Seawater condensation-type composite catalyst composition

Abstract

The present disclosure relates to a seawater-sensitive composite catalyst composition, and more specifically, to a composite catalyst composition that generates radicals capable of decomposing polymers in seawater and visible light environments.

Description

Technology Field

[0001] The present disclosure relates to a seawater-sensitive composite catalyst composition, and more specifically, to a composite catalyst composition that generates radicals capable of decomposing polymers in seawater and visible light environments. Background Technology

[0002] Generally, plastic waste generated on land eventually flows into the ocean. This marine plastic waste breaks down into microplastics several micrometers in size due to weathering and corrosion, causing harm to marine life over a wide range of areas and even biologically affecting humans. Furthermore, undegraded plastic accumulates due to ocean currents, leading to ecological problems such as the formation of a plastic waste island in the North Pacific 17 times the size of the Korean Peninsula.

[0003] To address these plastic problems, biodegradable polymers that decompose under specific conditions are being proposed. Biodegradable polymers are characterized by natural decomposition mainly by enzymes produced by specific microorganisms (Green Chem. 2020, 22, 7778), but since it is difficult to arbitrarily control the culture conditions of microorganisms in a natural environment, there are limitations in controlling actual biodegradable polymers to decompose naturally.

[0004] In addition, as a UV-ozone-based biodegradation technology, a method of degrading polymers with enzymes using azobenzene as a motif, which is degraded by ultraviolet light, has been proposed (RSC Advances 2017, 7, 55720), but this also has the limitation that the ultraviolet environment must be artificially created.

[0005] In addition, as a degradation-based biodegradation technology, a method has been proposed to degrade polymers by inducing transesterification and cis-elimination through heat treatment at temperatures above 200 degrees Celsius. However, this method has the limitation that an additional degradation process is required after collection for biodegradation, which makes it difficult to apply to plastic waste released into nature.

[0006] In order to overcome the various problems of such conventional technology, there is an urgent need to provide a means of decomposing polymers by controlling on / off via a spontaneous trigger in a natural environment without a separate processing step. The problem to be solved

[0007] The problem that the present disclosure aims to solve is to provide a seawater-sensitive composite catalyst composition that does not decompose polymers or decomposes them slowly under normal usage environments, but increases polymer decomposition power when exposed to seawater and visible light environments.

[0008] Another problem that the present disclosure aims to solve is to provide a seawater-sensitive composite catalyst composition that does not decompose a polymer when a seawater or visible light environment is not provided, and can decompose a polymer only when a seawater and visible light environment is provided.

[0009] Another problem that the present disclosure aims to solve is to provide a seawater-sensitive composite catalyst composition having an iron nanoparticle core surface-coated with a porous coating material, thereby preventing natural oxidation of the iron nanoparticle core in a normal usage environment, having a wide band gap so as not to have visible light activity, and being able to decompose a polymer only when a seawater and visible light environment is provided.

[0010] Another problem that the present disclosure aims to solve is to provide a seawater-sensitive composite catalyst composition that can be included in various polymer products such as plastic bags, packaging materials, containers, and clothing fibers, and in particular, can offer significant advantages from an environmental and efficiency perspective for disposable materials such as masks, which are used in large quantities as single-use items and are subsequently discarded, thereby having an adverse effect on the environment.

[0011] The problems that the present disclosure aims to solve are not limited to those mentioned above, and any unmentioned problems that the present disclosure aims to solve will be clearly understood by a person skilled in the art to which the present disclosure belongs ("person skilled in the art") from the description below. means of solving the problem

[0012] According to one embodiment of the present disclosure, a seawater-sensitive composite catalyst composition may be provided, characterized by generating hydroxyl radicals when irradiated with light having a wavelength in the range of 200 to 800 nm after being immersed in an aqueous NaCl solution.

[0013] For example, the seawater-sensitive composite catalyst composition may be characterized by being immersed in an aqueous NaCl solution at a concentration of 0.001 to 0.010 g / L.

[0014] For example, the above NaCl aqueous solution may be characterized as being an aqueous solution with a concentration of 25 to 45 per mille.

[0015] For example, the above seawater-sensitive composite catalyst composition may be characterized by being immersed in an aqueous NaCl solution for at least one hour.

[0016] For example, the seawater-sensitive composite catalyst composition may be characterized by an increase in absorbance of 10 to 200% for light having a wavelength in the range of 200 to 800 nm after being immersed in an aqueous NaCl solution.

[0017] For example, the seawater-sensitive composite catalyst composition may be characterized by forming a band gap of 1.5 to 2.5 eV after being immersed in an aqueous NaCl solution.

[0018] For example, the seawater-sensitive composite catalyst composition may be characterized in that the concentration of the generated hydroxyl radical is 1 nM to 1 mM.

[0019] For example, the seawater-sensitive composite catalyst composition may be characterized by having a zero-valent iron nanoparticle core surface-coated with a porous coating material.

[0020] For example, the above zero-valent iron nanoparticle core may be characterized by having an average diameter of 20 to 150 nm.

[0021] For example, the porous coating material may be characterized by having a band gap of 1 to 9 eV.

[0022] For example, the porous coating material may be one or more selected from the group comprising aluminum oxide, silica, titanium oxide, and zinc oxide.

[0023] For example, the porous coating material may be characterized by being surface-coated with a thickness of 2 to 100 nm.

[0024] According to another embodiment of the present disclosure, a seawater-sensitive degradable polymer material comprising the seawater-sensitive composite catalyst composition may be provided.

[0025] For example, the polymer component included in the seawater-sensitive degradable polymer material may be one or more selected from the group comprising polyethylene, polypropylene, polystyrene, and polyvinyl chloride.

[0026] For example, the seawater-sensitive composite catalyst composition included in the above seawater-sensitive degradable polymer material may be included in an amount of 0.001 to 10 parts by weight based on 100 parts by weight of the total polymer material. Effects of the invention

[0027] According to the present disclosure, a seawater-sensitive composite catalyst composition may be provided in which the polymer is not degraded or is degraded slowly under normal usage conditions, but the polymer degradation ability increases only when a seawater and visible light environment is provided.

[0028] In addition, according to the present disclosure, a seawater-sensitive composite catalyst composition may be provided that does not decompose a polymer when a seawater or visible light environment is not provided, and decomposes a polymer only when a seawater and visible light environment is provided.

[0029] In addition, according to the present disclosure, a seawater-sensitive composite catalyst composition having an iron nanoparticle core surface-coated with a porous coating material is provided, thereby preventing natural oxidation of the iron nanoparticle core in a normal usage environment, having a wide band gap so as not to have visible light activity, and being able to decompose a polymer only when a seawater and visible light environment is provided.

[0030] In addition, according to the present disclosure, a seawater-sensitive composite catalyst composition can be provided that can be included in various polymer products such as plastic bags, packaging materials, containers, and clothing fibers, and can provide significant advantages in terms of environmental and efficiency for disposable materials, such as masks, which are used in large quantities for single use and are subsequently discarded, thereby having an adverse effect on the environment.

[0031] The superior and / or useful effects according to the present disclosure are not limited to the effects of the present disclosure described above, and a person skilled in the art will also be able to obviously recognize, based on the disclosure of the present specification, superior and / or useful effects of the present disclosure that are not explicitly disclosed in the present specification, and it should be understood that these are intentionally disclosed by the present specification and are obviously included within the scope of the present disclosure. Brief explanation of the drawing

[0032] FIG. 1 is a diagram briefly illustrating the concept of a seawater-sensitive composite catalyst composition according to one embodiment of the present disclosure. FIG. 2 is a figure showing XRD data of a seawater-sensitive composite catalyst composition according to one embodiment of the present disclosure. FIG. 3 is a figure showing XRD data after exposure to a seawater simulated environment of a seawater-sensitive composite catalyst composition according to one embodiment of the present disclosure. FIG. 4 is a figure showing data on the change in absorbance before and after oxidation of a seawater-sensitive composite catalyst composition according to one embodiment of the present disclosure. FIG. 5 is a figure showing the bandgap formation evaluation result data of a seawater-sensitive composite catalyst composition according to one embodiment of the present disclosure. FIG. 6 is a figure showing visible light activity data of a seawater-sensitive composite catalyst composition according to one embodiment of the present disclosure before exposure to a seawater simulated environment. FIG. 7 is a figure showing visible light activity data after exposure to a seawater simulated environment of a seawater-sensitive composite catalyst composition according to one embodiment of the present disclosure. FIG. 8 is a figure showing result data evaluating the amount of radicals generated by a seawater-sensitive composite catalyst composition according to one embodiment of the present disclosure. FIG. 9 is a figure showing result data evaluating the amount of radicals generated by a seawater-sensitive composite catalyst composition according to one embodiment of the present disclosure. FIG. 10 is a figure showing result data evaluating the amount of radicals generated by a seawater-sensitive composite catalyst composition according to one embodiment of the present disclosure. Specific details for implementing the invention

[0033] The terms or words used in this specification and claims are not intended to be interpreted as being limited to their commonly accepted dictionary meanings, and a person skilled in the art will clearly understand that said terms or words are used within the scope of conveying what this disclosure means, within the scope of expressing the concept that this specification and claims obviously intend to convey.

[0034] Furthermore, a person skilled in the art will clearly understand that the configurations described in the aspects, modes of embodiment, examples, etc., of the present disclosure described in this specification are merely preferred examples presented at the time to enable a person skilled in the art to understand and reproduce the present disclosure, and are not intended to limit the present disclosure thereto.

[0035] Furthermore, the descriptions and specific embodiments regarding each configuration described in this specification may be obviously applied to the descriptions and specific embodiments of each other configuration. That is, a person skilled in the art will clearly understand that all possible combinations of the various configurations and specific embodiments disclosed in this specification fall within the scope disclosed herein.

[0036] As used herein, the term "and / or" is a term comprising each of the items mentioned and all combinations of two or more. Additionally, where a singular term is used herein, it is disclosed including the plural form unless otherwise noted.

[0037] As used herein, the terms "comprise" and "comprising" are terms that permit the existence or addition of items other than those mentioned, and as used herein, the terms "consist," "consist," "consisting," and "consisting" are terms that do not permit the existence or addition of items other than those mentioned.

[0038] As used in this specification, the term "to" indicates a numerical range in which the range of values ​​represented by "to" includes the values ​​listed before and after the term as lower and upper values, respectively. Where multiple upper and / or lower values ​​of an arbitrary numerical range are disclosed, the numerical range is disclosed such that any one of the multiple lower values ​​and any one of the multiple upper values ​​are respectively set as the lower and upper values.

[0039] The terms “about” and / or “approximately” as used in this specification refer to a numerical range between a 10% upper limit value and a lower limit value based on the value indicated using “about” and / or “approximately”.

[0040] Terms or words used in this specification and claims should not be interpreted as being limited to their ordinary dictionary meanings, but should be interpreted in a meaning and concept consistent with the technical spirit of this disclosure, based on the principle that the inventor can appropriately define the concept of the terms to best describe his invention. Accordingly, the configurations described in the embodiments of this specification are merely preferred embodiments of this disclosure and do not represent all of the technical spirit of this disclosure; therefore, it should be understood that various equivalents and modifications that can replace them may exist at the time of filing this application.

[0041] Meanwhile, each description and embodiment disclosed in this specification may also be applied to other descriptions and embodiments. That is, all combinations of the various elements disclosed in this specification fall within the scope of this disclosure, and descriptions omitted in one embodiment may be interpreted in the same manner as described in other embodiments. Furthermore, the scope of this disclosure should not be considered limited by the specific descriptions provided below.

[0042] According to one embodiment of the present disclosure, a seawater-sensitive composite catalyst composition may be provided, characterized by generating hydroxyl radicals when irradiated with light having a wavelength in the range of 200 to 800 nm after being immersed in an aqueous NaCl solution.

[0043] For example, the seawater-sensitive composite catalyst composition may be characterized by being immersed in an aqueous NaCl solution at a concentration of 0.001 to 0.010 g / L. Preferably, the concentration of the seawater-sensitive composite catalyst composition may be 0.003 to 0.009 g / L, more preferably 0.005 to 0.008 g / L, even more preferably 0.006 to 0.008 g / L, and most preferably 0.0075 g / L.

[0044] For example, the above NaCl aqueous solution may be characterized as being an aqueous solution with a concentration of 25 to 45 per mille. Preferably, the above NaCl aqueous solution may be an aqueous solution with a concentration of 28 to 42 per mille, more preferably an aqueous solution with a concentration of 30 to 40 per mille, even more preferably an aqueous solution with a concentration of 32 to 38 per mille, and most preferably an aqueous solution with a concentration of 35 per mille.

[0045] For example, the seawater-sensitive composite catalyst composition may be characterized by being immersed in an aqueous NaCl solution for at least one hour. Preferably, the seawater-sensitive composite catalyst composition may be immersed in an aqueous NaCl solution for 2 to 200 hours, more preferably for 3 to 150 hours, even more preferably for 3.5 to 100 hours, and most preferably for 4 hours or more, up to 96 hours.

[0046] The above hydroxyl radicals can be used to decompose polymer materials when generated. This allows hydroxyl radicals to be generated from the composite catalyst composition when the polymer material containing the seawater-sensitive composite catalyst composition is exposed to a marine environment, that is, when exposed to both a seawater environment and a visible light environment. The polymer material is then decomposed by the generated hydroxyl radicals, thereby enabling waste plastics discarded into the ocean to decompose naturally without the need for separate artificial decomposition conditions. For example, the seawater-sensitive composite catalyst composition can be immersed in a 35 per mille aqueous solution of NaCl at a concentration of 0.0075 g / L for 24 hours, and then irradiated with light having a wavelength of 400 nm. The seawater-sensitive composite catalyst composition can absorb light having a wavelength of 400 nm and use that energy to separate water molecules into hydroxyl radicals, thereby enabling the generation of hydroxyl radicals. That is, the seawater-sensitive composite catalyst composition according to the present disclosure can promote the decomposition of various organic materials, such as polymeric materials or waste plastics, as the amount of hydroxyl radicals generated increases when exposed to a seawater environment and a visible light environment, and the catalytic activity increases.

[0047] For example, the seawater-sensitive composite catalyst composition may be characterized by an increase in absorbance of light having a wavelength in the range of 200 to 800 nm by 10 to 200% after being immersed in an aqueous NaCl solution. That is, when the seawater-sensitive composite catalyst composition is immersed in seawater, the catalytic activity changes, and as a result, the absorbance is also affected. For example, the seawater-sensitive composite catalyst composition may have an increase in absorbance of light having a wavelength of 400 nm by 40% after being immersed for 24 hours in an aqueous NaCl solution of 35 per mille at a concentration of 0.0075 g / L. This means that the seawater-sensitive composite catalyst composition absorbs only 10% of light having a wavelength of 400 nm before being immersed in seawater, and absorbs 50% after being immersed in seawater. In other words, the catalytic activity of the seawater-sensitive composite catalyst composition increases when immersed in seawater; this is because the light absorption increases, allowing more light to be absorbed and enabling light-activated catalytic reactions to occur more effectively.

[0048] For example, the seawater-sensitive composite catalyst composition may be characterized by forming a band gap of 1.5 to 2.5 eV after being immersed in an aqueous NaCl solution, and preferably by forming a band gap of about 2.1 eV. By forming such a characteristic band gap, the seawater-sensitive composite catalyst composition may cause the catalytic activity of the zero-valent iron nanoparticle core contained in the composition to change, thereby generating radicals.

[0049] For example, the seawater-sensitive composite catalyst composition may be characterized in that the concentration of the generated hydroxyl radical is 1 nM to 1 mM, and preferably 1.51 x 10⁻⁶ 4 It can be characterized as being nM (=15.1μM).

[0050] For example, the seawater-sensitive composite catalyst composition may be characterized by having a zero-valence iron nanoparticle core surface-coated with a porous coating material. The seawater-sensitive composite catalyst composition may have a nanoparticle core made of an iron element with a valence of zero, and the surface is covered with a porous coating material, so that it can be controlled to generate radicals only when both a seawater environment and a visible light environment are provided.

[0051] For example, the above zero-valent iron nanoparticle core may have an average diameter of 20 to 150 nm. That is, by having a fine iron nanoparticle core in the catalyst composition, when the iron nanoparticle core comes into contact with seawater and oxidizes, its physical properties change to generate radicals, and the generated radicals can be used to decompose polymers.

[0052] For example, the porous coating material may have a band gap of 1 to 9 eV. A band gap is a value representing the range of energy that electrons in a material can occupy; if the band gap is large, electrons absorb a large amount of energy, and if the band gap is small, electrons absorb less energy, and the band gap affects the optical, electrical, and thermal properties of the material. For example, the porous coating material may have a band gap of 2.0 eV. In this case, the porous coating material may absorb some of the visible light and reflect ultraviolet light, and in this case, the porous coating material may appear white or light in color. That is, the band gap of the porous coating material affects the optical properties of the composite catalyst composition, and the band gap of the porous coating material determines the range of light that the composite catalyst composition absorbs or reflects, which may also affect the activity of the composite catalyst.

[0053] For example, the porous coating material may be one or more selected from the group comprising aluminum oxide, silica, titanium oxide, and zinc oxide. Each of the above components has different band gaps and chemical properties. For example, if the porous coating material is composed of a mixture of aluminum oxide and titanium oxide, aluminum oxide may have a band gap of 8.8 eV and titanium oxide may have a band gap of 3.0 eV, and the band gap of the porous coating material can be controlled by mixing these two materials. That is, the constituent components of the porous coating material affect the chemical properties of the composite catalyst composition and, furthermore, may affect the acid-base, surface area, electrical conductivity, etc. of the composite catalyst composition.

[0054] For example, the porous coating material may be surface-coated with a thickness of 2 to 100 nm. For example, the porous coating material may be surface-coated with a thickness of 50 nm. If the thickness of the porous coating material is appropriate, pores are formed on the surface of the catalyst composition, which can increase catalytic activity; however, if the thickness is too large or too small, pores may become blocked or not formed, which can reduce catalytic activity.

[0055] That is, the seawater-sensitive composite catalyst composition according to the present disclosure can generate radicals by changing the catalytic activity of the zero-valent iron nanoparticle core, by allowing various ions and seawater contained in the seawater to pass through the surface coated with a porous coating material when exposed to a seawater environment.

[0056] According to another embodiment of the present disclosure, a seawater-sensitive degradable polymer material comprising the seawater-sensitive composite catalyst composition may be provided. The seawater-sensitive degradable polymer material comprising the seawater-sensitive composite catalyst composition may promote the degradation of a polymer product when the polymer product containing the material is disposed of in the ocean, as the seawater-sensitive composite catalyst composition contained in the material is exposed to a seawater environment and a visible light environment, and may cause the polymer product to naturally degrade without the creation of an artificial degradation environment.

[0057] For example, the polymer component included in the above seawater-sensitive degradable polymer material may be one or more selected from the group including polyethylene, polypropylene, polystyrene, and polyvinyl chloride. Although the above polymer component generally takes a long time to decompose after disposal, the decomposition may take a relatively short time due to radicals generated when the seawater-sensitive composite catalyst composition included in the seawater-sensitive degradable polymer material according to the present disclosure is exposed to a marine environment and a visible light environment. Such features of the present disclosure allow the polymer material containing both the conventional low-degradability polymer material and the seawater-sensitive composite catalyst composition according to the present disclosure to have excellent natural decomposition characteristics even when disposed of in the ocean, thereby having a positive impact on the environment and enhancing the environmental friendliness of the material. That is, the seawater-sensitive degradable polymer material is composed of a combination of a seawater-sensitive composite catalyst composition and a polymer component, and the polymer component can be selected from plastic materials with low degradability; however, due to the presence of the seawater-sensitive composite catalyst composition, the degradability of the material can be increased as seawater and visible light environments are created.

[0058] For example, the seawater-sensitive composite catalyst composition included in the seawater-sensitive degradable polymer material may be included in an amount of 0.001 to 10 parts by weight based on 100 parts by weight of the total polymer material. For example, the seawater-sensitive composite catalyst composition included in the seawater-sensitive degradable polymer material may be included in an amount of 5 parts by weight based on 100 parts by weight of the total polymer material. When the seawater-sensitive composite catalyst composition is included within the above numerical range based on 100 parts by weight of the total polymer material, the degradability of the polymer material can be improved while maintaining physical properties based on the polymer components included in the polymer material.

[0059] The present disclosure is described in more detail below using examples. Process conditions and preparation steps not specified in the following examples may be obvious in the art to which the present disclosure belongs, and a person skilled in the art will be able to select them without difficulty based on the present disclosure and reproduce the problem-solving principles of the present disclosure.

[0060] In addition, regarding the manufacturing method according to the present disclosure, unless otherwise specified, each step constituting the manufacturing method is to be understood as being carried out at room temperature (25°C) and each step is to be performed by means and tools that a person skilled in the art can derive without particular difficulty.

[0061] Example 1: Preparation of a seawater-sensitive composite catalyst composition according to the present disclosure

[0062] FIG. 1 is a diagram briefly illustrating the concept of a seawater-sensitive composite catalyst composition according to one embodiment of the present disclosure. Referring to FIG. 1, it can be seen that the seawater-sensitive composite catalyst composition according to the present disclosure has a structure comprising a core made of zero-valent iron nanoparticles and a coating layer formed on the surface of the core, the coating layer being formed of a porous coating material.

[0063] First, to synthesize zero-valent iron nanoparticles, an aqueous iron chloride solution and an aqueous sodium borohydride solution were mixed to perform a reduction reaction, and then the resulting zero-valent iron nanoparticles were filtered, collected, and dried.

[0064] Next, silica was selected as the porous coating material and mixed with a precursor and a solvent to create a solution. Then, the solution was evaporated to obtain a powder of the porous coating material.

[0065] Finally, the above zero-valent iron nanoparticle core and porous coating material were mixed and heat-treated for an appropriate temperature and time so that the porous coating material was coated on the surface of the zero-valent iron nanoparticle core, and the final seawater-sensitive composite catalyst composition was filtered and dried to prepare the composition of Example 1.

[0066] In the following experimental examples, the seawater environment was simulated with a 35 per mille NaCl solution, and the visible light environment was simulated with wavelengths of 350 to 1100 nm, 15,000 lumens, and a color temperature of 5,500 K.

[0067] Experimental Example 1: Measurement of XRD Data of Seawater-Sensitive Composite Catalyst Composition

[0068] FIG. 2 is a figure showing XRD data of a seawater-sensitive composite catalyst composition according to one embodiment of the present disclosure, and FIG. 3 is a figure showing XRD data of a seawater-sensitive composite catalyst composition according to one embodiment of the present disclosure after exposure to a seawater simulated environment. Referring to FIG. 2 and FIG. 3, a characteristic single peak (intensity 110) was observed near 2-theta 45 before exposure to a seawater environment, but multiple characteristic peaks were observed after exposure to a seawater environment for 24 hours, confirming that the structure was effectively changed upon exposure to a seawater environment.

[0069] Experimental Example 2: Evaluation of Absorbance Change of Seawater-Sensitive Composite Catalyst Composition

[0070] FIG. 4 is a figure showing data on the change in absorbance before and after oxidation of a seawater-sensitive composite catalyst composition according to one embodiment of the present disclosure. Referring to FIG. 4, when the absorbance of the seawater-sensitive composite catalyst composition was measured using a UV-vis spectrophotometer with a measurement wavelength range of 200 to 800 nm, a particle concentration of 0.0075 g / L, and isopropanol as the solvent, an increased absorbance of approximately 33.34% was observed based on light of a wavelength of approximately 500 nm after oxidation occurred due to exposure to a seawater environment for 24 hours, confirming that the absorbance for light in the visible light region increased when exposed to a seawater environment.

[0071] Experimental Example 3: Evaluation of Bandgap Formation of Seawater-Sensitive Composite Catalyst Composition

[0072] FIG. 5 is a figure showing the results of a bandgap formation evaluation of a seawater-sensitive composite catalyst composition according to one embodiment of the present disclosure. Referring to FIG. 5, it was confirmed that the seawater-sensitive composite catalyst composition formed a bandgap of approximately 2.1 eV when using a torque plot method based on the absorbance value and light energy measured when oxidation occurred due to exposure to a seawater environment for 24 hours.

[0073] Experimental Example 4: Measurement of Visible Light Activity of Seawater-Sensitive Composite Catalyst Composition Upon Seawater Exposure

[0074] FIG. 6 is a figure showing visible light activity data of a seawater-sensitive composite catalyst composition according to one embodiment of the present disclosure before exposure to a seawater simulated environment, and FIG. 7 is a figure showing visible light activity data of a seawater-sensitive composite catalyst composition according to one embodiment of the present disclosure after exposure to a seawater simulated environment. Measurements were performed under conditions of TPA concentration: 0.0005M, NaOH concentration: 0.010M, particle concentration: 0.04g / L, fluorescence analysis HT voltage: 200V, fluorescence analysis excitation wavelength: 315nm, and fluorescence analysis measurement wavelength range: 335-800nm. In the case of TPA, it reacts with hydroxyl radicals to produce hydroxyl terephthalic acid (h-TPA), and in the case of h-TPA, it emits light at 350-500nm, thereby confirming the generation of hydroxyl radicals.

[0075] Referring to FIG. 6 above, it was confirmed that the seawater-sensitive composite catalyst composition according to the present disclosure exhibits similar activity characteristics when exposed to a visible light environment before being exposed to a seawater environment, but referring to FIG. 7 above, increased h-TPA generation was observed in the wavelength range of about 350 to 500 nm when exposed to a visible light environment after being exposed to a seawater environment, thus confirming that it exhibits visible light activity only when exposed to a seawater environment and a visible light environment.

[0076] Experimental Example 5: Evaluation of Radical Generation Amount of Seawater-Sensitive Composite Catalyst Composition

[0077] FIGS. 8 to 10 are figures showing result data evaluating the amount of radicals generated by a seawater-sensitive composite catalyst composition according to one embodiment of the present disclosure. The measurement was performed with the methylene blue concentration set to 0.005 g / L, the particle concentration to 0.04 g / L, and the UV-vis measurement range set to 200 to 800 nm.

[0078] Referring to Figure 8 above, a correlation between the concentration of methylene blue and the measured intensity was confirmed, and the intensity is 7.33518 * 10 times the concentration of methylene blue 4 It was confirmed to have a value of a ship.

[0079] Referring to FIG. 9 above, it was confirmed that the seawater-sensitive composite catalyst composition according to the present disclosure generates hydroxyl radicals as oxidation occurs upon exposure to a seawater environment and a visible light environment, and that methylene blue is converted to leucomethylene blue by the hydroxyl radicals, resulting in a decrease in absorbance at 630 nm.

[0080] Referring to FIG. 10 above, as the concentration of methylene blue decreases from 0.00002 M to 0.0000049 M upon exposure to a seawater environment and a visible light environment for 7 hours, the seawater-sensitive composite catalyst composition according to the present disclosure is 1.5*10 4 It was confirmed that it generates nM (=15μM) of hydroxyl radicals.

[0081] Although preferred embodiments of the present disclosure have been described in detail above, the scope of the present disclosure is not limited thereto, and various modifications and improvements by those skilled in the art using the basic concepts of the present disclosure as defined in the following claims are also included within the scope of the present disclosure.

Claims

Claim 1 A seawater-sensitive composite catalyst composition comprising a zero-valent iron nanoparticle core surface-coated with a porous coating material, wherein the seawater-sensitive composite catalyst composition is characterized by generating hydroxyl radicals when irradiated with light having a wavelength in the range of 200 to 800 nm after being immersed in an aqueous NaCl solution. Claim 2 A seawater-sensitive composite catalyst composition according to claim 1, characterized in that the seawater-sensitive composite catalyst composition is immersed in an aqueous NaCl solution at a concentration of 0.001 to 0.010 g / L. Claim 3 A seawater-sensitive composite catalyst composition according to paragraph 2, wherein the NaCl aqueous solution is an aqueous solution with a concentration of 25 to 45 per mille. Claim 4 In paragraph 3, the seawater-sensitive composite catalyst composition is characterized by being immersed in an aqueous NaCl solution for at least one hour. Claim 5 A seawater-sensitive composite catalyst composition according to claim 4, characterized in that, after being immersed in an aqueous NaCl solution, the absorbance for light having a wavelength in the range of 200 to 800 nm increases by 10 to 200%. Claim 6 A seawater-sensitive composite catalyst composition according to claim 4, characterized in that the seawater-sensitive composite catalyst composition forms a band gap of 1.5 to 2.5 eV after being immersed in an aqueous NaCl solution. Claim 7 In claim 4, the seawater-sensitive composite catalyst composition is characterized in that the concentration of the generated hydroxyl radical is 1 nM to 1 mM. Claim 8 delete Claim 9 A seawater-sensitive composite catalyst composition according to claim 1, characterized in that the zero-valent iron nanoparticle core has an average diameter of 20 to 150 nm. Claim 10 A seawater-sensitive composite catalyst composition according to claim 1, characterized in that the porous coating material has a band gap of 1 to 9 eV. Claim 11 A seawater-sensitive composite catalyst composition according to claim 1, characterized in that the porous coating material is one or more selected from the group comprising aluminum oxide, silica, titanium oxide, and zinc oxide. Claim 12 A seawater-sensitive composite catalyst composition according to claim 1, characterized in that the porous coating material is surface-coated with a thickness of 2 to 100 nm. Claim 13 A seawater-sensitive degradable polymer material comprising a seawater-sensitive composite catalyst composition according to paragraph 4. Claim 14 A seawater-sensitive degradable polymer material according to claim 13, characterized in that the polymer component included in the seawater-sensitive degradable polymer material is one or more selected from the group comprising polyethylene, polypropylene, polystyrene, and polyvinyl chloride. Claim 15 A seawater-sensitive degradable polymer material according to claim 14, characterized in that the seawater-sensitive composite catalyst composition included in the seawater-sensitive degradable polymer material is included in an amount of 0.001 to 10 parts by weight based on 100 parts by weight of the total polymer material.

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