Catalyst for decomposing non-recalcitrant contaminants

Abstract

One embodiment of the present invention provides a catalyst for a pseudo-Fenton reaction applied with a core structure of iron oxychloride (FeOCl); and a shell structure of silicon dioxide (SiO2).

Description

Technology Field

[0001] The present invention relates to a pseudo-Fenton reaction catalyst comprising core-shell based particles in which FeOCl is the core and SiO2 is the shell for the efficient decomposition of recalcitrant organic matter, and more specifically, to a pseudo-Fenton reaction catalyst that 1) improves the structural stability of FeOCl in the presence of aqueous H2O2, and 2) allows for the control of the type and amount of radicals generated at the interface between FeOCl and SiO2. Background Technology

[0003] One of the mineralization technologies for wastewater containing recalcitrant / toxic organic substances such as phenols, endocrine disruptors, and pharmaceutical residues is the Fenton reaction, which decomposes organic substances by generating radical oxidizers within the wastewater. A typical Fenton reaction utilizes a water-soluble metal cation catalyst (M n+ ; M: Metal; n+: Formal charge; e.g. Fe 2+ ) hydrogen peroxide (H2O2) and homogeneous catalysis-based hydrogen peroxide heterogeneous cleavage (H2O2 heterolysis; H2O2+M n+ →OH - +OH+M (n+1)+ causes OH and M (n+1)+ to generate, or M (n+1)+ This reaction with hydrogen peroxide (H2O2+M (n+1)+ →OOH+H + +M n+ ) to generate OOH, or OOH undergoes deprotonation (OOH→O2) - +H + )become O2 - Generate OH / OOH / O2 -It is characterized by decomposing organic matter using . However, water-soluble metal cation catalysts applied to the Fenton reaction are single-use, and accordingly M n+ OH / OOH / O2 of the Fenton reaction using metal oxide-based catalysts highly dispersed on this surface - A pseudo-Fenton reaction has been proposed to generate while reusing metal oxide-based catalysts. Specifically, the pseudo-Fenton reaction is a heterogeneous catalysis-based hydrogen peroxide heterogeneous cleavage (H2O2+M n+ →OH - +OH+M (n+1)+ causes OH and M (n+1)+ Generate surface species, or M (n+1)+ Reaction of surface paper with hydrogen peroxide (H2O2+M (n+1)+ →OOH+H + +M n+ ) to generate OOH and M n+ Reduced to surface species, or OOH undergoes deprotonation (OOH→O2) - +H + )become O2 - Generate OH / OOH / O2 - It is characterized by decomposing organic matter using [it].

[0004] Recently, cases of applying FeOCl as a catalyst for pseudo-Fenton reactions have been reported, which is due to the Fe contained in FeOCl. 2+ / Fe 3+ Surface species are OH / OOH / O2 - External Fe 4+ =O surface species and singlet O2( 1 This is because it can generate O2) with high efficiency. Specifically, Fe 2+ Surface species react with OOH (Fe 2+ +OOH→Fe 4+ =O+OH) to make Fe 4+ =O generates surface species and OH, and Fe 3+ Surface species are O2 -Reaction with (Fe 3+ +O2 - →Fe 2+ + 1 (O2) and Fe 2+ Surface species and 1 It generates O2. Importantly, as inferred from the above reaction equations, the Fe inherent in FeOCl in the presence of aqueous H2O2 2+ Surface species are OH and Fe 4+ Promotes the formation of =O and the Fe inherent in FeOCl 3+ Surface species are OOH, O2 - and 1 While it promotes the generation of O2, no experimental examples have been reported that control the relative amount of its generation. Furthermore, while the high-efficiency degradation ability of FeOCl of recalcitrant organic substances in the presence of aqueous H2O2 and related examples have been frequently reported, the instability of FeOCl in aqueous solutions, such as Fe 2+ / Fe 3+ or Cl - There are no reported examples of improving the structural collapse of FeOCl caused by severe leaching. The problem to be solved

[0006] The technical problem that the present invention aims to solve is the Fe inherent in FeOCl. 2+ / Fe 3+ By adjusting the component ratio of surface species, OH / Fe in the presence of aqueous H2O2 4+ =O or OOH / O2 - / 1 The purpose is to propose and provide a method for synthesizing a FeOCl core-SiO2 shell-based catalyst to control the amount of O2 generated while improving the structural collapse of FeOCl.

[0007] In addition, the present invention relates to the O of SiO2 in the interfacial domain existing between the FeOCl core and the SiO2 shell of an FeOCl core-SiO2 shell catalyst. 2-Fe of FeOCl from 3+ e as a surface species - It is transferred, and the Fe inherent in the FeOCl surface 2+ Increases the component ratio of surface species, and OOH / O2 in the presence of aqueous H2O2 - / 1 OH / Fe relative to O2 4+ The goal is to increase the amount of O generated.

[0008] In addition, the present invention relates to the O of SiO2 in the interfacial domain existing between the FeOCl core and the SiO2 shell of an FeOCl core-SiO2 shell catalyst. 2- The Fe of this FeOCl 2+ / Fe 3+ Interacting strongly with surface species, Fe 2+ / Fe 3+ Surface species or Cl - The purpose is to reduce the detachment of surface species and to increase the lifetime of the FeOCl core-SiO2 shell catalyst in the presence of aqueous H2O2.

[0009] The technical problems that the present invention aims to solve are not limited to those mentioned above, and other unmentioned technical problems will be clearly understood by those skilled in the art to which the present invention belongs from the description below. means of solving the problem

[0011] As a technical means to achieve the aforementioned technical problem, one aspect of the present invention provides a catalyst for a pseudo-Fenton reaction applied with a core structure of iron oxychloride (FeOCl); and a shell structure of silicon dioxide (SiO2).

[0012] In an embodiment of the present invention, one or more of the core structure of the catalyst particle, iron oxychloride (FeOCl), or the shell structure, silicon dioxide (SiO2) may be characterized as having a crystalline or porous structure.

[0013] The catalyst particles are characterized by having a diameter of 0.1 nm to 500 μm.

[0014] The silicon dioxide (SiO2) in the shell structure of the catalyst particles may be characterized in that it is in an amount of 0.1 to 50 parts by weight per 100 parts by weight of iron oxychloride (FeOCl) in the core structure.

[0015] It may be characterized by causing a pseudo-Fenton reaction in the interfacial domain existing between the core structure iron oxychloride (FeOCl) and the shell structure silicon dioxide (SiO2).

[0016] The above-mentioned pseudo-Fenton reaction may be characterized by occurring under conditions of an aqueous solution containing hydrogen peroxide (H2O2).

[0017] The pH of the aqueous solution containing the above hydrogen peroxide (H2O2) is 2 to 10, and the concentration of hydrogen peroxide (H2O2) is 10 -5 mol / L to 10 5 It may be characterized by being mol / L.

[0018] O of silicon dioxide (SiO2) in the interfacial domain existing between core-structured iron oxychloride (FeOCl) and shell-structured silicon dioxide (SiO2) 2- From iron oxychloride (FeOCl) Fe 3+ electrons as surface species (e - ) is transferred, and the Fe inherent on the surface of iron oxychloride 2+ The component ratio of surface species is Fe 3+ It may be characterized by being larger than the component ratio of surface species.

[0019] In the interfacial domain existing between core-structured iron oxychloride (FeOCl) and shell-structured silicon dioxide (SiO2) * OOH / O2 *- / 1 Large compared to O2 production * OH / Fe 4+ It may be characterized by providing the amount of =O generated.

[0020] O of silicon dioxide (SiO2) in the interfacial domain existing between core-structured iron oxychloride (FeOCl) and shell-structured silicon dioxide (SiO2) 2- The Fe of this iron oxychloride (FeOCl) 2+ / Fe 3+ Interacting strongly with surface species, Fe 2+ / Fe 3+ Surface species or Cl - It may be characterized by a reduction in the abscission of surface species.

[0022] Another aspect of the present invention provides a method for manufacturing a catalyst for a pseudo-Fenton reaction, comprising the steps of: synthesizing a core structure iron oxychloride (FeOCl) (S100); and synthesizing a shell structure silicon dioxide (SiO2) that encapsulates the core structure iron oxychloride (FeOCl) (S200).

[0024] Another aspect of the present invention provides a method for removing non-degradable organic matter from wastewater, comprising the steps of: preparing a catalyst for a pseudo-Fenton reaction according to claim 1; and introducing said catalyst into wastewater containing non-degradable or toxic organic matter to perform a pseudo-Fenton reaction. Effects of the invention

[0026] The catalysts proposed in the present invention can be applied to the oxidative decomposition of sewage / wastewater, residual water-soluble pharmaceuticals, water-soluble environmental hormones, and chemical warfare agents.

[0027] According to one embodiment of the present invention, in the interfacial domain existing between the FeOCl core and the SiO2 shell of the FeOCl core-SiO2 shell catalyst, O of SiO2 2- Fe of FeOCl from 3+ e as a surface species - It is transferred, and the Fe inherent in the FeOCl surface 2+ Increases the component ratio of surface species, and OOH / O2 in the presence of aqueous H2O2 - / 1 OH / Fe relative to O2 4+ = Can increase the amount of O generated.

[0028] In addition, according to one embodiment of the present invention, in the interfacial domain existing between the FeOCl core and the SiO2 shell of the FeOCl core-SiO2 shell catalyst, O of SiO2 2- The Fe of this FeOCl 2+ / Fe 3+ Interacting strongly with surface species, Fe in the presence of aqueous H2O2 2+ / Fe 3+ Surface species or Cl - It can reduce the abscission of surface species.

[0029] In other words, the FeOCl core-SiO2 shell catalyst of the present invention (Example) can significantly avoid the phenomenon of catalyst particle detachment / structural collapse that occurs during the decomposition of recalcitrant organic substances in the presence of H2O2 in an aqueous phase compared to the FeOCl core (Comparative Example), and the decomposition performance of recalcitrant organic substances decreases less even after multiple catalyst uses, thereby having the effect of significantly extending the catalyst life.

[0030] The effects of the present invention are not limited to the effects described above, and should be understood to include all effects that can be inferred from the composition of the invention described in the description or claims of the present invention. Brief explanation of the drawing

[0032] Figure 1 is a high-resolution transmission electron microscopy (HRTEM) image of catalysts synthesized according to Comparative Example 1 and Example 1 of the present invention. FIG. 2 shows the acetaminophen decomposition reaction of the catalysts synthesized according to Comparative Example 1 and Example 1 of the present invention before (as-synthesized) and after (post the 1) the first decomposition reaction. st cycle), after the second decomposition reaction (post the 2 ndcycle), after the third decomposition reaction (post the 3 rd This is a graph showing the X-ray diffraction (XRD) pattern results of the cycle. FIG. 3 is a graph showing X-ray photoelectron spectra in the Fe 2p region of catalysts synthesized according to Comparative Example 1 and Example 1 of the present invention. FIG. 4 is an schematic diagram showing the types and formation pathways of long-lived adducts that appear during electron paramagnetic resonance (EPR) spectroscopy experiments in the presence of H2O2 and a radical trapping agent (5,5-dimethyl-1-pyrroline N-oxide (DMPO) or 2,2,6,6-tetramethyl piperidine (TEMP)) of catalysts synthesized according to Comparative Example 1 and Example 1 of the present invention. Figure 5 is a graph showing electron paramagnetic resonance (EPR) spectra of catalysts synthesized according to Comparative Example 1 and Example 1 of the present invention in the presence of H2O2 and a radical trapping agent (5,5-dimethyl-1-pyrroline N-oxide (DMPO) or 2,2,6,6-tetramethyl piperidine (TEMP)). FIG. 6 shows various radical quenchers of catalysts synthesized according to Comparative Example 1 and Example 1 of the present invention ( tert -Acetaminophen degradation reaction rate in the absence / presence of butyl alcohol or methanol (- r ACETAMINOPHEN It is a graph representing ). FIG. 7 shows the first to third acetaminophen decomposition reaction rates of catalysts synthesized according to Comparative Example 1 and Example 1 of the present invention (- rACETAMINOPHEN It is a graph representing ). Specific details for implementing the invention

[0033] The present invention will be described in more detail below. However, the present invention may be implemented in various different forms and is not limited by the embodiments described herein, and is defined only by the claims set forth below.

[0034] The present invention will be described below with reference to the attached drawings. However, the present invention may be implemented in various different forms and is therefore not limited to the embodiments described herein. Furthermore, in order to clearly explain the present invention in the drawings, parts unrelated to the explanation have been omitted, and similar parts throughout the specification have been given similar reference numerals.

[0035] Throughout the specification, when it is stated that a part is "connected (connected, in contact, combined)" with another part, this includes not only cases where they are "directly connected," but also cases where they are "indirectly connected" with other members interposed between them. Furthermore, when it is stated that a part "includes" a certain component, this means that, unless specifically stated otherwise, it does not exclude other components but rather allows for the inclusion of additional components.

[0036] The terms used herein are merely for describing specific embodiments and are not intended to limit the invention. Singular expressions include plural expressions unless the context clearly indicates otherwise. In this specification, terms such as “comprising” or “having” are intended to indicate the presence of the features, numbers, steps, actions, components, parts, or combinations thereof described in the specification, and should be understood as not precluding the existence or addition of one or more other features, numbers, steps, actions, components, parts, or combinations thereof.

[0038] The first aspect of the present invention provides a catalyst for a pseudo-Fenton reaction applied with a core structure of iron oxychloride (FeOCl); and a shell structure of silicon dioxide (SiO2).

[0040] Hereinafter, a catalyst for a pseudo-Fenton reaction according to the first aspect of the present invention will be described in detail.

[0041] In one embodiment of the present invention, one or more of the core structure of the catalyst particle, iron oxychloride (FeOCl), or the shell structure, silicon dioxide (SiO2) may have a crystalline or porous structure. The catalyst particle has a porous structure, wherein the shell structure of silicon dioxide (SiO2) may have a mesoporous structure.

[0042] In one embodiment of the present invention, through Figure 1, which shows a high-resolution transmission electron microscopy (HRTEM) image showing the structure of the catalyst particles, it can be observed that the core structure of iron oxychloride (FeOCl) or the shell structure of silicon dioxide (SiO2) has crystallinity, and the catalyst particles may have a diameter of 0.1 nm to 500 μm.

[0043] In one embodiment of the present invention, the silicon dioxide (SiO2) in the shell structure of the catalyst particle may be in an amount of 0.1 to 50 parts by weight per 100 parts by weight of iron oxychloride (FeOCl) in the core structure. If the amount is less than the above-described range, the O of SiO2 in the interfacial domain existing between the FeOCl core and the SiO2 shell 2- The Fe of this FeOCl 2+ / Fe 3+ It may not interact strongly with surface species, and thus Fe in the presence of aqueous H2O2 2+ / Fe 3+ Surface species or Cl - It may not reduce the detachment of surface species. Furthermore, if the aforementioned range is exceeded, the supply (diffusion) of H2O2 from the SiO2 shell to the surface of the FeOCl core may not be smooth, and consequently, OH / Fe 4+ The amount of O generated may not be significant.

[0044] In one embodiment of the present invention, a pseudo-Fenton reaction may occur in the interfacial domain existing between the core structure iron oxychloride (FeOCl) and the shell structure silicon dioxide (SiO2).

[0045] In one embodiment of the present invention, the pseudo-Fenton reaction may occur under conditions of an aqueous solution containing hydrogen peroxide (H2O2), wherein the pH of the aqueous solution containing hydrogen peroxide (H2O2) is 2 to 10 and the concentration of hydrogen peroxide (H2O2) is 10 -5 mol / L to 10 5 It could be mol / L.

[0046] In one embodiment of the present invention, in the interfacial domain existing between a core structure iron oxychloride (FeOCl) and a shell structure silicon dioxide (SiO2), O of silicon dioxide (SiO2) 2- From iron oxychloride (FeOCl) Fe 3+ electrons as surface species (e - ) is transferred, and the Fe inherent on the surface of iron oxychloride 2+ The component ratio of surface species is Fe 3+ It may be larger than the component ratio of surface species.

[0047] In one embodiment of the present invention, OOH / O2 in the interfacial domain existing between a core structure iron oxychloride (FeOCl) and a shell structure silicon dioxide (SiO2). - / 1 Large OH / Fe ratio relative to O2 production 4+It may provide the amount of =O generated.

[0048] In one embodiment of the present invention, according to one embodiment of the present invention, the pseudo-Fenton reaction is,

[0049] (1) Fe 2+ Heterogeneous cleavage of hydrogen peroxide in surface species (H2O2+Fe 2+ →OH - +OH+Fe 3+ OH and Fe by ) 3+ Step of generating surface paper;

[0050] (2) Fe 3+ Surface paper reacts with hydrogen peroxide (H2O2+Fe 3+ →OOH+H + +Fe 2+ ) to generate OOH and Fe 2+ Step of reduction to surface species;

[0051] (3) OOH is deprotonated (OOH→O2 - +H + )become O2 - Step of generating;

[0052] (4) Fe 2+ Reaction of surface paper OOH (Fe 2+ +OOH→Fe 4+ =O+OH) to make Fe 4+ = A step of generating O surface species and OH; and

[0053] (5)Fe 3+ Surface paper O2 - Reaction with (Fe 3+ +O2 - →Fe 2+ + 1 (O2) and Fe 2+ Surface species and 1 Step of generating O2;

[0054] It may include, but Fe 3+ Large Fe compared to surface species 2+ Due to the surface species component ratio, OOH / O2 - / 1 OH / Fe relative to O2 4+= The amount of O generated can be large.

[0055] Conversely, according to one comparative example of the present invention, the FeOCl catalyst surface that does not contain silicon dioxide (SiO2) with a shell structure is compared to the FeOCl core-SiO2 shell catalyst surface of one embodiment. 3+ The component ratio of surface species is Fe 2+ It can be larger than the component ratio of surface species.

[0056] According to one comparative example of the present invention, a pseudo-Fenton reaction can occur even on the surface of an FeOCl catalyst that does not contain silicon dioxide (SiO2) with a shell structure in the presence of aqueous hydrogen peroxide (H2O2).

[0057] According to one comparative example of the present invention, the pseudo-Fenton reaction of the FeOCl catalyst is,

[0058] (1) Fe 2+ Heterogeneous cleavage of hydrogen peroxide in surface species (H2O2+Fe 2+ →OH - +OH+Fe 3+ OH and Fe by ) 3+ Step of generating surface paper;

[0059] (2) Fe 3+ Surface paper reacts with hydrogen peroxide (H2O2+Fe 3+ →OOH+H + +Fe 2+ ) to generate OOH and Fe 2+ Step of reduction to surface species;

[0060] (3) OOH is deprotonated (OOH→O2 - +H + )become O2 - Step of generating;

[0061] (4) Fe 2+ Reaction of surface paper OOH (Fe 2+ +OOH→Fe 4+ =O+OH) to make Fe 4+= A step of generating O surface species and OH; and

[0062] (5)Fe 3+ Surface paper O2 - Reaction with (Fe 3+ +O2 - →Fe 2+ + 1 (O2) and Fe 2+ Surface species and 1 Step of generating O2;

[0063] It may include, but Fe 2+ Large Fe compared to surface species 3+ Due to the surface species component ratio, OH / Fe 4+ = O vs OOH / O2 - / 1 The amount of O2 generated can be large.

[0064] In one embodiment of the present invention, in the interfacial domain existing between a core structure iron oxychloride (FeOCl) and a shell structure silicon dioxide (SiO2), O of silicon dioxide (SiO2) 2- The Fe of this iron oxychloride (FeOCl) 2+ / Fe 3+ Interacting strongly with surface species, Fe 2+ / Fe 3+ Surface species or Cl - The detachment of surface species is reduced, and as a result, the life of the FeOCl core-SiO2 shell catalyst of one embodiment of the present invention may be increased in the presence of aqueous hydrogen peroxide (H2O2).

[0065] According to one comparative example of the present invention, the FeOCl catalyst surface that does not contain silicon dioxide (SiO2) with a shell structure is compared to the FeOCl core-SiO2 shell catalyst surface of one embodiment. 2+ / Fe 3+Surface species or Cl - The detachment of surface species can be significant, and the lifespan of the FeOCl catalyst can be severely reduced in the presence of aqueous hydrogen peroxide (H2O2).

[0067] A second aspect of the present invention provides a method for manufacturing a catalyst for a pseudo-Fenton reaction, comprising the steps of: synthesizing a core structure iron oxychloride (FeOCl) (S100); and synthesizing a shell structure silicon dioxide (SiO2) that encapsulates the core structure iron oxychloride (FeOCl) (S200).

[0068] Detailed descriptions of parts overlapping with the first aspect of the present invention have been omitted, but the description of the first aspect of the present invention may be applied in the same way even if such description is omitted in the second aspect.

[0070] A third aspect of the present invention provides a method for removing non-degradable organic matter from wastewater, comprising the steps of: preparing a catalyst for a pseudo-Fenton reaction according to claim 1; and introducing said catalyst into wastewater containing non-degradable or toxic organic matter to perform a pseudo-Fenton reaction.

[0071] Although detailed descriptions of parts overlapping with the first and second aspects of the present invention have been omitted, the descriptions of the first and second aspects of the present invention may be applied in the same way even if such descriptions are omitted in the third aspect.

[0073] Hereinafter, embodiments of the present invention are described in detail so that those skilled in the art can easily implement the invention. However, the present invention may be embodied in various different forms and is not limited to the embodiments described herein.

[0075] Comparative Example 1: Preparation of FeOCl Catalyst

[0076] 1.0g of FeCl36H2O in 1L min -1 An FeOCl catalyst was synthesized by thermal decomposition at 230°C for 3 hours under an Ar atmosphere, followed by lowering to 25°C, rinsing with 300 mL of acetone, and drying at 25°C under a vacuum atmosphere, and this was named Comparative Example 1.

[0078] Example 1: FeOCl core-SiO 2 shell(FeOCl-SiO 2 Preparation of catalysts

[0079] 0.125 g of FeOCl and 0.6 g of cetyltrimethylammonium bromide (CTAB) from Comparative Example 1 were added to 50 mL of distilled water and stirred at 25°C for 30 minutes. To the synthesis intermediate, 0.2 mL of 2.0 M NaOH aqueous solution, 25 μL of (3-aminopropyl) triethoxysilane (APTMS), and 1.5 mL of ethyl acetate were added and stirred at 25°C for 30 minutes, then stirred at 70°C for 3 hours. Afterward, 15 μL of 37 wt% HCl aqueous solution was added and stirred at 70°C for 1 hour. After lowering the temperature to 25°C, the mixture was centrifuged to isolate the solid product. The solid product was rinsed with 50 mL of ethanol and dried at 25°C under a vacuum atmosphere to synthesize an FeOCl core-SiO2 shell catalyst (named FeOCl-SiO2) and named Example 1.

[0080] Figure 1 shows the morphology of FeOCl and FeOCl-SiO2 catalyst particles synthesized according to Comparative Example 1 and Example 1 of the present invention. As shown in Figure 1, the catalyst particles have a size of hundreds to thousands of nanometers, and it can be seen that the FeOCl in Example 1 is encapsulated by SiO2. To analyze the porosity inherent in the morphology of the catalyst particles, N2 physisorption experiments were conducted, and their BET surface area and BJH pore volume were evaluated. The catalyst particles are 0.1 cm 3 g -1 It has a BJH pore volume, which means that the catalyst particles possess a porous morphology. In addition, the FeOCl of Comparative Example 1 is 6.1m 2 g -1 Although the relatively small BET surface area is [unclear], the FeOCl-SiO2 of Example 1 is 34.9 m² 2 g -1 It can be seen that it has a relatively large BET surface area, which is due to the larger mesopore size of the SiO2 shell compared to the FeOCl core of Example 1.

[0081] Figure 2 shows the XRD patterns of FeOCl and FeOCl-SiO2 catalyst particles synthesized according to Comparative Example 1 and Example 1 of the present invention. As shown in Figure 2, it can be seen that the catalysts of Comparative Example 1 and Example 1 contain an orthorhombic FeOCl crystalline phase. However, in the XRD analysis of Example 1, the crystalline phase of the SiO2 shell is not observed, which means that the SiO2 shell is amorphous, which is consistent with the absence of lattice fringes in the SiO2 morphology shown in Figure 1.

[0082] Figure 3 shows the XP spectra in the Fe 2p region of FeOCl and FeOCl-SiO2 catalyst particles synthesized according to Comparative Example 1 and Example 1 of the present invention, where the XP spectrum of each catalyst is deconvolved to show a total of six sub-bands. Specifically, in the case of FeOCl of Comparative Example 1, the binding energies at the maximum intensity of each of the six sub-bands are 711.0 eV, 711.7 eV, 717.3 eV, 723.8 eV, 725.7 eV, and 730.6 eV, respectively, which are Fe 2p 3 / 2 From Fe 2+ , Fe 2P 3 / 2 From Fe 3+ , Fe 2P 3 / 2 from satellite, Fe 2P 1 / 2 From Fe 2+ , Fe 2P 1 / 2 From Fe 3+ , Fe 2P 1 / 2 In this context, it refers to a satellite. On the other hand, in the case of FeOCl-SiO2 of Example 1, the binding energies at the maximum intensity of each of the six sub-bands are 710.8 eV, 711.5 eV, 717.3 eV, 723.6 eV, 725.5 eV, and 730.6 eV, respectively, which are Fe 2P 3 / 2 From Fe 2+ , Fe 2P 3 / 2 From Fe 3+ , Fe 2P 3 / 2 from satellite, Fe 2P 1 / 2 From Fe 2+ , Fe 2P 1 / 2 From Fe 3+ , Fe 2P 1 / 2 It means satellite. Fe 2+The component ratio of surface species is higher in FeOCl-SiO2 of Example 1 (41.6%) compared to FeOCl of Comparative Example 1 (26.2%), which is due to the O of SiO2 in the interfacial domain existing between the FeOCl core and the SiO2 shell of FeOCl-SiO2. 2- Fe of FeOCl from 3+ e as a surface species - It means that is transmitted. Also, Fe 2+ / Fe 3+ At the maximum intensity of the sub-bands, the binding energies of FeOCl-SiO2 in Example 1 are smaller than those of FeOCl in Comparative Example 1, which is due to the O of SiO2 in the interfacial domain existing between the FeOCl core and the SiO2 shell of FeOCl-SiO2. 2- The Fe of this FeOCl 2+ / Fe 3+ It means that it interacts strongly with surface species.

[0083] FIG. 4 shows adducts that can be formed in the presence of catalyst particles synthesized according to Comparative Example 1 or Example 1 of the present invention, water-soluble H2O2, and radical trapping agents such as DMPO or TEMP, and their formation pathways. In the case of OH, it combines with DMPO to form a DMPO-OH adduct (black square), and OOH / O2 - In this case, it combines with DMPO to form a DMPO-OOH adduct (red circle). Additionally, the DMPO-OH adduct undergoes an oxidation process to form HDMPO, whereby HDMPO combines with OH to form an HDMPO-OH adduct (green square), and 1 O2 combines with TEMP to form TEMP- 1 It forms an O2 adduct (blue diamond).

[0084] FIG. 5 shows the EPR spectra of the reaction solution obtained by adding 0.1 g of the catalyst synthesized according to Comparative Example 1 or Example 1 of the present invention, 2.6 mmol H2O2, and 0.7 mmol DMPO (or 0.5 mmol TEMP) to 0.5 mL of distilled water, stirring with a vortex at 25°C for 3 minutes to obtain a reaction mixture, and filtering the mixture. Importantly, DMPO-OH, DMPO-OOH, HDMPO-OH, or TEMP- 1 EPR spectra were simulated to analyze the presence and relative component amounts of O2 adducts. In the presence of aqueous H2O2 and DMPO, the catalysts of Comparative Example 1 and Example 1 include DMPO-OH (black square), DMPO-OOH (red circle), and HDMPO-OH (green square), which indicates that the catalyst particles of Comparative Example 1 and Example 1 [produce] OH, OOH, and O2 in the presence of aqueous H2O2. - This means forming. In the case of the relative component amount of DMPO-OH, FeOCl-SiO2 (78.0%) in Example 1 is larger than FeOCl (28.1%) in Comparative Example 1, which means that FeOCl-SiO2 is Fe relative to FeOCl. 2+ Since the content of surface species is richer, H2O2+Fe 2+ →OH - +OH+Fe 3+ This is because it activates better. In addition, regarding the relative component amount of DMPO-OOH, FeOCl in Comparative Example 1 (21.9%) is larger than FeOCl-SiO2 in Example 1 (4.3%), which indicates that FeOCl is higher than FeOCl-SiO2. 3+ Since the content of surface species is richer, H2O2+Fe 3+ →OOH+H + +Fe 2+ and OOH→O2 - +H + This is because it activates it more effectively.

[0085] On the other hand, in the presence of H2O2 and TEMP, the FeOCl of Comparative Example 1 is TEMP- 1 While it forms an O2 adduct (blue diamond), the FeOCl-SiO2 of Example 1 is TEMP- 1 It does not form an O2 adduct. This is because FeOCl is Fe relative to FeOCl-SiO2. 3+ Since the content of surface species is richer, Fe 3+ +O2 - →Fe 2+ + 1 This is because it effectively activates O2, and FeOCl-SiO2 is Fe 2+ Surface species make up the majority, and trace amounts of Fe inherent in FeOCl-SiO2 3+ Surface species are H2O2+Fe 3+ →OOH+H + +Fe 2+ by Fe 2+ This is because it is reduced to a surface species.

[0086] That is, the EPR spectroscopy results in Fig. 5 show that the FeOCl surface of Comparative Example 1 is Fe 3+ Surface species > Fe 2+ Proving that it possesses the characteristics of a surface species, and OOH / O2 in the presence of water-soluble H2O2 - / 1 Demonstrating that it promotes the formation of O2, the FeOCl-SiO2 surface of Example 1 is Fe 3+ surface species <Fe 2+ Proving that it possesses the characteristics of a surface species, and OH / Fe in the presence of water-soluble H2O2 4+ Proves that it promotes the formation of =O.

[0087] Hereinafter, the performance of a pseudo-Fenton reaction using the catalysts of Comparative Example 1 to Example 1 will be described with reference to FIGS. 6 to 7.

[0089] Experimental Example 1: Acetaminophen Decomposition Using a Pseudo-Fenton Reaction I

[0090] Reaction experiments are performed using Comparative Example 1 to Example 1 as catalysts, and using hydrogen peroxide (H2O2) dissolved in an aqueous solution and acetaminophen, a recalcitrant organic substance, as organic materials. 0.2 g of catalyst and 100 mL of aqueous solution are used as the reaction solution, and the reaction experiments are carried out at 25°C and pH 7. The amount of H2O2 used during the reaction is 30 mmol, and the amount of acetaminophen (N ACETAMINOPHEN, 0 ) is 0.007 mmol. The pseudo-first-order reaction fitting graph (pseudo-1) obtained through the conversion rate of acetaminophen obtained in the above experiment st -order kinetic fitting, -ln(C ACETAMINOPHEN / C ACETAMINOPHEN, 0 The slope of ) VS. time) is the rate constant of the reaction in which acetaminophen is decomposed ( k APP , min -1 It is the same as ). of each catalyst k APP in N ACETAMINOPHEN, 0 Multiply by (0.007 mmol) and divide by the amount of catalyst used (0.2 g) to obtain the initial acetaminophen decomposition reaction rate (-r ACETAMINOPHEN , mol ACETAMINOPHEN g CAT -1 min -1 ) was calculated and is shown in FIG. 6. Referring to FIG. 6, -r of Comparative Example 1 ACETAMINOPHEN is 5.7 mol ACETAMINOPHEN g CAT -1 min -1 -r of Example 1 ACETAMINOPHEN Value (1.6 mol ACETAMINOPHEN g CAT -1 min -1It is 3.6 times larger compared to ). On the other hand, referring to the EPR spectroscopy experiment in Fig. 5, the amount of OH generated in FeOCl of Comparative Example 1 (DMPO-OH: 28.1%) is approximately 2.8 times smaller than that of FeOCl-SiO2 of Example 1 (DMPO-OH: 78.0%). This implies that OH is not the major radical species causing the degradation of acetaminophen in the presence of aqueous H2O2 and Comparative Example 1 or Example 1. Furthermore, OH, OOH, and O2 - The redox potentials of are 2.7V, 1.8V, and -0.2V, respectively, and O2 - The secondary reaction rate constant for the degradation of acetaminophen is 0M -1 sec -1 This is because the major radical species causing the degradation of acetaminophen in the presence of aqueous H2O2 and Comparative Example 1 or Example 1 are OOH and O2 - It means that it is not. That is, the above -r ACETAMINOPHEN The values ​​are the major radical species that cause the degradation of acetaminophen in the presence of aqueous H2O2 and Comparative Example 1 or Example 1. 1 O2 or Fe 4+ Proves that =O.

[0091] Perform the experiment under the same conditions as the above acetaminophen degradation reaction experiment, provided that OH and before the reaction begins 1 O2 / Fe 4+ =O is deradicalized, but the second-order reaction rate constants are different tert -r obtained after adding 60 mmol of -butyl alcohol or methanol ACETAMINOPHEN The values ​​are shown in Figure 6. tert -OH of butyl alcohol / methanol and 1 O2 / Fe 4+ The second-order reaction rate constant for deradicalizing O is 5.0 x 10⁻⁶ 8 -1.0X10 9 M -1 sec-1 and 5.0X10 2 -4.0X10 3 M -1 sec -1 is. -r obtained from the acetaminophen degradation reaction experiments of Comparative Example 1. ACETAMINOPHEN In the case of the values, tert -r in the presence of -butyl alcohol / methanol ACETAMINOPHEN The values ​​are tert -r in the absence of -butyl alcohol / methanol ACETAMINOPHEN It is 76-86% relative to the value. This is because, in the acetaminophen degradation reaction experiments of Comparative Example 1, the major radical causing the degradation of acetaminophen is not OH. 1 O2 / Fe 4+ Proves that =O.

[0092] On the other hand, Example 1 is in the presence of aqueous H2O2 as shown in FIG. 5 1 Since the generation of O2 is absent, Fe 4+ =O must act as a major radical causing the degradation of acetaminophen. However, the mesopores of the SiO2 shell, which is a component of Example 1, contain Fe present in the FeOCl core 4+ Since =O restricts the accessibility of surface species to bulky acetaminophen, OH can act as a factor causing the degradation of acetaminophen. Accordingly, tert -Fe in the presence of butyl alcohol or methanol 4+ =O The loss of OH groups, which have a stronger tendency to non-radicalize compared to surface species, may be promoted, and ultimately, the degradation of acetaminophen may be significantly delayed, and -r ACETAMINOPHEN The values ​​may become significantly smaller. The hypotheses described above are based on the -r obtained from the acetaminophen degradation reaction experiments of Example 1. ACETAMINOPHEN This is proven by the values, specifically of Example 1. tert -r in the presence of -butyl alcohol / methanol ACETAMINOPHEN The values ​​are tert-r in the absence of -butyl alcohol / methanol ACETAMINOPHEN The value is 36-38%, which is significantly smaller compared to 76-86% of Comparative Example 1 above. The results of this reaction experiment suggest that by improving the mesoporousness of the SiO2 shell inherent in the FeOCl-SiO2 of Example 1, the Fe of bulky acetaminophen 4+ =O It is suggested that it is important to present a methodology to improve accessibility to surface species.

[0094] Experimental Example 2: Acetaminophen Decomposition Using Pheno-Fenton Reaction II

[0095] Reaction experiments are performed using Comparative Example 1 to Example 1 as catalysts, and using hydrogen peroxide (H2O2) dissolved in an aqueous solution and acetaminophen, a recalcitrant organic substance, as organic materials. 0.2 g of catalyst and 100 mL of aqueous solution are used as the reaction solution, and the reaction experiments are carried out at 25°C and pH 7. The amount of H2O2 used during the reaction is 30 mmol, and the amount of acetaminophen (N ACETAMINOPHEN, 0 ) is 0.007 mmol. First acetaminophen degradation reaction experiment (1 st After the completion of the cycle) the catalyst is rinsed with distilled water to obtain the second acetaminophen decomposition reaction experiment (2 nd A second acetaminophen degradation reaction experiment (2 cycle) was performed. In addition, a second acetaminophen degradation reaction experiment (2 nd After the completion of the cycle, the catalyst is rinsed with distilled water to obtain the catalyst, and dried at 70°C under a vacuum atmosphere to perform the third acetaminophen decomposition reaction experiment (3 rd A cycle) was performed. The pseudo-first-order reaction fitting graph (pseudo-1) obtained through the acetaminophen conversion rate obtained during the above experiment st -order kinetic fitting, -ln(C ACETAMINOPHEN / C ACETAMINOPHEN, 0 The slope of ) VS. time) is the rate constant of the reaction in which acetaminophen is decomposed (k APP , min -1 It is the same as ). of each catalyst k APP in N ACETAMINOPHEN, 0 Multiply by (0.007 mmol) and divide by the amount of catalyst used (0.2 g) to obtain the initial acetaminophen decomposition reaction rate (-r ACETAMINOPHEN , mol ACETAMINOPHEN g CAT -1 min -1 ) was calculated and is shown in FIG. 7. Referring to FIG. 7, the -r of the catalysts of Comparative Example 1 and Example 1 ACETAMINOPHEN The values ​​are 1 st cycle→2 nd cycle→3 rd It continuously decreases as the cycle progresses. This is consistent with the continuous decrease in peak intensity of the XRD patterns representing the bulk crystallinity of the catalyst particles of Comparative Example 1 and Example 1 observed in Fig. 2. In addition, referring to Fig. 7, 1 st cycle and 2 nd -r of Comparative Example 1 in the cycle ACETAMINOPHEN Value > -r of Example 1 ACETAMINOPHEN It was a value, but 3 rd -r of Comparative Example 1 and Example 1 in the cycle ACETAMINOPHEN The values ​​were similar. 1 st cycle and 2 nd -r of Comparative Example 1 observed in the cycle ACETAMINOPHEN -r of Example 1, which is below the values ACETAMINOPHEN The values ​​are the Fe of bulky acetaminophen limited by the mesoporous SiO2 shell inherent in Example 1. 4+ =O is attributed to accessibility to surface species. The results of these reaction experiments improve the mesoporousness of the SiO2 shell inherent in the FeOCl-SiO2 of Example 1, thereby improving the bulky acetaminophen Fe 4+ =O It is suggested that presenting a synthesis methodology to improve accessibility to surface species is important.

[0096] Nevertheless, the above -r ACETAMINOPHEN Judging from the trends of the values, 4 th -r of Comparative Example 1 from cycle ACETAMINOPHEN Value < -r of Example 1 ACETAMINOPHEN It is determined that the value can be realized, which demonstrates the enhanced stability / improved lifespan of Example 1 compared to Comparative Example 1 in the presence of aqueous H2O2. 1 st cycle / 2 nd cycle / 3 rd The amount of Fe and Si leached into the aqueous phase after cycling was analyzed using inductively coupled plasma (ICP) spectroscopy and is shown in Table 1. As shown in Table 1, the amount of leached Si in Example 1 was less than 0.1 mol%, which demonstrates the high stability of the SiO2 shell inherent in Example 1 against H2O2 in the aqueous phase. In addition, the amount of leached Fe in Example 1 (2.6-2.8 mol%) was significantly lower than that in Comparative Example 1 (2.9-25.4 mol%), which demonstrates the enhanced stability of Example 1 against H2O2 in the aqueous phase compared to Comparative Example 1.

[0097] Comparative Example 1 (FeOCl) Example 1 (FeOCl-SiO2) Amount of Fe removed (mol%) post the 1 st cycle 25.4 2.6 post the 2 nd cycle 2.8 2.7 post the 3 rd cycle 2.9 2.8 Amount of detached Si (mol%) post the 1 st cycle - <0.1 post the 2 nd cycle - <0.1 post the 3 rd cycle - <0.1

[0098] The foregoing description of the present invention is for illustrative purposes only, and those skilled in the art will understand that other specific forms can be easily modified without altering the technical spirit or essential features of the present invention. Therefore, the embodiments described above should be understood as illustrative in all respects and not restrictive. For example, each component described as a single unit may be implemented in a distributed manner, and components described as distributed may likewise be implemented in a combined form.

[0099] The scope of the present invention is defined by the claims set forth below, and all modifications or variations derived from the meaning and scope of the claims and equivalent concepts thereof should be interpreted as being included within the scope of the present invention.

Claims

Claim 1 A catalyst for a pseudo-Fenton reaction, characterized by being applied as iron oxychloride (FeOCl) with a core structure and silicon dioxide (SiO2) with a shell structure, and causing a pseudo-Fenton reaction in an interfacial domain existing between the iron oxychloride (FeOCl) with a core structure and silicon dioxide (SiO2) with a shell structure. Claim 2 A catalyst for a pseudo-Fenton reaction according to claim 1, characterized in that one or more of the core structure of the catalyst particle, iron oxychloride (FeOCl), or the shell structure, silicon dioxide (SiO2) has a crystalline or porous structure. Claim 3 A catalyst for a pseudo-Fenton reaction according to claim 1, characterized in that the catalyst particles have a diameter of 0.1 nm to 500 μm. Claim 4 A catalyst for a pseudo-Fenton reaction according to claim 1, characterized in that the silicon dioxide (SiO2) of the shell structure of the catalyst particles is in an amount of 0.1 to 50 parts by weight per 100 parts by weight of iron oxychloride (FeOCl) of the core structure. Claim 5 delete Claim 6 A catalyst for a pseudo-Fenton reaction according to claim 1, characterized in that the pseudo-Fenton reaction occurs under conditions of an aqueous solution containing hydrogen peroxide (H2O2). Claim 7 In claim 6, the pH of the aqueous solution containing hydrogen peroxide (H2O2) is 2 to 10, and the concentration of hydrogen peroxide (H2O2) is 10 -5 mol / L to 10 5 A catalyst for a pseudo-Fenton reaction characterized by having a mol / L ratio. Claim 8 In claim 1, O of silicon dioxide (SiO2) in the interfacial domain existing between the core structure iron oxychloride (FeOCl) and the shell structure silicon dioxide (SiO2). 2- From iron oxychloride (FeOCl) Fe 3+ electrons as surface species (e - ) is transferred, and the Fe inherent on the surface of iron oxychloride 2+ The component ratio of surface species is Fe 3+ A catalyst for a pseudo-Fenton reaction characterized by being greater than the component ratio of the surface species. Claim 9 In claim 1, OOH / O2 in the interfacial domain existing between the core structure iron oxychloride (FeOCl) and the shell structure silicon dioxide (SiO2). - / 1 Large OH / Fe ratio relative to O2 production 4+ A catalyst for a pseudo-Fenton reaction characterized by providing a production amount of =O. Claim 10 In claim 1, O of silicon dioxide (SiO2) in the interfacial domain existing between the core structure iron oxychloride (FeOCl) and the shell structure silicon dioxide (SiO2). 2- The Fe of this iron oxychloride (FeOCl) 2+ / Fe 3+ Interacting strongly with surface species, Fe 2+ / Fe 3+ Surface species or Cl - A catalyst for a pseudo-Fenton reaction characterized by reduced detachment of surface species. Claim 11 A method for preparing a catalyst for a Fenton-like reaction according to claim 1, comprising: a step (S100) of synthesizing iron oxychloride (FeOCl) with a core structure; and a step (S200) of synthesizing silicon dioxide (SiO2) with a shell structure that encapsulates the iron oxychloride (FeOCl) with a core structure. Claim 12 A method for removing non-degradable organic matter from wastewater, comprising: a step of preparing a catalyst for a pseudo-Fenton reaction according to claim 1; and a step of performing a pseudo-Fenton reaction by adding the catalyst and hydrogen peroxide (H2O2) to wastewater containing non-degradable or toxic organic matter.

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