squeezing the raw material, in order to extract the liquid fraction, which is subsequently stored and reused, for example for the creation of a bio-stimulant product. In particular, the liquid extraction phase may also include the extraction of a component of minerals or other components dissolved and / or suspended in the liquid that is extracted. In addition, the method according to the invention may include a purification phaseof the raw material. Preferably the purification phase can follow said cleaning phase, alternatively they can be carried out simultaneously, as will be clear below.

[0032] Advantageously, the purification phase can be configured to prevent and / or slow down the decomposition of the raw material, for example by removing surface deposits including sugar, and / or removing and / or killing microorganisms responsible for decomposition such as bacteria or other living creatures, or killing components of the raw material that are still alive.

[0033] Advantageously, the purification phase can involve immersing the raw material in a suitable purifying solution, for example a solution, preferably aqueous including an acid, for example acetic acid or a base, preferably a weak base or hydrogen peroxide. Preferably, the pH of the solution used can be between 4 and 10. Advantageously, the purification phase can last between about 24 and about 48 hours.

[0034] It is clear that the cleaning phase can be substantially included in the purification phase, since the purification solution can also be effective for the removal of salt, or other debris.

[0035] Advantageously, the method according to the invention can include a drying phase configured to allow the drying of the raw material. Appropriately, this phase may be necessary even if the raw material has not previously been subjected to this cleaning and / or purification phase, since, coming from the sea, it may have a high degree of internal humidity.

[0036] Advantageously, this phase can be carried out at room temperature and pressure, for example in suitable dryers. Alternatively, this phase can be carried out in a dryer, at a high temperature and, preferably, with the aid of forced ventilation.

[0037] In addition, the method according to the invention may include a raw material shredding step, configured to reduce the size and / or grain size of the raw material. In particular, the shredding phase may involve placing the raw material, preferably dried, inside a millstone, in order to reduce its size. Advantageously, in this way, it is possible to increase the surface area of the raw material, improving its reactivity. Appropriately, this shredding phase can include a preliminary sub-phase of shredding aimed at obtaining a raw material with a particle size of a few cm, preferably less than about 2 cm, and a subsequent proper shredding phase.

[0038] Appropriately, this shredding phase can lead the raw material to have a particle size between 1 micrometer and 1 mm, and preferably between 100 and 500micrometers.

[0039] In addition, the method according to the invention may include a low-temperature heat treatment step aimed at carbonizing the raw material. Preferably said heat treatment step can be carried out after said shredding sub-step. Advantageously, this heat treatment phase can be carried out at a temperature between 600 -1000°C. In an alternative form of construction, the heat treatment step can be carried out at a temperature of between 250 and 500°C. This, in combination with other specific process parameters such as the nature of the starting raw material, its particle size, and the conditions of the functionalization sub-phase, better explained below, allow to reduce the heat treatment temperature, and consequently the production costs, while maintaining, at the same time, the characteristics of the final product.

[0040] Preferably, this heat treatment phase can be carried out in the absence of oxygen, in order to minimize the formation of carbon oxides, or in any case in order to favor the carbonization process.

[0041] In addition, the method according to the invention involves a surface functionalization phase configured to improve the reactivity of the raw material, and in particular of the grains that make up the raw material subjected to the shredding phase. Advantageously in this way the material can acquire better compactness and strength.

[0042] In particular, this surface functionalization phase may include a first sub-phase of surface activation, which may preferably involve immersing the raw material in a basic solution, for example containing sodium or potassium hydroxide, or phosphoric acid or zinc chloride. Alternatively, the sub-phase can be achieved by introducing steam, and preferably water vapour, at high temperature and / or pressure. In particular, the steam temperature can be maintained between 700 and 1000°C, and preferably between 800 and 950°C, at a pressure close to ambient pressure, and preferably at a slightly positive pressure, and more preferably at a pressure between 0.95 and 1.20 bar.

[0043] Appropriately, the steam can be superheated, so as to avoid condensation in the reactor pipes, generally at least 150-250°C at injection.

[0044] Advantageously, the vapor can be mixed with N2 in order to moderate the reactivity. Advantageously, the mixture can be dosed in order to obtain about 30-70% carbonization.This avoids the use of chemicals, simplifying wastewater disposal, and reducing the overall cost of the process, as well as leaving the final material purer and uncontaminated by the reagents used during the process. In another embodiment, the surface activation sub-phase can be accomplished by exposing the feedstock to an oxygen-containing gas, e.g. air, at a high temperature, preferably to a high-temperature air stream.

[0045] Advantageously, in a construction form, the air can be at a temperature between 250 and 500°C, so as to allow a greater formation of surface groups containing oxygen, and a moderate porosity of the material.

[0046] Advantageously, in another form of construction, the air can be at a temperature of 500-800°C, in order to increase the porosity of the resulting material.

[0047] Advantageously, the pressure can be between 0.95 and 1.2 bar, and preferably slightly higher than the ambient pressure.

[0048] This further simplifies the process, while also avoiding the need for an external steam generator. In particular, in this case the oxidation can be lighter than in the case of steam, and modify the surface chemistry more than the amount of pores present in depth.

[0049] In a further form of implementation, a gas flow containing between 1 and 10% O2 by volume can be realized, diluted in an inert gas such as N2, CO2 or another flow gas, in order to reduce the combustion effects and improve control over the reaction. Appropriately, in this way it is possible to achieve an increase in the porosity of the raw material, and consequently a further increase in the surface area of the raw material, in particular thanks to the formation of a sponge structure. Appropriately, the surface functionalization phase can also include a surface coating sub-phase, preferably subsequent to this surface activation sub-phase. Appropriately said surface coating sub-phase can be configured to allow the surface of the raw material to be covered, preferably in powder form, with a surface layer aimed at improving its compatibility with other materials.

[0050] Advantageously, for example, said surface coating sub-phase can involve coating the raw material with a layer of silicon-based material. For example, this can be achieved by immersing said raw material, which has preferably been subjected to this surface activation sub-step, in a solution containing silanes.

[0051] Preferably, following this surface functionalization phase, the solutions used can be appropriately neutralized before being discarded. Alternatively, they can be recycledin order to further reduce the environmental impact of the method. Preferably, for this purpose, the solutions, after use, can be stored inside watertight containers. In an embodiment aimed at the realization of a fireproof and waterproof material, it can provide for this phase of heat treatment at low temperature subsequently, and preferably just after said preliminary sub-phase of shredding.

[0052] In the embodiment aimed at the realization of a fireproof and waterproof material, the method according to the invention may provide for this shredding phase properly so said after, and preferably just after, said phase of heat treatment at low temperature.

[0053] In an embodiment aimed at the realization of a carbon-based activated material, the method according to the invention may provide for this phase of surface functionalization after, and preferably just after, said preliminary sub-phase of shredding.

[0054] In the embodiment aimed at the realization of a carbon-based activated material, the method according to the invention may provide for this phase of heat treatment at low temperature after, and preferably just after, said phase of surface functionalization.

[0055] In the embodiment aimed at the realization of an activated carbon-based material, the method according to the invention may provide for this shredding phase properly so said after, and preferably just after, said low-temperature heat treatment phase. From what has been said, it is clear that the method according to the invention is particularly advantageous, indeed, optimal, as it allows any type of seaweed to be used as a starting material, simplifying and making the supply chain more environmentally friendly, as well as allowing materials with competitive properties to be obtained.

Claims

CLAIMS1. Method for making a material from seaweed comprising the following steps, preferably in this order:a phase of making available a raw material, said a raw material including seaweed,a cleaning step of said raw material aimed at removing impurities or debris from the raw material,a drying phase of this raw material,a phase of shredding of said raw material,a phase of surface functionalization of this raw material, aimed at improving its compatibility with other materialsand characterized by the fact that the surface functionalization phase includes a sub-phase of surface activation that involves exposing the raw material to a flow of either steam or aeriform containing oxygen.

2. Method according to claim 1 characterised by the fact that this shredding phase involves a preliminary shredding sub-phase aimed at reducing the grain size of the raw material to a value of less than 10 centimetres, and more preferably less than 2 centimetres, and a shredding phase proper to reduce the size of the grain size between 1 micrometre and 1 millimetre, and preferably between 100 and 500 micrometers.

3. A method according to one or more of the above claims is characterised by the fact that it includes a heat treatment step of that raw material, and that this low-temperature heat treatment step takes place after, and preferably immediately after, that preliminary shredding sub-stage.

4. A method according to one or more of the above claims characterised by the fact that it includes a step in the extraction of liquids from that raw material.

5. A method according to one or more of the above claims characterized by the fact that this heat treatment step is carried out in the absence of oxygen.

6. A method according to one or more of the above claims characterized by the fact that this surface functionalization phase involves a surface activation subphase, which involves immersing this raw material in a solution including sodium hydroxide.

7. A method according to one or more of the above claims characterised by thefact that this surface functionalisation step involves a surface coating sub-step, aimed at covering the raw material with a layer aimed at improving its compatibility with other materials, for example by immersion in a solution containing silanes.

8. A method according to one or more of the above claims characterized by the fact that it includes a purification step aimed at removing bacteria and / or microorganisms from the raw material.

9. A method according to one or more of the above claims characterized by the fact that this purification step involves placing the raw material in a solution including a solvent, e.g. acetic acid and / or hydrogen peroxide.

10. A method according to one or more of the above claims characterized by the fact that this raw material can include seaweed of any species.

11. A method according to one or more of the above claims characterized by the fact that the temperature of the steam can be maintained between 700 and 1000°C, and preferably between 800 and 950°C.

12. A method according to one or more of the above claims characterized by the fact that the steam pressure is between 0.95 and 1.2 bar, and preferably between 1 and 1.2 bar.

13. Method according to one or more of the above claims characterized by the fact that the steam is superheated preferably by at least 150-250°C at injection.

14. A method according to one or more of the above claims characterized by the fact that the flow during the surface functionalization phase is a flow of air at a temperature between 250 and 500°C.

15. A method according to one or more of the above claims characterized by the fact that the flow during the surface functionalization phase is an air flow at a temperature between 500 and 800°C16. A method according to one or more of the above claims characterized by the fact that the flow during the surface functionalization phase is an air flow at a pressure between 0.95 and 1.2 bar, and preferably between 1 and 1.2 bar17. A method according to one or more of the above claims characterized by the fact that the flow during the surface functionalization phase is a flow of gas containing between 1 and 10% of O2 by volume, diluted in an inert gas.