Three-layer coated hydrogen-absorbing oxygen and water blocking microcapsules, and preparation method and application thereof

Abstract

The present application relates to the technical field of hydrogen absorption, in particular to a three-layer coated hydrogen absorption oxygen and water blocking microcapsule, a preparation method and application thereof, wherein hydrogen absorption powder is pressed into tablets and then coated with three layers, and the coating solution used in the coating contains hydroxypropyl methyl cellulose, polystyrene and / or reduced graphene oxide. By adding PS and rGO as coating materials and selecting a suitable thickness for coating, the hydrogen absorption microcapsule has the characteristics of hydrogen absorption, oxygen blocking and water blocking.

Description

Technical Field

[0001] This invention relates to the field of hydrogen absorption technology, specifically to a three-layer coated hydrogen-absorbing, oxygen-barrier, and water-barrier microcapsule, its preparation method, and its application. Background Technology

[0002] Hydrogen is a widely available gaseous component. Its small atomic radius allows it to easily penetrate the interior of materials, potentially leading to hydrogen-induced cracking. Furthermore, hydrogen accumulation in confined environments poses an explosion risk, threatening environmental safety. Therefore, effective control of hydrogen in confined environments is necessary to improve environmental reliability.

[0003] 1,4-Bis(phenylethynyl)benzene is a commonly used irreversible hydrogen-absorbing material that can efficiently adsorb hydrogen from the environment under palladium on carbon catalysis. However, according to relevant studies, in a mixed atmosphere of hydrogen and oxygen, most of the oxygen in 1,4-bis(phenylethynyl)benzene reacts on the surface of the palladium on carbon to form water, leading to an increase in the water vapor concentration in the environment and accelerating the corrosion of internal components in sealed circuits. Therefore, it is necessary to coat the hydrogen-absorbing material with a hydrogen-permeable, oxygen-barrier, and water-barrier film to ensure the hydrogen absorption performance of the material while preventing oxygen from entering the material and reacting with hydrogen to form water, thus reducing the impact of water in the environment on the hydrogen-absorbing material and the water vapor produced by the material on the environment.

[0004] Currently, there are no patents or journal articles on achieving the oxygen-blocking, water-blocking, and hydrogen-permeable effects of hydrogen-absorbing materials through coating methods. Summary of the Invention

[0005] The purpose of this invention is to provide a three-layer coated hydrogen-absorbing, oxygen-blocking, and water-blocking microcapsule, its preparation method, and its application, thereby solving the technical problem that there is currently no method in the prior art to achieve the oxygen-blocking and hydrogen-permeable effects of hydrogen-absorbing materials through coating.

[0006] This invention discloses a method for preparing three-layer coated hydrogen-absorbing, oxygen-barrier, and water-barrier microcapsules, comprising the following steps:

[0007] The hydrogen-absorbing powder is compressed into tablets and then coated with a three-layer coating solution containing hydroxypropyl methylcellulose, polystyrene (PS), and / or reduced graphene oxide (rGO).

[0008] Furthermore, the coating layers are arranged in the order of being furthest from the hydrogen-absorbing powder: first coating layer, second coating layer, and third coating layer.

[0009] Furthermore, the thickness of the first coating layer is 0.5μm to 2μm, the thickness of the second coating layer is 15μm to 35μm, and the thickness of the third coating layer is 5μm to 15μm.

[0010] Furthermore, the coating solution for the first coating layer is a hydroxypropyl methylcellulose solution, hydroxypropyl cellulose, or ethyl cellulose.

[0011] Furthermore, the solvent of the coating solution for the first coating layer is anhydrous ethanol and dichloromethane.

[0012] Furthermore, the ratio of solvent to anhydrous ethanol in the coating solution of the first coating layer is 1g:(20-30)mL, and the volume ratio of dichloromethane to anhydrous ethanol is 1.2-1.5:1.

[0013] Furthermore, the coating solution for the second coating layer is a polystyrene (PS) solution.

[0014] Furthermore, the solvent for the polystyrene (PS) solution is dichloromethane.

[0015] Furthermore, the ratio of polystyrene to dichloromethane in the polystyrene (PS) solution is 1 g : (100-150) mL.

[0016] Furthermore, the coating solution for the third coating layer is a mixed solution of reduced graphene oxide (rGO) and polystyrene (PS), and the solvent is dichloromethane.

[0017] Furthermore, in the mixed solution of reduced graphene oxide (rGO) and polystyrene (PS), the ratio of polystyrene to dichloromethane is 1g:(100-150)mL, and the ratio of polystyrene to reduced graphene oxide is 100g:(1-5)g; the number of reduced graphene oxide layers is ≤3.

[0018] Furthermore, after the first layer of coating is completed, the next layer of coating is applied.

[0019] Furthermore, the weight ratio of the hydrogen-absorbing powder to the polystyrene in the three-layer coating solution is 500g:(3-10)g, the coating speed is 3-10rpm, the coating temperature is 28-32℃, the material is dried after coating, the material temperature is controlled at 40-45℃, and the drying time is 20-30min.

[0020] Furthermore, the hydrogen-absorbing powder tableting step involves granulating and sizing the hydrogen-absorbing powder before tableting.

[0021] Furthermore, the granulation process involves first dissolving the hydrogen-absorbing powder in a granulation solvent, and then adding a binder to granulate the mixture to obtain a soft material.

[0022] Furthermore, the granulation process involves drying and granulating the soft material, then adding magnesium stearate to the granulated soft material and mixing it.

[0023] Furthermore, the hydrogen-absorbing powder is DEB-Pd / C powder, and the granulation solvent is ethanol.

[0024] Furthermore, the ratio of the hydrogen-absorbing powder to the granulation solvent is 500g:(100-150)mL.

[0025] Furthermore, the ratio of the granulation solvent to the binder is 100ml:(10-30)g.

[0026] Furthermore, the adhesive is at least one of hydroxypropyl methylcellulose, carboxymethyl cellulose, or hydroxyethyl cellulose.

[0027] Furthermore, the ratio of the hydrogen-absorbing powder to magnesium stearate is 100g:(1-3)g.

[0028] A three-layer coated hydrogen-absorbing, oxygen-barrier, and water-barrier microcapsule was prepared using the method described above.

[0029] An application of a three-layer coated hydrogen-absorbing, oxygen-barrier, and water-barrier microcapsule for hydrogen absorption in a closed environment.

[0030] Furthermore, it can be used to absorb hydrogen in oxygen-containing spaces.

[0031] Furthermore, it can be used for hydrogen absorption in water-containing spaces.

[0032] Compared with the prior art, the beneficial effects of the present invention are:

[0033] 1. Add PS as a coating material and select an appropriate thickness for coating so that the hydrogen-absorbing microcapsules have both hydrogen absorption and oxygen barrier properties;

[0034] 2. PS and reduced graphene oxide are used as composite layers to further enhance the oxygen barrier effect while ensuring the material's original excellent hydrogen absorption performance.

[0035] 3. The hydrogen-absorbing microcapsules with two layers of coating have higher integrity and mechanical strength, and possess hydrogen permeability and oxygen barrier properties, meaning that the coating layer can effectively prevent oxygen from entering the particles.

[0036] 4. The three-layer coated hydrogen-absorbing microcapsules retain high hydrogen absorption performance, further enhance oxygen barrier performance, and also have water-blocking properties. Attached Figure Description

[0037] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0038] Figure 1 This invention relates to PS / rGO1 hydrogen-absorbing, oxygen-blocking, and water-blocking microcapsules.

[0039] Figure 2 This is a surface SEM image of the PS / rGO1 hydrogen-absorbing, oxygen-blocking, and water-blocking microcapsules of the present invention.

[0040] Figure 3 This is a cross-sectional SEM image of the PS / rGO1 hydrogen-absorbing, oxygen-blocking, and water-blocking microcapsules of the present invention.

[0041] Figure 4 This is a diagram showing the state of the PS / rGO1 microcapsules after thermal environment testing.

[0042] Figure 5 This is a surface SEM image of the PS / rGO1 hydrogen-permeable, oxygen-barrier, and water-barrier microcapsules of the present invention after a 28-day thermal environment test at 55°C.

[0043] Figure 6 This is a cross-sectional SEM image of the PS / rGO1 hydrogen-permeable, oxygen-barrier, and water-barrier microcapsules of the present invention after a 28-day thermal environment test at 55°C.

[0044] Figure 7 The present invention relates to PS / rGO2 microcapsules.

[0045] Figure 8 This is a surface SEM test result of the water-blocking PS / rGO2 microcapsules of the present invention.

[0046] Figure 9 This is a cross-sectional SEM image of the PS / rGO2 microcapsules of the present invention.

[0047] Figure 10 The image shows the Raman test results of the HPMC1, PS1, and PS / rGO1 microcapsules of this invention. Detailed Implementation

[0048] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments.

[0049] Example 1

[0050] This embodiment discloses a method for preparing a three-layer coated hydrogen-absorbing, oxygen-barrier, and water-barrier microcapsule, comprising the following steps:

[0051] 1) Preparation of hydroxypropyl methylcellulose binder: Add 15g of cellulose to 100mL of ethanol;

[0052] 2) Granulation: First, add 500g of DEB-Pd / C powder to a wet granulator, then slowly add 100mL of the prepared hydroxypropyl methylcellulose binder for granulation. Next, dry the soft material at 60℃ for 3 hours.

[0053] 3) Granulation: Finally, granulation is carried out by adding 5g of magnesium stearate to the granulated soft material and mixing.

[0054] 4) Tableting: The granulated material is tableted using a tablet press. A 2.5mm shallow concave die tableting mold is installed, the tableting speed is 5rpm, and the tableting pressure is 6kg.

[0055] 5) Prepare the coating solution: Add 10g of hydroxypropyl methylcellulose to 200mL of anhydrous ethanol for dispersion, then add 240mL of dichloromethane and stir to dissolve to obtain the coating solution.

[0056] 6) Coating: Add the tableted material and coating solution to the coating machine, control the rotation speed to 5 rpm, the coating temperature to 30℃, and the coating time to 3 hours. After coating, dry for 30 minutes at 40℃.

[0057] 7) Preparation of the second coating solution: Add 10g of polystyrene (PS) to 1200mL of dichloromethane and stir until dissolved;

[0058] 8) Second-layer coating: Add the hydrogen-absorbing material and the prepared second-layer coating solution to the coating machine; the coating time is 2 hours, the coating speed is 7 rpm, and the coating temperature is 30℃. No sticking or other phenomena occur during the coating process. After the second-layer coating is completed, dry the material at 42℃ for 20 minutes to obtain hydrogen-absorbing and oxygen-barrier microcapsules.

[0059] 8) Preparation of three-layer coating solution: Add 5g of polystyrene (PS) to 600mL of dichloromethane, stir until dissolved, and then add 50mg of reduced graphene oxide (rGO);

[0060] 9) Three-layer coating: The hydrogen-absorbing material and the three-layer coating solution are added to the coating machine. The coating time is 2 hours, the coating speed is 5 rpm, and the coating temperature is 28℃. No sticking or other phenomena occur during the coating process. After the three-layer coating is completed, the material is dried at 45℃ for 30 minutes to obtain PS / rGO1 hydrogen-absorbing, oxygen-barrier, and water-barrier microcapsules. Figure 1-3 As shown.

[0061] The hydrogen absorption performance of PS / rGO1 hydrogen-absorbing, oxygen-barrier, and water-barrier microcapsules was tested, and its hydrogen absorption capacity reached 200.6 mL / g.

[0062] The PS / rGO1 hydrogen-absorbing, oxygen-barrier, and water-barrier microcapsules were placed in a sealed environment with a hydrogen-oxygen mixture at a hydrogen concentration of 2.0% ± 1.0% and an oxygen concentration of 10%–30% for 7 days. The decrease in hydrogen and oxygen levels in the environment before and after the test is shown in Table 1. According to the test results, after 7 days, the oxygen content in the environment only decreased slightly, and the hydrogen was almost completely absorbed, which proves the material's good oxygen-barrier and hydrogen-absorbing properties.

[0063] Table 1. Changes in hydrogen and oxygen levels after PS / rGO1 was placed in a hydrogen-oxygen mixture for 7 days.

[0064]

[0065] Figure 10 The Raman spectroscopy results for HPMC1, PS1, and PS / rGO1 microcapsules clearly show the G and D peaks of the PS / rGO1 microcapsule, proving the successful doping of reduced graphene oxide onto the PS / rGO microcapsule.

[0066] The PS / rGO1 hydrogen-absorbing, oxygen-barrier, and water-blocking microcapsules prepared by this method maintained an intact coating layer after a 28-day thermal environment test at 55℃. Figures 4-6 As shown in Table 2, the compression strength before and after the test indicates that the microcapsules have strong environmental adaptability and are suitable for various hydrogen absorption scenarios.

[0067] Table 2. Compression strength of PS / rGO1 hydrogen-absorbing, oxygen-barrier, and water-barrier microcapsules before and after environmental testing.

[0068] Environmental testing After thermal environment test 4.45 MPa 4.28 MPa (96.18%)

[0069] Comparative Example 1

[0070] This embodiment, as a comparative example of the present invention, discloses a method for preparing a three-layer coated hydrogen-absorbing, oxygen-barrier, and water-blocking microcapsule, comprising the following steps:

[0071] 1) Preparation of hydroxypropyl methylcellulose binder: Add 15g of cellulose to 100mL of ethanol;

[0072] 2) Granulation: First, add 500g of DEB-Pd / C powder to a wet granulator, then slowly add 100mL of the prepared hydroxypropyl methylcellulose binder for granulation. Next, dry the soft material at 60℃ for 3 hours.

[0073] 3) Granulation: Finally, granulation is carried out by adding 5g of magnesium stearate to the granulated soft material and mixing.

[0074] 4) Tableting: The granulated material is tableted using a tablet press. A 2.5mm shallow concave die tableting mold is installed, the tableting speed is 5rpm, and the tableting pressure is 6kg.

[0075] 5) Prepare the coating solution: Add 10g of hydroxypropyl methylcellulose to 200mL of anhydrous ethanol for dispersion, then add 240mL of dichloromethane and stir to dissolve to obtain the coating solution.

[0076] 6) Coating: Add 500g of the compressed material and coating solution to the coating machine, control the rotation speed at 5rpm, the coating temperature at 30℃, and the coating time at 3h. After coating, dry for 30min at 40℃.

[0077] 7) Preparation of the second coating solution: Add 10g of polystyrene (PS) to 1500mL of dichloromethane and stir until dissolved;

[0078] 8) Secondary Coating: Add 500g of hydrogen-absorbing material and the prepared secondary coating solution to the coating machine; the coating time is 2 hours, the coating speed is 7 rpm, and the coating temperature is 30℃. No sticking or other phenomena occur during the coating process. After the secondary coating is completed, dry the material at 42℃ for 20 minutes to obtain hydrogen-absorbing, oxygen-barrier, and water-barrier microcapsules.

[0079] 8) Preparation of three-layer coating solution: Add 8g of polystyrene (PS) to 600mL of dichloromethane, stir until dissolved, and then add 500mg of reduced graphene oxide (rGO);

[0080] 9) Three-layer coating: Add 500g of hydrogen-absorbing material and the three-layer coating solution to the coating machine. The coating time is 2 hours, the coating speed is 8 rpm, and the coating temperature is 28℃. No sticking or other phenomena occur during the coating process. After the three-layer coating is completed, dry the material at 45℃ for 30 minutes to obtain PS / rGO2 microcapsules. Figures 7-9 As shown.

[0081] PS / rGO2 microcapsules were placed in a sealed environment with a hydrogen concentration of 2.0% ± 1.0% and an oxygen concentration of 10%–30% in a nitrogen, hydrogen, and oxygen mixed atmosphere for 7 days. The decrease in hydrogen and oxygen in the environment before and after the test was measured, as shown in Table 3. According to the experimental results, after 7 days, the oxygen concentration decreased and the hydrogen was not completely absorbed. Compared with PS / rGO1 microcapsules, the hydrogen permeability and oxygen barrier effect decreased after adding more rGO.

[0082] Table 3. Changes in hydrogen and oxygen levels after PS / rGO2 is placed in a hydrogen-oxygen mixture for 7 days.

[0083]

[0084] Comparative Example 2

[0085] This embodiment discloses a method for preparing double-layer coated hydrogen-absorbing and oxygen-barrier microcapsules, including the following steps:

[0086] 1) Preparation of hydroxypropyl methylcellulose binder: Add 15g of cellulose to 100mL of ethanol;

[0087] 2) Granulation: First, add 500g of DEB-Pd / C powder to a wet granulator, then slowly add 100mL of the prepared hydroxypropyl methylcellulose binder for granulation. Next, dry the soft material at 60℃ for 3 hours.

[0088] 3) Granulation: Finally, granulation is carried out by adding 5g of magnesium stearate to the granulated soft material and mixing.

[0089] 4) Tableting: The granulated material is tableted using a tablet press. A 2.5mm shallow concave die tableting mold is installed, the tableting speed is 5rpm, and the tableting pressure is 6kg.

[0090] 5) Prepare the coating solution: Add 10g of hydroxypropyl methylcellulose to 200mL of anhydrous ethanol for dispersion, then add 240mL of dichloromethane and stir to dissolve to obtain the coating solution.

[0091] 6) Coating: The tableted material and coating solution are added to the coating machine, the rotation speed is controlled at 5 rpm, the coating temperature is 30℃, the coating time is 3h, and after coating is completed, the material is dried for 30min at 40℃ to obtain HPMC1.

[0092] 7) Preparation of the second coating solution: Add 10g of polystyrene (PS) to 1500mL of dichloromethane and stir until dissolved;

[0093] 8) Secondary Coating: Add the hydrogen-absorbing material and the prepared secondary coating solution to the coating machine; the coating time is 3 hours, the coating speed is 5 rpm, and the coating temperature is 30℃. No sticking or other phenomena occur during the coating process. After the secondary coating is completed, dry the material at 40℃ for 30 minutes to obtain the hydrogen-absorbing and oxygen-barrier microcapsules PS1.

[0094] test

[0095] 1. Mechanical strength

[0096] Table 4 shows the comparison of compressive strength of different samples. Uncoated tablets have a certain compressive strength, but the compressive strength is low. After HPMC coating, the compressive strength of the particles is significantly improved. After further coating, the compressive strength is further improved due to the strength-enhancing properties of rGO composite polymer materials.

[0097] Table 4. Comparison of compressive strength of different samples

[0098] Sample Name Compressive strength (MPa) Uncoated tablets 1.89 HPMC1 4.09 PS1 4.11 PS / rGO1 4.45

[0099] 2. Integrity of coating / water-blocking properties

[0100] During the granulation process of the hydrogen-absorbing material, NaCl was added to the hydroxypropyl methylcellulose binder solution at a weight ratio of 1g:30g, and the mixture was thoroughly mixed. Five hydrogen-absorbing particles were placed in deionized water, and the Na+ content in the water was tested by ICP-OES after 24h and 48h, respectively, to evaluate the coating integrity and water-blocking properties.

[0101] NaCl was mixed in during the processing of hydrogen-absorbing materials. The hydrogen-absorbing particles were then soaked in water, and the solubility of Na+ in the water was tested. According to the test results, only the HPMC-coated hydrogen-absorbing particles had a thinner coating layer. During soaking, water gradually entered the interior of the hydrogen-absorbing particles, causing Na+ to dissolve in the water. PS3, due to its thin and uneven coating layer, showed higher Na+ solubility. + The content is low, and the water-blocking ability of the particles is poor; the coating layer of PS1 particles is of appropriate thickness and the coating is complete, which has a certain water-blocking effect; after the third coating layer of Ps / rGO1, the water-blocking characteristics of the particles are significantly improved due to the water-blocking effect of rGO itself, as shown in Table 5.

[0102] Table 5. Water-blocking properties of particles

[0103] sample <![CDATA[Na + 24-hour content (mg / L) <![CDATA[Na + 48h content (mg / L) HPMC1 24.11 27.49 PS1 7.30 7.34 PS / rGO1 0.10 1.03

[0104] 3. Hydrogen absorption performance

[0105] Table 6. Comparison of Saturated Hydrogen Absorption Capacity

[0106] Sample Name Saturated hydrogen absorption capacity (mL / g) HPMC1 210 PS1 206 PS / rGO1 200.6

[0107] As shown in Table 6, since HPC, PS, and rGO materials themselves do not have hydrogen absorption properties, HPMC1, with only one layer of coating, has the highest hydrogen absorption capacity. The saturated hydrogen absorption capacity of coated PS1 reaches 206 mL / g. After coating with three layers of PS / rGO, the saturated hydrogen absorption capacity further decreases, but the decrease is small and still reaches 200.6 mL / g. This indicates that PS / rGO1 maintains good hydrogen absorption performance while having both oxygen and water barrier properties.

[0108] 4. Hydrogen permeability and oxygen barrier properties

[0109] As shown in Table 7, compared with HPMC, the H2 / O2 consumption ratio of the hydrogen-absorbing microcapsules was significantly increased after further coating treatment, indicating that the particles have oxygen barrier properties and can effectively reduce the proportion of oxygen entering the hydrogen-absorbing microcapsules and reacting with H2.

[0110] Table 7. Comparison of hydrogen permeability and oxygen barrier properties of different samples

[0111]

[0112] The above are the embodiments listed in this example. However, this example is not limited to the optional embodiments described above. Those skilled in the art can arbitrarily combine the above methods to obtain other various embodiments. Anyone can derive other various forms of embodiments based on the inspiration of this example. The above specific embodiments should not be construed as limiting the scope of protection of this example. The scope of protection of this example should be determined by the claims, and the specification can be used to interpret the claims.

Claims

1. A method for preparing a three-layer coated hydrogen-absorbing, oxygen-barrier, and water-barrier microcapsule, characterized in that: The hydrogen-absorbing powder is compressed into tablets and then coated with a three-layer coating solution containing hydroxypropyl methylcellulose, polystyrene, and / or reduced graphene oxide.

2. The method for preparing a three-layer coated hydrogen-absorbing, oxygen-barrier, and water-barrier microcapsule according to claim 1, characterized in that: The coating layers are arranged in the order of being furthest from the hydrogen-absorbing powder: first coating, second coating, and third coating.

3. The method for preparing a three-layer coated hydrogen-absorbing, oxygen-barrier, and water-barrier microcapsule according to claim 2, characterized in that: The coating solution for the first coating layer is a hydroxypropyl methylcellulose solution, hydroxypropyl cellulose, or ethyl cellulose.

4. The method for preparing a three-layer coated hydrogen-absorbing, oxygen-barrier, and water-barrier microcapsule according to claim 3, characterized in that: The solvent for the coating solution of the first coating layer is anhydrous ethanol and dichloromethane.

5. The method for preparing a three-layer coated hydrogen-absorbing, oxygen-barrier, and water-barrier microcapsule according to claim 2, characterized in that: The coating solution for the second coating layer is a polystyrene solution.

6. The method for preparing a three-layer coated hydrogen-absorbing, oxygen-barrier, and water-barrier microcapsule according to claim 5, characterized in that: The solvent for the polystyrene solution is dichloromethane.

7. The method for preparing a three-layer coated hydrogen-absorbing, oxygen-barrier, and water-barrier microcapsule according to claim 1, characterized in that: The coating solution for the third coating layer is a mixed solution of reduced graphene oxide and polystyrene, and the solvent is dichloromethane.

8. The method for preparing a three-layer coated hydrogen-absorbing, oxygen-barrier, and water-barrier microcapsule according to claim 7, characterized in that: The ratio of polystyrene to dichloromethane in the mixed solution of reduced graphene oxide and polystyrene is 1g:100-150mL, and the ratio of polystyrene to reduced graphene oxide is 100g:1-5g; the number of reduced graphene oxide layers is ≤3.

9. A three-layer coated hydrogen-absorbing, oxygen-barrier, and water-barrier microcapsule, characterized in that: The microcapsules were prepared using the method described in any one of claims 1-8, which involves three layers of coating to absorb hydrogen, block oxygen, and block water.

10. The hydrogen-absorbing, oxygen-barrier, and water-barrier microcapsules prepared by the method for preparing a three-layer coated hydrogen-absorbing, oxygen-barrier, and water-barrier microcapsule according to claims 1-8, or the application of the three-layer coated hydrogen-absorbing, oxygen-barrier, and water-barrier microcapsule according to claim 9, characterized in that: For hydrogen absorption in oxygen-containing environments or for hydrogen absorption in water-containing environments.

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