Methods of purifying and producing aluminum hydroxide, aluminum formate, aluminum acetate, and porous aluminum carboxylate frameworks fromaluminum(0) for alumina formation

Abstract

Disclosed is a method for producing aluminum hydroxide including a) heating a solution of aluminum hydroxide and organocarboxylic acid, b) filtering the solution to remove insoluble impurities, c) refluxing the filtered solution to form the AOM, d) isolating any produced solid by filtration of supernatant, e) removing unreacted organocarboxylic acid by washing with a solvent, f) removing the solvent from step e) thereby isolating the AOM, g) heating the isolated AOM from step f) whereby aluminum oxide is formed, and h) cooling the aluminum oxide from step g). Also disclosed is a method of producing deuterium gas including reacting a solution of heavy water and aqueous sodium deuteroxide with aluminum, whereby deuterium gas and aluminum deuteroxide are produced.

Description

[0001] METHODS OF PURIFYING AND PRODUCING ALUMINUM HYDROXIDE, ALUMINUM FORMATE, ALUMINUM ACETATE, AND POROUS ALUMINUM CARBOXYLATE FRAMEWORKS FROMALUMINUM(0) FOR ALUMINA FORMATION

[0002] FIELD OF THE DISCLOSURE

[0003] In one of its aspects, the present disclosure relates to the field of aluminum hydroxide, aluminum formate, aluminum acetate, porous aluminum carboxylate frameworks and alumina production.

[0004] BACKGROUND OF THE DISCLOSURE

[0005] Aluminum is one of the most abundant elements present in the earth’s crust, and is heavily used in the automotive, consumer, construction, and electronics industries.1Source aluminum in the earth’s crust exists mainly as aluminum oxides or aluminosilicates in minerals such as bauxite, containing a combination of gibbsite, boehmite and diaspora (A1(OH)3, y-AlO(OH), a-AlO(OH)).2 3Aluminum in this state does not have properties desirable for industrial applications and must be processed to obtain pure aluminum.

[0006] Bauxite is mined and processed through the Bayer process to obtain aluminum hydroxide.4Bauxite is combined in a pressure vessel with a sodium hydroxide solution and heated under pressure up to 200 °C. This converts the aluminum species present (A1(OH)3, y-AlO(OH), a-AlO(OH)) into sodium aluminum hydroxide (Na[Al(OH)4]), an aqueous soluble species.4The insoluble components of bauxite (Fe, Si, Ti species) are filtered off and disposed of. The remaining solution is cooled and seed crystals of aluminum hydroxide and water are added to promote the crystallization of aluminum hydroxide (Al(OH)s). This process is highly energy intensive, requiring heating of large containers filled with bauxite and sodium hydroxide digestion solution to very high temperatures.4The final step of the Bayer process is heating the obtained aluminum hydroxide to temperatures above 1000 °C. This process only produces one desirable product, aluminum oxide, also commonly referred to as alumina.

[0007] The Hall-Heroult process is then used to convert aluminum oxide into pure aluminum. Aluminum oxide is dissolved in molten cryolite (sodium hexafluoroaluminate; NasAlFg) at temperatures above 900 °C, followed by electrolysis to produce pure aluminum metal, also referred to in the present application as aluminum(O).5During the Hall-Heroult process a side product, termed dross, is produced. Dross is a combination of pure aluminum and other aluminum species (oxide, carbide, nitride, phosphide), along with other metal oxides and silicates.6Depending on the aluminum content it is labelled as white or black dross. White dross typically contains between 15% and 80% recoverable aluminum while black dross contains between 7% and 50% recoverable aluminum.7

[0008] During aluminum smelting, it is estimated that dross is produced in 6-8% of the total amount of aluminum produced. Canada produced an estimated 250 000 tonnes of dross in 2022, while the rest of the world produced an estimated 5 300 000 tonnes.8Most of this dross is untreated and put in landfill.9Putting dross in a landfill poses an environmental risk, in which encountering water in an uncontrolled environment can produce toxic gasses including ammonia, phosphine, and methane while other metal components contaminate runoff water.10Given that dross is comprised of valuable materials, it should not be treated as landfill.

[0009] Aluminum reacts with water to produce hydrogen gas and aluminum hydroxide; a major component of the dross is aluminum, making it the ideal material for hydrogen generation.10,11Hydrogen gas is a high-value commodity; it is a carbon-free energy dense gas. As an alternative fuel source, it is extremely attractive; as many governments move towards net zero carbon emissions, hydrogen will replace the burning of other fossil fuels. Previous work examining the hydrogen generation from black dross produced as much as 0.6 liters of hydrogen per gram of dross.10

[0010] Aluminum is an oxyphilic compound, and during dross formation it is oxidized to form an outer layer of aluminum oxide. This outer layer prevents the reaction between water and aluminum and must be removed for efficient generation of hydrogen gas. This is commonly done by ball milling, or by increasing the pH of the water.12,13By reacting the aluminum dross in a solution of sodium hydroxide, hydrogen gas and other value-add materials (including aluminum hydroxide) are produced, while reducing the amount of waste generated through the process.10,14,15

[0011] SUMMARY OF THE DISCLOSURE

[0012] In one aspect, the present disclosure relates to a low-energy, low-waste method for the production of hydrogen gas, aluminum hydroxide, aluminum oxide, and synthetic porous materials directly from aluminum waste. Methods according to aspects of the present disclosure can also be applied to the sustainable formation of deuterium gas from the reaction of aluminum with heavy water (DjO), and sodium deuteroxide (NaOD).

[0013] In another aspect, the present disclosure relates to a closed loop system capable of producing high- value products. Near quantitative high purity hydrogen formation are obtained from white aluminum dross and a sodium hydroxide solution. Sodium hydroxide solution is not consumed in the reaction, and it can be reused near indefinitely without a decrease in the production of hydrogen gas.

[0014] In another aspect, the present disclosure relates to a method to produce aluminum hydroxide as a value-add product from the digestion of aluminum dross and using the aluminum hydroxide to form aluminum formate (ALF), a porous material known for its hydrogen storage capacity. In addition, ALF provides a route to aluminum oxide at a much lower temperature (400 °C) compared to calcination of aluminum hydroxide (600 °C), and is significantly more energy-efficient than the industrially used Bayer process ( 1000+ °C).

[0015] In another aspect, the present disclosure relates to a method for producing aluminum formate including the steps of: a) heating a solution of aluminum hydroxide and formic acid, b) filtering the solution to remove insoluble impurities, c) refluxing the filtered solution to form aluminum formate (ALF), d) removing formic acid from the refluxed solution followed by adding an alcohol to the aluminum formate, e) repeating steps a) through d) with recycled formic acid, f) removing the added alcohol from step d), g) drying the isolated aluminum formate from step f), h) heating the aluminum formate from step g) whereby aluminum oxide is formed, and i) cooling the aluminum oxide from step h). In another aspect, in step h), the aluminum formate is heated to a temperature of below about 1000 °C. In another aspect, in step h), the aluminum formate is heated to a temperature selected from the group consisting of about 350 °C to about 650 °C, about 350 °C to about 700 °C, about 350 °C to about 400 °C, about 400 °C to about 450 °C, about 450 °C to about 500 °C, about 500 °C to about 550 °C, about 550 °C to about 600 °C, about 600 °C to about 650 °C, and about 650 °C to about 700 °C. In another aspect, repeating steps a) through i) (removing step d)) substituting formic acid with acetic acid in forming aluminum hydroxyacetate and subsequent conversion of aluminum hydroxyacetate to aluminum oxide. In another aspect, the aluminum hydroxide in step a) is derived from aluminum dross. In another aspect, the aluminum hydroxide in step a) is derived from recycled aluminum or waste aluminum.

[0016] In another aspect, the present disclosure relates to a method of producing deuterium gas including reacting a solution of heavy water and aqueous sodium deuteroxide with aluminum, whereby deuterium gas and aluminum deuteroxide are produced. In another aspect, the solution is heated for the reaction. In another aspect, the method further includes capturing at least a portion of the deuterium gas. In another aspect, the method further includes recovering at least a portion of the sodium deuteroxide after the reaction, adding additional heavy water and aluminum to the solution and repeating the above reaction. In another aspect, the method further includes reacting a solution of the aluminum deuteroxide with deuterated formic acid, whereby aluminum formate is produced. In another aspect, the solution is refluxed. In another aspect, the method further includes recovering at least a portion of the heavy water and at least a portion of the deuterated formic acid and using the recovered heavy water and the recovered deuterated formic acid to repeat the above method. In another aspect, the present disclosure relates to use of at least a portion of the produced aluminum formate to carry out the above method.

[0017] In another aspect, the present disclosure relates to a method for producing aluminum oxide including a) heating a solution of aluminum hydroxide in acetic acid, b) refluxing the solution, c) precipitating aluminum hydroxyacetate, d) recovering the aluminum hydroxyacetate precipitate from the solution, and e) heating the recovered the aluminum hydroxyacetate above the decomposition temperature of aluminum hydroxyacetate, thereby forming a powder of aluminum oxide. In another aspect, in step e), the aluminum hydroxyacetate is heated to a temperature of about 600 °C. In another aspect, in step e), the aluminum hydroxyacetate is heated to a temperature selected from the group consisting of about 350 °C to about 650 °C, about 350 °C to about 700 °C, about 350 °C to about 400 °C, about 400 °C to about 450 °C, about 450 °C to about 500 °C, about 500 °C to about 550 °C, about 550 °C to about 600 °C, about 600 °C to about 650 °C, and about 650 °C to about 700 °C. In another aspect, the aluminum hydroxide in step a) is derived from aluminum dross. In another aspect, the aluminum hydroxide in step a) is derived from recycled aluminum or waste aluminum. In another aspect, in step a), the solution is heated to boiling. In another aspect, in step a), the solution is heated to about 120 °C.

[0018] In another aspect, the present disclosure relates to a method for producing aluminum oxide including a) heating a solution of aluminum hydroxide and organocarboxylic acid, b) filtering the solution to remove insoluble impurities, c) refluxing the filtered solution to form an organocarboxylate material (AOM), d) isolating any produced solid by filtration of supernatant, e) removing unreacted organocarboxylic acid by washing with a solvent, I) removing the solvent from step e) thereby isolating the AOM, g) heating the isolated AOM from step f) whereby aluminum oxide is formed, and h) cooling the aluminum oxide from step g). In another aspect, the organocarboxylic acid in step a) is liquid organocarboxylic acid. In a further aspect, the organocarboxylic acid in step a) is solid organocarboxylic acid and the solution of step a) further includes a solvent selected from the group consisting of water and an organic solvent. In a still further aspect, the solvent in step e) is selected from the group consisting of an alcohol and a volatile organic solvent. In a still further aspect, the liquid organocarboxylic acid is selected from the group consisting of formic acid, acetic acid, propionic acid, butanoic acid, pentanoic acid, and hexanoic acid. In a still further aspect, the solid organocarboxylic acid is selected from the group consisting of benzoic acid, fumeric acid, maleic acid, succinic acid, terephthalic acid, isophthalic acid, trimesic acid, biphenyl-4,4'-dicarboxylic acid, 3,5-pyrazoledicarboxylic acid monohydrate, l,3,5-Tris(4-carboxyphenyl)benzene, 2,5- dihydroxyterephthalic acid, 2-hydroxyterepthalic acid, 2-aminoterepthalic acid, 2,5- diaminoterepthalic acid, 2-nitroterepthalic acid, 2,5-dinitroterepthalic acid, 2-amino-[l,l’-biphenyl]- 4,4’-dicarboxylic acid, 2,2 ’-diamino- [l,l’-biphenyl] -4, 4’-dicarboxylic acid, 2-nitro- [1,1’ -biphenyl] - 4,4’-dicarboxylic acid 2,2’-dinitro-[l,T-biphenyl]-4,4’-dicarboxylic acid, proline, alanine, glycine, serine, aspartic acid, and glutamic acid. In a still further aspect, the organic solvent is selected from the group consisting of dimethyl formamide, diethyl formamide, dimethyl sulfoxide, N,N-dimethyl- 9-decenamide, or dihydrolevoglucosenone. In a still further aspect, in step g), the AOM is heated to a temperature of below about 1000 °C to form the aluminum oxide. In a still further aspect, in step g), the AOM is heated to a temperature selected from the group consisting of about 350 °C to about 650 °C, about 350 °C to about 700 °C, about 350 °C to about 400 °C, about 400 °C to about 450 °C, about 450 °C to about 500 °C, about 500 °C to about 550 °C, about 550 °C to about 600 °C, about 600 °C to about 650 °C, about 650 °C to about 700 °C, about 700 °C to about 750 °C, about 750 °C to about 800 °C, about 800 °C to 850 °C, about 850 °C to 900 °C, about 900 °C to 950 °C, about 950 °C to 1000 °C. In a still further aspect, the aluminum hydroxide is derived from aluminum dross containing aluminum(O), the recycling of aluminum containing aluminum(O) or waste aluminum containing aluminum(O).

[0019] BRIEF DESCRIPTIONS OF DRAWINGS

[0020] For the purpose of illustrating the invention, the drawings show aspects of one or more embodiments of the invention. However, it should be understood that the present invention is not limited to the precise arrangements and instrumentalities shown in the drawings, wherein:

[0021] Figure 1 is a diffractogram showing a powder X-ray diffraction pattern of a white dross sample after 5 minutes of ball milling;

[0022] Figure 2 is a diffractogram showing a powder X-ray diffraction pattern of aluminum hydroxide precipitated from white dross digestion; Figure 3 is a diagram illustrating a closed loop cycle for the production of hydrogen gas and aluminum hydroxide;

[0023] Figure 4 is infrared (IR) spectra of ALF synthesized from aluminum hydroxide and formic acid;

[0024] Figure 5 is a diffractogram showing a powder X-ray diffraction pattern of ALF made from aluminum hydroxide and formic acid;

[0025] Figure 6 is diffractogram showing a powder x-ray diffraction pattern of ALF after heating to 650 °C;

[0026] Figure 7 is a graph of thermogravimetric analysis of ALF under nitrogen environment;

[0027] Figure 8 are PXRD Diffractograms of ALF (Bottom), ALF heated at 400 °C (Middle) and 650 °C (t°p);

[0028] Figure 9 is a photograph of an exemplary set up for water displacement reactions to measure the amount of hydrogen gas produced from the digestion of dross;

[0029] Figure 10 is a graph of powder x-ray diffraction pattern of ALF as synthesized (bottom graph) and after heating at 600°C (top graph);

[0030] Figure 11 are graphs of powder x-ray diffraction patterns of Al Ac and ALF synthesized via purification methods followed by heating at 400 °C or 600 °C overnight;

[0031] Figure 12 are gas adsorption isotherms of both MOF-303 and AlFum, measured using nitrogen gas at a temperature of 77 K; and

[0032] Figure 13 are powder X-Ray diffraction patterns of MOF-303 (A) and aluminum fumarate (AlFum) (B).

[0033] DETAILED DESCRIPTION

[0034] Dross Characterization

[0035] Dross samples isolated from different locations on a production line were obtained. The aluminum content of the samples was determined through micro-X-ray fluorescence (uXRF). Point source measurements indicated parts of the sample contained up to 98 percent aluminum. The isolated dross is not expected to be a completely homogeneous material; therefore, uXRF maps of the samples were obtained to determine the elemental composition of the samples.16-18The bulk data indicated approximately 75 weight percent aluminum throughout the entire sample, with oxygen being the second most common element varying between 11 and 19 percent.

[0036] To further understand the makeup of the dross samples, powder X-ray diffraction (PXRD) patterns were collected (see Figure 1). The dross samples are made up of aluminum oxide, pure aluminum, magnesium aluminum oxide, iron oxide, and magnesium oxide. The compounds identified in the PXRD diffractograms agree with the elements detected through uXRF.

[0037] Dross Treatment

[0038] As noted above, the outer layer of the dross is oxidized under atmospheric conditions forming an aluminum oxide layer.2Digestion of untreated dross produced a small amount of hydrogen and the reaction stopped after several minutes. The removal of the outer aluminum oxide layer is achieved by placing the dross sample in a ball mill with shaking at rate of 30 Hz for 5 minutes.12,13This leads to both the removal of the aluminum oxide layer and reduction of dross particle size, leading to a larger surface area, promoting faster reaction times.10 12,13

[0039] Hydrogen Generation

[0040] The reaction of aluminum with water is a known reaction that (very slowly) produces hydrogen gas and aluminum hydroxide according to equation l.10,14,19

[0041] The inclusion of sodium hydroxide promotes the formation of sodium aluminates, specifically the soluble sodium aluminum hydroxide. This reaction proceeds as illustrated in equation 2.14

[0042] Sodium aluminum hydroxide is in equilibrium with aluminum hydroxide and sodium hydroxide as shown in equation 3.14

[0043] Na[AZ(OH)]3 Ca<7) o Al(0H)3 {aq}+ NaOH(aq)(3)

[0044] To evaluate the amount of hydrogen produced throughout this reaction, water displacement measurements were performed at room temperature and atmospheric pressure.10,17A I L graduated cylinder was modified (see experimental section below), filled with room temperature water, and inverted in a water bath. The reaction flask was connected to the graduated cylinder with a rubber tube. The reaction was allowed to proceed overnight, ensuring complete digestion of the dross. The results are summarized in Table 1.

[0045] Table 1: Hydrogen production from white dross samples.

[0046] Samples 1-1 to 1-3, 2-1 to 2-3, and 4-1 to 4-3 demonstrated similar hydrogen generation values. On average these samples generated 1.1- 1.2 liters of hydrogen per gram of dross. This is equivalent to 12-13 MJ of energy from one kilogram of dross.

[0047] The aluminum content in each sample was calculated from the volume of generated hydrogen gas. Samples 1-1 to 1-3, 2-1 to 2-3, and 4-1 to 4-3 contained 90 percent or more aluminum, much higher than the average value of 75 percent indicated by uXRF (Table S1-S4). This can be attributed to the uXRF analyzing the surface of the dross. As previously stated, the outer layer of these industrial samples is high in aluminum oxide, causing an increased value of oxygen and a decreased value of aluminum in the sample analysis.13Below the oxide layer is a higher aluminum and lower oxygen content, as the encased dross material is not oxidized with aluminum of higher purity, leading to a higher calculated value of aluminum in the sample.

[0048] The purity of the hydrogen gas was also evaluated. The gas was comprised mainly of hydrogen (92.6%), oxygen (1.5%) and nitrogen (5.9%). The present inventors attribute the presence of oxygen and nitrogen to ambient air in the sample. In atmospheric air, a typical ratio of approximately 4:1 nitrogen to oxygen is present, which was observed (in much lower concentrations) in the gas samples collected. The hydrogen purity was comparable to previously reported values of hydrogen generated from black dross (93.2 mol%).18

[0049] Production of Aluminum Hydroxide

[0050] Hydrogen is the desired, high value product from this reaction. The present inventors have also isolated the value-add product of aluminum hydroxide from this reaction. Aluminum hydroxide is a common reagent used in pharmaceuticals, fire retardants and a common feedstock for aluminum compounds.20 22As mentioned above, the current industrial route to produce aluminum hydroxide is through the Bayer process, which is high in energy and requires the addition of additional reagents.4

[0051] Aluminum hydroxide is soluble in both acidic and basic media, but precipitates in neutral pH. Industrially, neutralizing a high pH system requires large amounts of acid and poses significant safety risks. The present inventors have taken advantage of the solubility properties of aluminum hydroxide and sodium aluminum hydroxide as outlined in equation 2 and the equilibrium shown in equation 3. As aluminum hydroxide saturation occurs, the solid will precipitate, shifting the equilibrium to produce more aluminum hydroxide from sodium aluminum hydroxide in solution, causing more solid to precipitate. Previous patents outline this strategy used; however, they have inaccurately identified the resulting precipitate as aluminum oxide, or broadly as an aluminum oxygen species.23Other work has shown that the reaction of aluminum and sodium hydroxide will produce aluminum hydroxide, however it was not extensively characterized to ensure aluminum hydroxide was produced.15David and Kopac show that the digestion of black dross leads to the formation of aluminum oxide hydroxide, different from the aluminum hydroxide that the present inventors have isolated.10

[0052] The aluminum hydroxide precipitate was characterized through uXRF, revealing aluminum and oxygen (38.5% and 60.1%, respectively) as the major components, with trace amounts of magnesium, sodium, and iron (Table S5). These results agree with the obtained PXRD diffractogram (see Figure 2), displaying major peaks for aluminum hydroxide, and smaller peaks representing magnesium oxide, magnesium aluminum oxide, and aluminum oxide. The magnesium oxide, magnesium aluminum oxide, and aluminum oxide can be attributed to insoluble impurities in the dross or unreacted aluminum. Once aluminum hydroxide begins to precipitate, it encases the remaining dross, preventing the aluminum or aluminum oxide from reacting. Powder X-ray diffraction is primarily sensitive to crystalline materials, and peaks are present for impurities (MgAhO4, MgO, AI2O3; Figure 2), but this does not indicate how much of these materials are present. The uXRF data indicates the bulk of this sample is aluminum hydroxide.

[0053] Recycling Sodium Hydroxide

[0054] Equation 3 illustrates the equilibrium that exists between sodium aluminum hydroxide and sodium hydroxide. As mentioned above, this favours the product generating more aluminum hydroxide and liberating sodium hydroxide, which can further function as a catalyst in propagating the reaction. Once the solid aluminum hydroxide is removed from the reaction, the remaining filtrate contains a similar concentration of sodium hydroxide as the initial solution used for digestion. This filtrate is continuously recycled, creating a near zero waste aspect. Once digestion is complete, a variation of approximately 0. 1 pH units from the starting point can be observed. The variation can be accounted for during the collection of the aluminum hydroxide, water is used to wash it and collected in the filtrate, slightly modifying the pH. The collected sodium hydroxide solution was re-used five times in these experiments, without any noticeable difference in production of hydrogen gas.

[0055] By recycling the sodium hydroxide solution, the present inventors have closed the loop of producing high-value products while minimizing the amount of waste and energy used. This method requires no heating of the digestion solution and no additional reagents compared to the Bayer process. The Bayer process requires mined ore, where the present process uses a waste product, aluminum dross, to generate hydrogen gas and aluminum hydroxide at room temperature, without the use of additional reagents, while recycling the starting sodium hydroxide solution, providing a low-waste and low- energy route to high value products. Figure 3 is a diagram illustrating a closed loop cycle to produce hydrogen gas and aluminum hydroxide.

[0056] Methods according to embodiments of the present invention can be used in addition to the Bayer and Hall-Heroult processes to reduce the amount of waste and to generate high-value products.

[0057] Porous Materials

[0058] Metal-organic frameworks (MOFs) are a class of porous materials that have a robust variety of applications ranging from drug delivery, catalyst, and gas storage.24MOFs are comprised of two main components, an inorganic metal node and organic ligand or linker.24With judicial choice of node and ligand, an extended crystalline network with porosity (akin to zeolitic materials)25is created.

[0059] The isolated aluminum hydroxide is an ideal building block to the MOF aluminum formate (ALF). ALF contains an octahedral aluminum node, joined by formate bridging ligands forming a cubic central pore.26ALF is used for hydrogen storage and carbon dioxide capture, making it a high valueadd material.26,27

[0060] The MOF was successfully synthesized by refluxing the aluminum hydroxide in formic acid overnight. Furthermore, the present inventors synthesized ALF under solvothermal and microwave conditions. Prior art methods for the synthesis of ALF discard the formic acid, creating a waste product.26In the present experiments, the present inventors isolated ALF, and reused the formic acid, to continuously (up to 5 times in one embodiment) produce ALF, making the process even more environmentally friendly.

[0061] The IR spectra (Figure 4), PXRD pattern (Figure 5), and uXRF data (Table S6) of the synthesized ALF matched those previously reported in the literature.26

[0062] The obtained PXRD pattern (see Figure 5) shows all the expected peaks for ALF, with a few minor impurities (Al(OH)j, AI2O3).26As observed in the aluminum hydroxide sample, magnesium aluminum oxide, aluminum oxide, and magnesium oxide are present. This is not surprising as the aluminum hydroxide used during MOF synthesis contained these impurities.

[0063] ALF is a high-value material because of its gas storage and capture potential as previously mentioned. However, ALF can be used as feedstock to produce aluminum oxide. When ALF is heated to 650 °C in the presence of oxygen it decomposes according to equation 4.

[0064] Heating ALF to 650 °C, a loss of the extended crystallinity of the MOF is observed, while the impurities remained in the PXRD diffractogram. After heating, the MOF is converted into amorphous AI2O3. The diffractogram shows a drift in the baseline, indicating the presence of an amorphous material. The present inventors conclude that the amorphous material is aluminum oxide based on the uXRF (Table S7) and the PXRD diffractogram (Figure 6). The uXRF indicated the sample was mainly aluminum, oxygen and magnesium (39.5, 52.5 and 6.3 weight percent respectively). The PXRD diffractogram indicated the presence of aluminum oxide, aluminum, magnesium aluminum oxide, and magnesium oxide in the sample (with magnesium-containing materials comprising of a mere 7% of the total mass). The PXRD shows no peaks corresponding to aluminum hydroxide or ALF, indicating it has been converted to the y-phase of AI2O3 which can also be produced directly from aluminum hydroxide when heated above 550 °C. The peaks that are observed are due to the small amounts of crystalline impurities from the decomposition of the MOF. Interestingly, the TGA profile of ALF (Figure 7) indicates that mass loss (and degradation to Y-AI2O3) is complete below 350 °C. The present inventors can conclude that y-AhOj is formed 200 °C lower than from aluminum hydroxide.

[0065] Though ALF is an important product for its gas storage capabilities, the present inventors can make use of its inherent reactivity during formation to remove impurities from the previously isolated aluminum hydroxide. When ALF is synthesized using pure aluminum hydroxide, heating at 110 °C for 5 minutes results in the aluminum hydroxide dissolution to a clear colourless solution. 5 minutes after the dissolution, ALF precipitates as a white solid. Since the aluminum hydroxide isolated directly from dross digestion contains insoluble impurities (see Figure 2), soluble aluminum hydroxide can be filtered, removing any insoluble metal oxide impurities prior to completion of the ALF reaction. The removal of the impurities was confirmed through the PXRD diffractograms of ALF that was synthesized through this method and heated at 400 °C and 650 °C (see Figure 8).

[0066] The PXRD of ALF matches both the literature and previously collected pattern, however, once heated to both 400 °C and 650 °C a significant difference is observed. In both samples no major peaks are observed, indicating the effective removal of the impurities that were present without the filtering step during synthesis. Furthermore, both samples illustrate a broad peak that spans from approximately 20-35 20 corresponding to the formation of an amorphous material that we attribute to aluminum oxide.22The PXRD patterns also agree with previously published results of heated ALF.26

[0067] Formation of D?

[0068] Current industrial methods for the synthesis of deuterium gas (D2) involve electrolytic separation of heavy water into deuterium gas.28This involves the use of quantities of electricity. Modifying the above prior art hydrogen generation method with heavy water and sodium deuteroxide, D2 gas can be produced quantitively and in high purity, under mild conditions. Sodium hydroxide acts as a catalyst in the reaction scheme of the hydrogen generation method. The present inventors have discovered that sodium deuteroxide (NaOD) can act as a catalyst for the present method of producing deuterium gas. The NaOD is not consumed in the reaction and can be regenerated. The products of the reaction are D2 and Al(OD)a. Furthermore, the A1(OD)3 can be reacted with deuterated formic acid (HCOOD) to give ALF and heavy water. The heavy water can then be separated from the formic acid (HCOOD) and reused to produce more D2.

[0069] Deuterium Generation

[0070] The reaction of aluminum with heavy water produces deuterium gas and aluminum deuteroxide according to equation 5.10,14,19

[0071] The inclusion of sodium deuteroxide promotes the formation of sodium aluminates, specifically the soluble sodium aluminum deuteroxide. This reaction proceeds as illustrated in equation 6.14

[0072] Sodium aluminum deuteroxide is in equilibrium with aluminum deuteroxide and sodium deuteroxide as shown in equation 7.14

[0073] Nfl[AZ(OD)]3(aQ) «-> Al(OD')3(aq} + NaOD(aq}(7)

[0074] The isolated aluminum deuteroxide is an ideal building block to the MOF aluminum formate (ALF). As noted above, ALF is used for hydrogen storage (and deuterium gas storage) and carbon dioxide capture, making it a high value-add material.26,27

[0075] The MOF can be synthesized by refluxing the aluminum deuteroxide in deuterated formic acid (HCOOD) for about 18 hours followed by cooling of the mixture and isolation by vacuum filtration (retentate); see equation 8.

[0076] Examples

[0077] The following are examples of embodiments of various aspects of the present invention.

[0078] Instrumentation

[0079] IR spectra were measured on a Broker Alpha II FT-IR. Thermogravimetric analysis was collected on a labsys evo TGA / DSC (heating at 10 °C / min under N2). Powder X-ray diffraction was collected on a Rigaku Miniflex 600 with a copper radiation source. Micro X-ray fluorescence was collected on a Bruker M4 TomadoPLUS Micro-X-ray fluorescence (pXRF) spectrometer. Ball milling was performed in a Retsch MM400 mixer mill using in house made stainless steel jars with 7mm stainless steel ball bearings.

[0080] Dross Milling and Digestion

[0081] Dross samples were milled for 5 minutes at 30 Hz. The dross was then added to 5M sodium hydroxide, and allowed to react, producing hydrogen gas. Digestion reactions were allowed to run overnight.

[0082] To produce aluminum hydroxide, 25 mL of 5 M sodium hydroxide was added to a 100 mL plastic jar. Dross was added 1 gram at a time until a total of 4-6 grams were added and allowed to react overnight. The solid white / grey / brown precipitate was isolated by suction filtration and washed with a minimal amount of deionized water. The filtrate was collected and further reused in dross digestion experiments.

[0083] Water Displacement Reactions

[0084] To monitor the amount of hydrogen produced, water displacement reactions were performed. In a 50 mL round bottom flask, 25 mL of 5M NaOH and a small amount of milled dross (0.50-0.75 g) was added, and quickly capped with a stopper hooked up to a rubber tube and connected to a graduated cylinder held in a water bath (Figure 9). This reaction was allowed to run overnight at room temperature and atmospheric pressure. The amount of hydrogen produced was calculated at standard temperature and pressure using the room temperature and atmospheric pressure at the time the volume was read.

[0085] ALF Synthesis

[0086] Following established literature procedures, 0.5g of A1(OH)3 isolated from dross was added to 25 mL of formic acid. The solution was refluxed at 110 °C overnight. The solution was removed from heat and allowed to cool to room temperature. Upon cooling the solution was transferred into 2, 15 mL centrifuge tubes and centrifuged for 5 minutes. The formic acid was carefully decanted and re-used for further ALF synthesis. 10 mL of ethanol was added to the tube containing ALF, it was shaken and centrifuged for another 5 minutes, followed by decanting the ethanol. Instead of ethanol, other solvents such as acetone, methanol or isopropyl can be used. This process was repeated 2 additional times. After the ethanol was decanted, ALF was dried in an oven at 80 °C for 2 hours. The sample was then dried under vacuum at 120 °C for about 18 hours or alternatively a sufficient amount of time to sufficiently dry the sample. The sample can also be dried at other temperatures suitable such as 0 °C to 150 °C, 80 °C to 90 °C, 90 °C to 100 °C, 100 °C to 110 °C, 110 °C to 120 °C, 120 °C to 130 °C, 130 °C to 140 °C, and 140 °C to 150 °C.

[0087] In using the ALF synthesis as a method to purify the dross, the procedure was slightly modified. An oil bath was pre-heated to 110 °C and 0.5g of A1(OH)3 was added to a round bottom flask followed by 25 mL of formic acid. This was lowered into the oil bath and a reflux condenser equipped. After 5 minutes of heating, the solution was removed from heat and suction filtered to remove insoluble impurities (retentate). Heating facilitates dissolution of the Al(OH)s, allowing the impurities to be filtered off. The filtrate was then collected and transferred to a round bottom flask and returned to the 110 °C oil bath and refluxed for about 18 hours or alternatively a sufficient amount of time to complete the reaction, by which time ALF precipitates and is isolated by vacuum filtration as the retentate; this same procedure to isolate the ALF as stated above was followed. In other embodiments of the present invention, the Al(OH)s can be heated by other suitable conventional heating means than an oil bath.

[0088] Sample Heating

[0089] The ALF retentate transferred to ceramic crucibles (0.2- 1.5 g) and transferred to a furnace. In one embodiment, the furnace was heated to 400 °C or 650 °C as specified over the course of 6 hours, followed by a 6 hour hold at temperature, and cooled down to room temperature over 6 hours.

[0090] 1. The prior art Bayer process requires temperatures of 1000 °C or greater. According to methods of the present invention, ALF is converted to aluminum oxide at temperatures below the temperatures required for the prior art Bayer process. In other embodiments of the present invention, the furnace can be heated to 350 °C, or in the range of about 350 °C to about 650 °C, or about 350 °C to about 700 °C, or about 350 °C to about 400 °C, or about 400 °C to about 450 °C, or about 450 °C to about 500 °C, or about 500 °C to about 550 °C, or about 550 °C to about 600 °C, or about 600 °C to about 650 °C, or about 650 °C to about 700 °C or to about 750 °C, or about 750 °C to about 800 °C, or about 800 °C to 850 °C, or about 850 °C to 900 °C, or about 900 °C to 950 °C, or about 950 °C to 1000 °C.

[0091] UXRF

[0092] Data below displays elemental compositions of the noted samples by uXRF as required for materials characterizations . Table SI: Elemental composition of dross sample 1

[0093] Table S2: Elemental composition of dross sample 2

[0094] Table S3: Elemental composition of dross sample 3

[0095] Table S4: Elemental composition of dross sample 4

[0096] Table S6: Elemental composition of ALF

[0097] Table S7: Elemental composition of ALF post 650 °C heating

[0098] AlAc

[0099] Aluminum hydroxyacetate (AlAc) was synthesized similarly to previous literature procedures.29Aluminum hydroxide isolated from dross was refluxed in concentrated glacial acetic acid overnight. The resulting precipitate was then isolated by suction filtration and characterized by uXRF, TGA, and PXRD. The obtained PXRD pattern matches the literature for aluminum hydroxyacetate (A1(OH)(CHSCOO)2).. The thermogravimetric analysis of the resulting compound showed a mass loss of 68.8%, within close agreement of the theoretical value of 68.3% and close to the reported value of 68.2%, confirming the formation of A1(OH)(CH3COO)2.29The synthesized AlAc was heated above its decomposition temperature and the resulting powder was characterized through PXRD. After heating at 600 °C overnight the powder pattern no longer matches that of AlAc, and only signals of impurities remain (Figure 10).

[0100] Purification

[0101] Synthesizing ALF and AlAc with impurities are undesirable, as it leads to an impure AI2O3 after heating, discounting their use in the Hall-Heroult process. The present inventors were able to overcome this problem and remove the soluble impurities by dissolution of aluminum hydroxide at the onset of the reaction. The synthesis of these aluminum compounds also removes soluble impurities as the aluminum is the only metal species present that reacts with the reagents to produce a material that can be isolated. In the early stages of the formation of ALF the aluminum hydroxide completely dissolves, while the impurities remain as insoluble solids. The optimal conditions for each synthesis were determined. ALF was synthesized at a loading of 10:1: 1 (A1(OH)3:CHOOH:H2O w:v:w), followed by heating of the mixture for 3 minutes at 110°C. Once the heating phase was complete the insoluble impurities were separated from the filtrate. The filtrate, now containing dissolved aluminum hydroxide and formic acid solution was returned to heating at 110°C. Once the heating was complete a white precipitate remained; this was isolated and identified as ALF via PXRD (Figure 11D). The approach to synthesising pure AlAc was a different than ALF. During the heating of A1(OH)3 in glacial acetic acid the AlAc would precipitate out faster than the A1(OH)3 could be consumed, meaning that filtering the solution to remove the impurities was not possible. To overcome this the impure Al(OH)s isolated was heated in concentrated hydrochloric acid over the course of 2 hours. At this point the Al(OH)s was dissolved, leaving solid impurities to be removed by suction filtration. By adding aqueous sodium hydroxide to achieve a neutral pH of 6-8 a white precipitate, pure A1(OH)3, formed. This pure A1(OH)3 was added to excess glacial acetic acid and heated overnight resulting in a white precipitate, identified as ALF (Figure 11 A).

[0102] The observed PXRD diffractograms observed were the same for both materials regardless of the purification step being performed or not. This is due to the ALF or AlAc being the main component to the sample, and the impurities were not easily detected. To ensure that all impurities were removed the samples were heated at 400°C and 600°C overnight. At these temperatures the ALF or AlAc would convert to the non crystalline y AI2O3 form, and the impurities would still be present as seen previously. After heating ALF that was made via purification at 400°C or 600°C, the resulting PXRD pattern showed no impurities that were previously observed (Figure 11B-C and E-F for AlAc and ALF respectively). The pattern shows no major peaks, but a drift in the baseline, indicating the presence of an amorphous material.29We conclude that the amorphous material is aluminum oxide based on the uXRF and the PXRD diffractogram. The uXRF of the heated ALF indicated the sample was mainly aluminum and oxygen (37.2, 46.4 weight per cent respectively for heating at 400 °C and 32.9 and 49.4 weight per cent respectively for heating at 600°C SI; Tables S8-S9).

[0103] Table S8: ALF purification heating 400

[0104] Element Normalized Weight Percent

[0105] O 37.15

[0106] Na 0.91

[0107] Mg 2.15

[0108] Al 46.4

[0109] Si 0.11

[0110] P 0.07

[0111] Ca 0.08

[0112] Ti 0.03

[0113] V 0.06

[0114] Cr 0.04

[0115] Mn 7.33 Fe 2.69

[0116] Ni 0.07

[0117] Cu 0.57

[0118] Zn 2.34

[0119] Rh 0.00

[0120] Table S9: ALF Purification heating 600

[0121] Element Normalized Weight Percent

[0122] O 32.87

[0123] Na 0.98

[0124] Mg 2.31

[0125] Al 49.4

[0126] Si 0.12

[0127] P 0.07

[0128] Ca 0.04

[0129] Ti 0.04

[0130] V 0.07

[0131] Cr 0.03

[0132] Mn 7.94

[0133] Fe 2.88

[0134] Ni 0.08

[0135] Cu 0.64

[0136] Zn 2.54

[0137] Rh 0.00

[0138] MOF-303 and Aluminum Fumarate

[0139] The isolated aluminum hydroxide is an ideal building block to many aluminum containing MOFs, including ALF, MOF-303, and aluminum fumarate (AlFum). MOF-303 is an aluminum l-H-pyrazole-3,5-dicarboxylate porous material that has gained much attention for its water harvesting capabilities. It was first reported in 2018 by Yaghi and coworkers,29and has been shown to produce up to 1.3 L of water per Kg of MOF per day from the atmosphere at 32% relative humidity.30This material also shows great recyclability demonstrating 97% of the original working capacity after 2000 adsorption and desorption cycles.31MOF-303 shows great potential in providing a source of fresh water to arid and water-depleted regions over the world. In one embodiment of the present invention, this MOF is produced through a waste product, further showing how high value products can come from waste.

[0140] Traditional synthesis to MOF-303 reacts aluminum chloride and sodium hydroxide, generating aluminum hydroxide in situ.32In one embodiment, the method outlined in the present disclosure generates aluminum hydroxide from the reaction of aluminum waste with sodium hydroxide, removing the reliance on aluminum chloride and adding a layer of sustainability to the synthesis. To ensure pure MOF production, in one embodiment, the dross digestion is carried out at a ratio of 1 g of dross per 10 mL of IM sodium hydroxide solution. At this concentration the aluminum hydroxide does not precipitate, and the insoluble impurities are easily separated, resulting in a solution of aluminum hydroxide, ensuring pure MOF-303 is synthesized. The concentration of sodium hydroxide used to digest the aluminum waste in is much higher than the concentration used in the typical synthesis of MOF-303, and synthesis at these concentrations of sodium hydroxide does not successfully synthesize the porous solid. Using this method, MOF-303 was successfully assembled from dross by diluting the aluminum hydroxide solution with water at a ratio of approximately 1:11.5 to obtain a similar aluminum and sodium hydroxide concentration to the established protocols. The Combining the above aluminum hydroxide solution with the ligand in a vial, followed by heating overnight yielded a white powder. Once washed with water and alcohol (methanol or ethanol) pure MOF-303 was obtained.32

[0141] AlFum combines an aluminum centre with a fumaric acid ligand; it is an industrially relevant MOF produced at scale by BASF (BASF A 520).33AlFum has shown potential for CO2 adsorption from wet gas streams, photocatalytic hydrogen production, and chlorofluorocarbons adsorption and selectivity.33-35The synthesis that BASF preforms on the tonne scale uses aluminum sulphate and sodium hydroxide to generate aluminum hydroxide in situ.33Using the same procedure as highlighted for MOF-303, a solution of aluminum hydroxide was produced that was diluted with water at a ratio of 1:20 to synthesize AlFum from waste aluminum, adding a layer of sustainability to this industrial synthesis.

[0142] The synthesis of both MOFs was confirmed via N2 adsorption measurements. Both MOF- 303 and AlFum produced a type I isotherm, and a calculated BET surface area of 1450 and 850 m2 / g, respectively (Figure 12).32’35Both calculated values agree with previously published literature.32Furthermore, the PXRD pattern of our synthesized material match those published in the literature (Figure 13).32’35

[0143] Examples

[0144] AlAc Synthesis

[0145] In a 50 mL round bottom flask with a stir bar, 0.10 g of A1(OH)3 from dross was suspended in 20 mL of glacial acetic acid (GAA) and 10 mL water. GAA is more sustainable and less expensive than formic acid. The mixture was fitted with a waterless reflux condenser and heated to 120°C. After 5 minutes, all the Al(OH)a was dissolved, creating a clear and colourless solution. The following day, the solution was removed from heat and allowed to cool to room temperature. The resulting turbid white suspension was centrifuged for 5 minutes, and the mother liquor decanted. The remaining white powder was washed and spun with water and ethanol (3x5 mL each). Finally, the product was left to dry at 90°C in an oven until a friable powder remained.

[0146] Purification by AlAc Synthesis

[0147] In a 100 mL round bottom flask equipped with a stir bar, 5.00 g of crude A1(OH)3 from dross was suspended in 50 mL concentrated HC1. A waterless condenser was attached, and the mixture was heated at 120°C overnight with strong stirring. The following day, the mixture was cooled to room temperature, vacuum filtered, and the pH of the filtrate was adjusted to 7 using 5M NaOH. The resulting precipitate was collected via vacuum filtration and cleaned by sonicating in water (3x100 mL). Next, 2.00 g of this Al(OH)s was added to a 100 mL round bottom flask followed by 20 mL of GAA and a waterless condenser. The mixture was heated to 120°C overnight and the following morning, AlAc was collected after centrifugation and washing with water and ethanol (3x5 mLeach). The white solid was left to dry in a 90°C oven until a friable powder remained.

[0148] Aqueous Al Standard Solution

[0149] An aqueous solution of aluminum was first prepared by milling white dross for 5 minutes at 30 Hz. The powder was then weighed (3.72 g). Next, a solution of NaOH (IM or 5M) was weighed out to comply with a loading of 10 g of NaOH(aq) solution to 1 g of dross (37.20 g). The NaOH was then added to a Nalgene bottle with a stir bar and the mass of the entire vessel was recorded. The vessel was placed on a stir plate and milled dross was slowly added, ensuring the container did not spill over. The mixture was left to stir and digest overnight before being weighed in the morning. Any reduction in mass due to water loss was replenished with water to restore the original concentration of the solution. Finally, impurities were removed via gravity filtration and the resulting solution of aqueous aluminum was collected.

[0150] MOF-303 from Aqueous Solution

[0151] To an 8-dram vial charged with 0.258 g (1.48 mmol, 1 eq.) PZDC monohydrate, 0.4 mL (1.48 mmol, 1 eq. by Al) of aqueous aluminum solution (IM NaOH) was added along with 4.6 mL of water. The reaction vessel was sonicated for 5 minutes before the pH of the solution was verified (pH = 4.65). The vessel was then placed in an oven set to 100°C and left overnight. The following day, the contents were removed from the oven and allowed to cool to room temperature before being centrifuged and the mother liquor decanted. The resulting solid was washed thoroughly with water and methanol (3x5 mL each) before being placed in a round bottom flask with a stir bar. To the round bottom flask, 7 mL of water was added followed by a waterless condenser. The suspension was brought to reflux for 1 hours before being cooled to room temperature, then centrifuged to remove the water. The remaining powder was allowed to dry in a 90°C oven until a loose powder sat at the bottom of the tube. See PXRD (Fig 12a) and Gas sorption data (Fig 13a).

[0152] AlFum From Aqueous Solution

[0153] In a 50 mL round bottom flask equipped with a stir bar, 1.0 mL of aqueous aluminum digest solution (IM, NaOH, 0.0037 mol, 1 eq. by Al), 537 mg fumaric acid (0.0046 mol, 1.25 eq.) and 20 mL DMF were combined and stirred. This mixture was heated to a gentle reflux at 120 °C for 96 hours. The resulting white powder was collected in a centrifuge tube and washed thoroughly with DMF, water and EtOH subsequentially. Hie synthesized AlFum was dried at 90 °C prior to activation and analysis. See PXRD (Fig 12b) and Gas sorption data (Fig 13b).

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Claims

CLAIMS1. A method for producing aluminum oxide comprising: a) heating a solution of aluminum hydroxide and organocarboxylic acid, b) filtering the solution to remove insoluble impurities, c) refluxing the filtered solution to form an organocarboxylate material (AOM), d) isolating any produced solid by filtration of supernatant in the solution, e) removing unreacted organocarboxylic acid by washing with a solvent, f) removing the solvent from step e) thereby isolating the AOM, g) heating the isolated AOM from step f) whereby aluminum oxide is formed, and h) cooling the aluminum oxide from step g).

2. The method of claim 1, wherein the organocarboxylic acid in step a) is liquid organocarboxylic acid.

3. The method of claim 1, wherein the organocarboxylic acid in step a) is solid organocarboxylic acid and the solution of step a) further comprises a solvent selected from the group consisting of water and an organic solvent.

4. The method of any one of claims 1 to 3, wherein the solvent in step e) is selected from the group consisting of an alcohol and a volatile organic solvent.

5. The method of claim 2, wherein the liquid organocarboxylic acid is selected from the group consisting of formic acid, acetic acid, propionic acid, butanoic acid, pentanoic acid, and hexanoic acid.

6. The method of claim 3, wherein the solid organocarboxylic acid is selected from the group consisting of benzoic acid, fumeric acid, maleic acid, succinic acid, terephthalic acid, isophthalic acid, trimesic acid, biphenyl-4,4'-dicarboxylic acid, 3,5-pyrazoledicarboxylic acid monohydrate, l,3,5-Tris(4-carboxyphenyl)benzene, 2,5-dihydroxyterephthalic acid, 2- hydroxyterepthalic acid, 2-aminoterepthalic acid, 2,5-diaminoterepthalic acid, 2- nitroterepthalic acid, 2,5-dinitroterepthalic acid, 2-amino-[l,l’-biphenyl]-4,4’-dicarboxylic acid, 2,2’-diamino-[l,r-biphenyl]-4,4’-dicarboxylic acid, 2-nitro-[l,l’-biphenyl]-4,4’- dicarboxylic acid 2, 2’-dinitro-[l,l’-biphenyl]-4, 4’ -dicarboxylic acid, proline, alanine, glycine, serine, aspartic acid, and glutamic acid.

7. The method of claim 3, wherein the organic solvent is selected from the group consisting of dimethyl formamide, diethyl formamide, dimethyl sulfoxide, A7,A-dimcthyl-9-dccenamide, or dihydrolevoglucosenone.

8. The method of any one of claims 1 to 7, wherein in step g), the AOM is heated to a temperature of below about 1000 °C to form the aluminum oxide.

9. The method of any one of claims 1 to 7, wherein in step g), the AOM is heated to a temperature selected from the group consisting of about 350 °C to about 650 °C, about 350 °C to about 700 °C, about 350 °C to about 400 °C, about 400 °C to about 450 °C, about 450 °C to about 500 °C, about 500 °C to about 550 °C, about 550 °C to about 600 °C, about 600 °C to about 650 °C, about 650 °C to about 700 °C, about 700 °C to about 750 °C, about 750 °C to about 800 °C, about 800 °C to 850 °C, about 850 °C to 900 °C, about 900 °C to 950 °C, about 950 °C to 1000 °C.

10. The method of any one of claims 1 to 9, wherein the aluminum hydroxide is derived from aluminum dross containing aluminum(O).

11. The method of any one of claims 1 to 9, wherein the aluminum hydroxide is derived from recycling aluminum containing aluminum(O).

12. The method of any one of claims 1 to 9, wherein the aluminum hydroxide is derived from waste aluminum containing aluminum(O).

13. The method of any one of steps 1 to 12, further comprising the step of repeating steps a) to d) using the unreacted organocarboxylic acid removed in step e).

14. The method of any one of claims 1 to 13, further including the step of drying the isolated AOM from step f).

15. A method of producing deuterium gas comprising: reacting a solution of heavy water and aqueous sodium deuteroxide with aluminum, whereby deuterium gas and aluminum deuteroxide are produced.

16. The method of claim 15, wherein the solution is heated for the reaction.

17. The method of claim 15, further comprising capturing at least a portion of the deuterium gas.

18. The method of claim 15, further comprising: recovering at least a portion of the sodium deuteroxide after the reaction, adding additional heavy water and aluminum to the solution and repeating the reaction of claim 15.

19. The method of claim 15, further comprising: reacting a solution of the aluminum deuteroxide with deuterated formic acid, whereby aluminum formate is produced.

20. The method of claim 16, wherein the solution is refluxed.

21. The method of claim 16, further comprising: recovering at least a portion of the heavy water and at least a portion of the deuterated formic acid and using the recovered heavy water and the recovered deuterated formic acid to repeat the method of claim 15.

22. Use of at least a portion of the produced aluminum formate of claim 16 to carry out the method of claims 8 and 9.

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