Methods, systems, and compositions for oxidizing substrates

Abstract

Methods, systems, and compositions for oxidation are provided. The method includes combining a macrocyclic ligand and a metal complex catalyst, an electrolyte, a substrate, and water to form an aqueous composition. The method includes applying a voltage to the aqueous composition and oxidizing the substrate in the presence of a catalyst.

Description

[0001] Inventor: Matthew Mills Technical Field This invention relates to methods, systems, and compositions for oxidizing substrates. Background Technology

[0002] Electrochemical oxidation has been used to treat concentrated waste streams containing organic and inorganic compounds. However, typical electrochemical oxidation systems present challenges. Summary of the Invention

[0003] In one aspect, the present invention provides a method for oxidizing a substrate. The method includes combining a metal complex catalyst, an electrolyte, a substrate, and water to form an aqueous composition. The method further includes applying a voltage to the aqueous composition and oxidizing the substrate in the presence of a catalyst.

[0004] In another aspect, this disclosure provides aqueous compositions for oxidation.

[0005] It should be understood that the invention described in this specification is not limited to the embodiments summarized in the content of this invention. Various other aspects are described and illustrated herein. Attached Figure Description

[0006] The features and advantages of the embodiments, as well as the ways in which they are implemented, will become more apparent from the following description of the embodiments taken in conjunction with the accompanying drawings, and the embodiments will be better understood, wherein: Figure 1 This is a schematic diagram of an electrolytic cell according to the present invention; and Figure 2 The concentration of acetaminophen was measured by LC-MS / MS, and the data were plotted to measure the degradation rate.

[0007] In the various views, corresponding reference numerals denote corresponding parts. The examples described herein illustrate certain embodiments in one form, and such examples should not be construed as limiting the scope of the embodiments in any way. Detailed Implementation

[0008] Certain exemplary aspects of this disclosure will now be described to provide a comprehensive understanding of the principles of composition, function, manufacture, and use of the compositions and methods disclosed herein. One or more embodiments of these aspects are illustrated in the accompanying drawings. It will be understood by those skilled in the art that the compositions and methods specifically described herein are non-limiting exemplary aspects, and that the scope of the various embodiments of the invention is defined only by the claims. Features shown or described in conjunction with one exemplary aspect may be combined with features of other aspects. Such modifications and variations are intended to be included within the scope of the invention.

[0009] Typically, large amounts of electrolyte and high current densities have been used to oxidize substrates in waste streams via electrochemical reactions. However, these existing methods can be inefficient, costly, and may require extensive remediation of the waste stream. Therefore, the present invention provides methods, apparatus, and compositions for oxidizing substrates that can reduce reaction temperatures, electrolyte concentrations, oxidant requirements, current densities used, and / or electrode sizes.

[0010] A method for oxidizing a substrate according to the present invention may include combining a metal complex catalyst, an electrolyte, a substrate, and water to form an aqueous composition. Combining may include mixing the materials together in a container. In various embodiments, the catalyst, electrolyte, and / or substrate are first combined with water before being combined with other materials. For example, the substrate and / or electrolyte may be combined with water before the catalyst is added. Additional water may be added to the method if desired.

[0011] The substrate can be present in the waste stream, such as an aqueous waste stream. Aqueous waste streams can include textile dyeing wastewater, pharmaceutical waste streams, oil and gaseous waste streams, treatment streams, and / or other waste stream types. In various embodiments, at least a portion of the electrolyte can be present in the aqueous waste stream. Depending on the water content and / or conductivity of the aqueous waste stream, the combination may include adding a catalyst to the aqueous waste stream and optionally water and / or electrolyte.

[0012] The catalyst can be added in a certain amount to achieve a concentration of 10 nm to 100 μm catalyst in the aqueous composition, such as, for example, 20 nm to 50 μm, 100 nm to 50 μm, 0.5 μm to 50 μm catalyst, 0.5 μm to 25 μm catalyst, 0.5 μm to 25 μm catalyst, or 0.5 μm to 10 μm catalyst. The catalyst can be provided in the form of an aqueous composition, slurry, powder, granules, and / or tablets.

[0013] The catalyst may comprise four N-groups bonded to a metal. The N-groups are nitrogen-containing groups selected from the group consisting of amides, sulfonamides, and phosphoramides. The nitrogen in the N-groups may be directly bonded to the metal. In various embodiments, the N-groups comprise at least one nitrogen-containing group selected from the group consisting of sulfonamides and phosphoramides. In some embodiments, the catalyst may comprise a diamino-disulfonamide macrocyclic ligand and a metal complex and / or a tetrasulfonamide macrocyclic ligand and a metal catalyst. The catalyst may comprise catalysts as described in U.S. Patent 7,060,818 and / or U.S. Patent 10,926,248, the entire contents of which are incorporated herein by reference. The metal in the catalyst may be a transition metal, such as iron, manganese, cobalt, and / or copper. For example, the metal in the catalyst may be iron and / or manganese. In various embodiments, the catalyst may comprise at least one of the following structures 1-6: Structure 1

[0014] Structure 2

[0015] Structure 3

[0016] Structure 4

[0017] Structure 5

[0018] Structure 6

[0019] The amount of electrolyte added can make the conductivity of the aqueous composition reach 0.1 μS to 100 mS, for example 1 μS / cm to 50 mS / cm, 1 μS / cm to 3 mS / cm, 1 μS / cm to 2 mS / cm, 1 μS / cm to 1 mS / cm, 1 μS to 900 μS / cm, 5 μS / cm to 800 μS / cm, 25 μS / cm to 700 μS / cm, 20 μS / cm to 600 μS / cm, 50 μS / cm to 500 μS / cm, 50 μS / cm to 400 μS / cm, 50 μS / cm to 100 μS / cm, or 100 μS / cm to 400 μS / cm. In various embodiments, the electrolyte may be present in amounts from 10 mg / L to 5000 mg / L, such as 100 mg / L to 4000 mg / L, 500 mg / L to 3000 mg / L, or 1000 mg / L to 2500 mg / L. Conductivity can be measured using a conductivity meter, such as the Orion Star 212 benchtop conductivity meter from Thermo Fisher Scientific, Waltham, Massachusetts, USA.

[0020] The use of a catalyst can reduce the amount of electrolyte present during oxidation. For example, a catalyst can participate in the oxidation reaction by acting as a catalytic intermediate to facilitate the transfer of electrons from the working electrode to the substrate. The oxidizing catalyst can then oxidize the substrate.

[0021] Electrolytes may include salts, such as halides, sulfates, phosphates, nitrates, and / or carbonates. For example, electrolytes may include sodium chloride, sodium sulfate, and / or sodium phosphate. In various embodiments, the electrolyte may be sodium chloride, and the oxidant generated during oxidation may be chlorine, which may be converted to hypochlorite and / or hypochlorous acid. In some embodiments, the electrolyte may include sulfates, and the oxidant generated during oxidation may be peroxydisulfate. In various embodiments, other oxidants, such as ozone, hydrogen peroxide, and / or hydroxyl radicals, may be generated at the working electrode (e.g., anode, cathode) under electrochemical conditions. In various embodiments, oxidants may be generated during oxidation, and the oxidant may activate a catalyst, which then oxidizes the substrate.

[0022] The substrate can be added in an amount reaching a concentration of 0.001 mg / L to 100,000 mg / L in the aqueous composition, such as 1 mg / L to 10,000 mg / L, 5 mg / L to 1,000 mg / L, or 10 mg / L to 100 mg / L. The substrate may comprise an organic compound, such as a textile dye or an active pharmaceutical ingredient.

[0023] Water may be added in an amount that reaches a concentration of at least 50% by weight in the aqueous composition, based on the total weight of the composition, for example, at least 55% by weight, at least 60% by weight, at least 70% by weight, at least 80% by weight, or at least 90% by weight, all based on the total weight of the aqueous composition.

[0024] Optionally, additional reagents may be added to the aqueous composition to enhance its washing, dispersing, wetting, alkalinity, salinity, and / or buffering capabilities. For example, additional reagents may include wetting agents, surfactants, denaturants, cosolvents, and / or buffers.

[0025] The method may include applying a voltage to the aqueous composition and oxidizing the substrate in the presence of the catalyst in the aqueous composition. In various embodiments, the oxidized substrate may be decomposed, decolorized, detoxicated, or have its chemical and / or biological oxygen demand reduced for further substrate treatment and / or other chemical modifications. The method may be carried out as a batch, continuous, or semi-batch process.

[0026] The method may include introducing an aqueous composition into an electrolyzer, such as electrolyzer 100 shown in the figure. Electrolyzer 100 may include an anode 102 and a cathode 104, and a voltage may be applied to the anode 102 and cathode 104. An aqueous composition 106 may be contacted with the anode 102 and cathode 104. The anode 102 and cathode 106 may be electrically connected to a power source 108 (e.g., a DC power source). Depending on the configuration of electrolyzer 100, it may be configured to operate in an intermittent, continuous, or semi-continuous mode. For example, the aqueous composition 106 may be added to electrolyzer 100 in a single step, or a pump may be used to continuously circulate the aqueous composition through electrolyzer 100. The method may also include a series of electrode pairs through which the aqueous composition flows.

[0027] A voltage can be applied at a level sufficient to promote substrate oxidation, for example, a level sufficient to activate the catalyst and / or generate an oxidant from the electrolyte. A current can be applied to the aqueous composition to achieve a voltage greater than 0 to 500 mA / cm² in the aqueous composition. 2 Current density, for example, 1 mA / cm 2 Up to 100mA / cm 2 1mA / cm 2 Up to 50mA / cm 2 1 mA / cm 2 Up to 25 mA / cm 2 or 1 mA / cm 2 Up to 10 mA / cm 2 Current density is based on the current applied to the working electrode and the surface area of ​​the working electrode.

[0028] During the oxidation process, the aqueous composition can be subjected to a temperature range of 0°C to 95°C, for example, 5°C to 90°C, 5°C to 70°C, 5°C to 50°C, 10°C to 50°C, 10°C to 45°C, or 15°C to 45°C. The use of a catalyst can lower the oxidation temperature, which can reduce the energy requirement of the method.

[0029] During the oxidation process, the pH of the aqueous composition can be in the range of 4 to 13, such as 4 to 11, 4 to 10, 5 to 9, 5.5 to 8.5, 6 to 8, or 6.2 to 7.8.

[0030] In various embodiments, the aqueous composition is free of oxidant before voltage is applied, and any oxidant present can be generated by the applied voltage. "Free of oxidant" means that the aqueous composition contains no more than 0.1% by weight of oxidant, such as no more than 0.05% by weight, no more than 0.01% by weight, or no more than 0.001% by weight. The aqueous composition may not contain any intentionally added oxidant.

[0031] The present invention also provides an aqueous composition for oxidizing a substrate. The aqueous composition may comprise a catalyst, an electrolyte, and water.

[0032] Example This disclosure will be more fully understood by referring to the following embodiments, which provide illustrative and non-limiting aspects of the invention. It should be understood that the invention described in this specification is not necessarily limited to the embodiments described in this section.

[0033] Preparation method of aqueous composition Various aqueous compositions were prepared using different amounts of electrolyte and catalyst. For each aqueous composition, deionized water was added to a glass beaker equipped with a stir bar and placed on a stirring plate to provide constant mixing. Then, the electrolyte, the Orange II dye substrate (sodium 4-(2-hydroxy-1-naphthylazo)benzenesulfonate), and a metal complex catalyst (if present) were added and mixed together. The metal in the catalyst was iron. Orange II dye was used as a substitute for other substrates because quantifying the oxidation of Orange II dye is easier.

[0034] Electrolytic cell configuration An electrolytic cell is prepared for applying voltage to various aqueous compositions. According to... Figure 1 An electrolytic cell was configured, comprising placing a boron-doped diamond anode and a titanium-based cathode in a glass beaker containing the solution with a 13 mm electrode gap. The anode surface area is 8.1 cm². 2 The surface area of ​​the cathode is 19 cm². 2 The cathode and anode were connected to a three-electrode potentiostat to control and monitor the system voltage, system current, and the electrode (anode) potential of the reference Ag / AgCl electrode. The reference electrode was suspended in a glass beaker within 2 mm of the anode surface. The experiment was conducted in either potentiostat mode (controlling the anode potential) or current-constant mode (controlling the current).

[0035] Measurement Procedure At ambient temperature (e.g., 20°C ± 2°C), the aqueous composition was pumped from a glass beaker through an online UV-Vis spectrophotometer (UV-VIS Spec) at a flow rate of 100 mL / min using a peristaltic pump. It was then pumped through a 0.25 mL electrochemical cell, passing through a surface area of ​​4.5 cm². 2The anode was used. As the aqueous composition was pumped through the tank over 15 minutes, the UV-Vis spec measured the absorbance of the aqueous composition in the wavelength range of 200 to 600 nanometers (nm). The change in absorbance at 484 nm was used to infer the degradation of the Orange II dye using molar absorbance calculations governed by the Beer-Lambert law (also known as Beer's law).

[0036]

[0037] An aqueous composition consisting of 150 mL of 20 mM phosphate buffer (pH 7.9), 0.5 mg / L acetaminophen, and 0 or 1 µM catalyst was added to the electrochemical reactor. The electrochemical cell consisted of a 12 cm⁻¹ core. 2 The battery consists of a boron-doped diamond anode and a titanium cathode. The current density is set at 10 mA cm⁻¹. -2 The reaction mixture was stirred at 400 rpm using magnetic stirring. The concentration of acetaminophen was measured by LC-MS / MS, and data were plotted to measure the degradation rate, such as... Figure 2 As shown.

[0038] Various aspects of the invention according to this disclosure include, but are not limited to, those listed in the following numbered clauses.

[0039] Clause 1. A method for oxidizing a substrate, the method comprising: combining a macrocyclic ligand and a metal complex catalyst, an electrolyte, a substrate, and water to form an aqueous composition; and applying a voltage to the aqueous composition and oxidizing the substrate in the presence of the catalyst.

[0040] Clause 2. The method of Clause 1, wherein the electrolyte is added in an amount that provides a conductivity in the range of 0.1 μS / cm to 100 mS / cm in the aqueous composition.

[0041] Clause 3. The method of Clause 1, wherein the electrolyte is added in an amount to obtain a conductivity in the range of 50 μS / cm to 100 μS / cm in the aqueous composition.

[0042] Clause 4. The method of any one of Clauses 1-3, wherein the electrolyte comprises a salt.

[0043] Clause 5. The method of any one of Clauses 1-4, wherein the electrolyte comprises a halide, sulfate, phosphate, nitrate and / or carbonate.

[0044] Clause 6. The method of any one of Clauses 1-5, wherein the electrolyte comprises sodium chloride, sodium sulfate, sodium phosphate, or a combination thereof.

[0045] Clause 7. The method of any one of Clauses 1-6, wherein the substrate comprises an organic compound.

[0046] Clause 8. The method of any one of Clauses 1-7, wherein the substrate comprises an inorganic compound.

[0047] Clause 9. The method of any one of Clauses 1-8, wherein water is added in an amount that achieves a concentration of at least 50% by weight in the aqueous composition based on the total weight of the aqueous composition.

[0048] Clause 10. The method of any one of Clauses 1-9, wherein the catalyst is added in an amount that achieves a catalyst concentration in the range of 10 nM to 100 μM in the aqueous composition.

[0049] Clause 11. The method of any one of Clauses 1-10, wherein the catalyst is added in an amount that achieves a catalyst concentration in the range of 1 μM to 10 μM in the aqueous composition.

[0050] Clause 12. The method of any one of Clauses 1-11, wherein the catalyst comprises four N-groups bonded to a metal, and each N-group is selected from the group consisting of amides, sulfonamides and phosphoramides.

[0051] Clause 13. The method of Clause 12, wherein the catalyst comprises iron, manganese, cobalt, copper or a combination thereof as the metal.

[0052] Clause 14. The method of any one of Clauses 1-13, wherein the catalyst comprises at least one of the following structures: ; ; ; ; ;and .

[0053] Clause 15. The method of any one of Clauses 1-14 further comprises adding an additional reagent to the aqueous composition, wherein the additional reagent is selected from the group consisting of wetting agents, surfactants, denaturants, cosolvents and buffers.

[0054] Clause 16. The method of any one of Clauses 1-15, wherein the aqueous composition is free of oxidants prior to the application of the voltage.

[0055] Clause 17. The method of any one of Clauses 1-16, wherein during the oxidation, the pH of the aqueous composition is in the range of 4 to 13.

[0056] Clause 18. The method of any one of Clauses 1-17, wherein during the oxidation, the pH of the aqueous composition is in the range of 6 to 8.

[0057] Clause 19. The method of any one of Clauses 1-18, wherein during the oxidation, the aqueous composition is at a temperature in the range of 0°C to 95°C.

[0058] Clause 20. The method of any one of Clauses 1-19, wherein a voltage is applied to the aqueous composition to achieve a voltage greater than 0 to 500 mA / cm in the aqueous composition. 2 The current density within the range.

[0059] Clause 21. The method of any one of Clauses 1-20, wherein a voltage is applied to the aqueous composition to achieve a voltage greater than 0 mA / cm in the aqueous composition. 2 Up to 100mA / cm 2 The current density within the range.

[0060] Clause 22. The method of any one of Clauses 1-21, wherein a voltage is applied to the aqueous composition to achieve 1 mA / cm² in the aqueous composition. 2 Up to 10 mA / cm 2 The current density.

[0061] The method of any one of Clauses 23.1-22 further comprises introducing the aqueous composition into an electrolytic cell including an anode and a cathode, wherein the aqueous composition is configured to contact the anode and the cathode, and applying the voltage between the anode and the cathode such that the substrate is oxidized in the presence of the catalyst.

[0062] Clause 24. A system for the oxidation of a substrate, said system being configured to perform the method described in any one of Clauses 1-23.

[0063] Clause 25. A system for the oxidation of a substrate, said system comprising: an electrolytic cell including an anode and a cathode; and a catalyst comprising at least one of the following structures: ; ; ; ; ;and .

[0064] Throughout this specification, references to "various embodiments," "some embodiments," "one embodiment," or simply "embodiment" mean that a particular feature, structure, or characteristic described in connection with an embodiment is included in at least one embodiment. Therefore, phrases such as "in various embodiments," "in some embodiments," "in one embodiment," or "in an embodiment" appearing throughout this specification do not necessarily refer to the same embodiment. Furthermore, in one or more embodiments, particular features, structures, or characteristics can be combined in any suitable manner. Thus, a particular feature, structure, or characteristic shown or described in connection with one embodiment can be combined, in whole or in part, with features, structures, or characteristics of one or more other embodiments without limitation. Such modifications and variations are intended to be included within the scope of this embodiment.

[0065] In this specification, unless otherwise stated, all numerical parameters should be understood to begin and be modified in all cases by the term “about,” whereby the numerical parameters have inherent variability in the basic measurement techniques used to determine the parameter values. At least, and without attempting to limit the application of the doctrine of equivalence to the scope of the claims, each numerical parameter described herein should be interpreted at least according to the number of significant figures reported and by applying ordinary rounding techniques.

[0066] Furthermore, any numerical range described herein includes all subranges contained within the stated range. For example, the range “1-10” includes all subranges between the minimum value 1 and the maximum value 10 (inclusive), i.e., a minimum value equal to or greater than 1 and a maximum value equal to or less than 10. Any maximum numerical limit described in this specification is intended to include all lower numerical limits contained therein, and any minimum numerical limit described in this specification is intended to include all higher numerical limits contained therein. Therefore, the applicant reserves the right to amend this specification (including the claims) to expressly list any subranges contained within the expressly listed range. All ranges are described in this specification.

[0067] Unless otherwise stated, the grammatical articles “a,” “one,” and “the” used herein are intended to include “at least one” or “one or more,” even when “at least one” or “one or more” is explicitly used in certain circumstances. Therefore, the article is used here to refer to one or more (i.e., “at least one”) grammatical objects of the article. Furthermore, the use of singular nouns includes plural nouns, and the use of plural nouns includes singular nouns, unless the context of the usage requires otherwise.

[0068] Those skilled in the art will recognize that, for clarity of concept, the compositions, methods, and accompanying discussions described herein are used as examples, and various construction modifications may be considered. Therefore, as used herein, the specific embodiments illustrated and the accompanying discussions are intended to represent their more general category. Generally, the use of any particular sample is intended to represent its category, and the exclusion of specific components (e.g., operation), devices, and objects should not be considered limiting.

[0069] Although specific examples of the invention have been described above for illustrative purposes, it will be apparent to those skilled in the art that various changes may be made to the details of the invention without departing from the invention as defined in the appended claims. For example, various other ketones, glycol ethers, salts, alcohols, and additional components may be used in the cleaning fluid compositions of the present invention, in addition to those used in the examples.

[0070] Regarding the appended claims, those skilled in the art will understand that the operations described herein can generally be performed in any order. Furthermore, although various operational flows are presented in sequence, it should be understood that the various operations can be performed in a different order than those shown, or can be performed simultaneously. Examples of such alternating sequences may include overlapping, interleaved, interrupted, reordered, incremental, preparatory, supplementary, simultaneous, reverse, or other varied sequences, unless the context otherwise requires. Moreover, unless the context otherwise requires, terms such as “in response to,” “related to,” or other past tense adjectives are generally not intended to exclude such variations.

[0071] Although various examples have been described herein, many modifications, variations, substitutions, alterations, and equivalents of these examples are possible and will be apparent to those skilled in the art. Furthermore, where materials for certain components are disclosed, other materials may be used. Therefore, it should be understood that the foregoing description and the appended claims are intended to cover all such modifications and variations falling within the scope of the disclosed embodiments. The following claims are intended to cover all such modifications and variations.

[0072] Any patent, publication, or other disclosure incorporated herein by reference, in whole or in part, is incorporated only to the extent that the incorporated material does not conflict with any existing definitions, statements, or other disclosures set forth herein. Therefore, to the extent necessary, the disclosures expressly presented herein supersede any conflicting material incorporated herein by reference. Any material, or part thereof, deemed to be incorporated herein by reference but conflicting with any existing definitions, statements, or other disclosures set forth herein, will be incorporated only to the extent that the incorporated material does not conflict with any existing disclosures.

[0073] In summary, the numerous benefits arising from employing the concepts described herein have been described. For purposes of illustration and description, the above description of one or more embodiments has been given. It is not intended to be exhaustive or limiting to the precise forms disclosed. Modifications or variations are possible in accordance with the above teachings. One or more embodiments were chosen and described to illustrate principles and practical application, thereby enabling those skilled in the art to utilize various embodiments and make various modifications to suit a particular intended use. The claims filed herein are intended to define the entire scope.

[0074] While this disclosure provides descriptions of various specific aspects to illustrate different facets of the disclosure and / or its potential applications, it should be understood that various variations and modifications will occur to those skilled in the art. Therefore, the invention described herein should be understood to be at least as broad as claimed, and not more narrowly limited by the specific illustrative aspects provided herein.

Claims

1. A method for oxidizing a substrate, the method comprising: Macrocyclic ligands and metal complex catalysts, electrolytes, substrates, and water are combined to form aqueous compositions; and A voltage is applied to the aqueous composition, and the substrate is oxidized in the presence of the catalyst.

2. The method of claim 1, wherein the electrolyte is added in an amount that achieves a conductivity in the range of 0.1 μS / cm to 100 mS / cm in the aqueous composition.

3. The method of claim 1, wherein the electrolyte is added in an amount that achieves a conductivity in the range of 50 μS / cm to 100 μS / cm in the aqueous composition.

4. The method of claim 1, wherein the electrolyte comprises a salt.

5. The method according to claim 1, wherein the electrolyte comprises a halide, sulfate, phosphate, nitrate and / or carbonate.

6. The method according to claim 1, wherein the electrolyte comprises sodium chloride, sodium sulfate, sodium phosphate, or a combination thereof.

7. The method of claim 1, wherein the substrate comprises an organic compound.

8. The method of claim 1, wherein the substrate comprises an inorganic compound.

9. The method of claim 1, wherein water is added in an amount that achieves a concentration of at least 50% by weight in the aqueous composition based on the total weight of the aqueous composition.

10. The method of claim 1, wherein the catalyst is added in an amount such that the concentration of the catalyst in the aqueous composition is in the range of 10 nM to 100 μM.

11. The method of claim 1, wherein the catalyst is added in an amount such that the concentration of the catalyst in the aqueous composition is in the range of 1 μM to 10 μM.

12. The method of claim 1, wherein the catalyst comprises four metal-bonded N-groups, each N-group being selected from the group consisting of amides, sulfonamides, and phosphoramides.

13. The method of claim 12, wherein the catalyst comprises iron, manganese, cobalt, copper, or a combination thereof as the metal.

14. The method of claim 1, wherein the catalyst comprises at least one of the following structures: ; ; ; ; ;and 。 15. The method of claim 1, further comprising adding an additional reagent to the aqueous composition, wherein the additional reagent is selected from the group consisting of wetting agents, surfactants, denaturants, cosolvents, and buffers.

16. The method of claim 1, wherein the aqueous composition does not contain an oxidant prior to the application of the voltage.

17. The method of claim 1, wherein during the oxidation, the pH of the aqueous composition is in the range of 4 to 13.

18. The method of claim 1, wherein during the oxidation, the pH of the aqueous composition is in the range of 6 to 8.

19. The method of claim 1, wherein during the oxidation, the aqueous composition is in a temperature range of 0°C to 95°C.

20. The method of claim 1, wherein the voltage is applied to the aqueous composition to achieve a current density in the aqueous composition greater than 0 to 100 mA / cm². 2 Within the range.

21. The method of claim 1, wherein the voltage is applied to the aqueous composition to achieve a current density in the aqueous composition greater than 0 mA / cm². 2 Up to 500mA / cm 2 Within the range.

22. The method of claim 1, wherein the voltage is applied to the aqueous composition to achieve a current density of 1 mA / cm² in the aqueous composition. 2 Up to 10 mA / cm 2 Within the range.

23. The method of claim 1, further comprising introducing the aqueous composition into an electrolytic cell including an anode and a cathode, wherein the aqueous composition is configured to contact the anode and the cathode, and applying the voltage between the anode and the cathode such that the substrate is oxidized in the presence of the catalyst.

24. A system for the oxidation of a substrate, the system comprising: An electrolytic cell, comprising an anode and a cathode; and A catalyst comprising at least one of the following structures: ; ; ; ; ;and 。

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