Magnesium carbonate ice nucleating agent

Abstract

The invention discloses methods and a composition for cloud seeding utilizing magnesium carbonate (MgCO3) particles as ice nucleating agents to enhance precipitation. The sub-micron to nano-sized MgCO3 particles, with lattice parameters approximating a ≈ 4.64 Å, b ≈ 4.64 Å, and c ≈ 14.93 Å, are introduced into the atmosphere via aircraft, generators, or rockets. Preferably bio-engineered through a green CO2 conversion process, these particles reduce carbon footprint, pose no environmental hazards per SDS regulations, and serve as plant nutrients. The invention extends to ice nucleation in artificial rain and ice recovery methods, offering a sustainable alternative for drought mitigation and climate change efforts.

Description

[0001] MAGNESIUM CARBONATE ICE NUCLEATING AGENT

[0002] FIELD OF INVENTION

[0003] This invention relates to cloud seeding technology, more particularly to the use of magnesium carbonate as an ice nucleating agent.

[0004] BACKGROUND OF INVENTION

[0005] Throughout the years, cloud seeding has emerged as a pivotal technology to combat water scarcity, particularly in regions suffering from prolonged droughts and unpredictable weather patterns. Cloud seeding involves introducing substances into the atmosphere that act as ice nuclei or cloud condensation nuclei to enhance precipitation. The efficacy of this technique has been well-documented across various countries, including the United States, China, Russia, Israel, and the United Arab Emirates, where extensive cloud seeding programs have been implemented successfully to increase rainfall and mitigate hail damage (Bruintjes, 2005; Henderson, 2006; Wang et al., 2006).

[0006] Traditional cloud seeding agents, such as silver iodide (Agl) and dry ice, have been extensively used due to their effectiveness in ice nucleation. Silver iodide (Agl), in particular, has been widely adopted due to its crystallographic lattice properties that closely resemble those of ice. The lattice parameters of Agl and solid H2O are almost identical, resulting in a minimal lattice mismatch that promotes efficient ice crystallization and growth on Agl seed clusters (Schaefer, 1946; Vonnegut, 1947). However, despite its effectiveness, Agl might present significant environmental and health concerns. Studies have shown that Agl particles might pose potential eco- toxicological risks at concentrations exceeding the threshold limit of 0.43 mM, raising concerns about its widespread and frequent use in cloud seeding operations (Fajardo et al., 2016; Standler & Vonnegut, 1972). Additionally, the cost of Agl is anticipated to increase significantly over the coming years if one consider its corresponding CGAR trend, further highlighting the need for alternative seeding agents that are both cost-effective and environmentally friendly.

[0007] The search for alternative cloud seeding agents has led to the exploration of various substances, including propane, super-saturated carbon dioxide (CO2) in the form of dry ice, potassium iodide (KI), and biological ice nucleators (BINs) (Vali, 1995; Christner et al., 2008; Malik et al., 2018). Despite the promising results of these alternatives, none have achieved the same level of efficacy and reliability as Agl. Therefore, the quest for a novel, effective, and sustainable ice nucleating agent continues to be a priority in the field of cloud seeding.

[0008] In this context, magnesium carbonate (MgCOs) has emerged as a promising candidate for cloud seeding applications. Recent studies have demonstrated that MgCOs, particularly in sub-micron to nano-scaled particles, exhibits a significant ice nucleation efficiency comparable to that of Agl The lattice parameters of MgCOs (a ~ 4.64 A, b ~ 4.64 A, and c ~ 14.93 A) are closely aligned with those of solid H2O, resulting in a relatively low lattice mismatch within the and directions (~3%) (Williams et al., 1992). This similarity facilitates effective ice nucleation, making MgCOs a viable alternative to Agl for cloud seeding purposes.

[0009] Moreover, MgCOs offers several advantages over traditional seeding agents. It is cost-effective, as it does not involve the use of silver iodide, and it can be synthesized using green bio-engineering processes in addition to established standard physical & chemical approaches. The green bioengineering incorporates CO2 conversion to carbonate, thereby reducing the overall carbon footprint (Mohamed et al., 2023). Additionally, MgCOs poses minimal environmental risks, as it is non-hazardous according to international SDS regulations, and can act as a plant nutrient and potential fertilizer, further enhancing its environmental benefits (Silva et al., 2023). Table 1 : The crystal lattice average parameters (,,<c>) & unit cell volume (V) of various compounds and the lattice A / , / , A<c> / <c> and volume A<V> / <V>, mismatch. It is an object of the invention to provide a novel ice nucleating agent for cloud seeding that at least alleviates some of the abovementioned drawbacks. By leveraging the unique properties of magnesium carbonate, this invention aims to offer a sustainable, cost-effective, and environmentally friendly solution for enhancing precipitation and mitigating the adverse effects of drought and water scarcity.

[0010] In summary, the present invention addresses the need for a new generation of ice nucleating agents that combine high efficacy with environmental sustainability. Through the use of bio-engineered MgCOs particles, this invention provides a promising alternative to traditional cloud seeding materials, paving the way for more effective and eco-friendly weather modification practices.

[0011] References:

[0012] 1. Bruintjes RT (2005) Critical issues in rainfall enhancement experiments via cloud seeding: past, present and future. International conference on: water, land and food security in arid and semiarid regions. Mediterranean Agronomic Institute, Valenzano-Bari (Italy), 6-11 September 2005. Pp 233-254.

[0013] 2. Henderson TJ (2006) Achievement in weather modification. Department of Atmospheric Studies, Abu Dhabi (UAE). pp 8-21.

[0014] 3. Wang G, Lou X, Hu Z, You L, Feng D, Zhang J, Shi A, Li S, Guo E, Wang Y, Fang W, Shi Y, Sun J (2006) Main achievements of Institute of Weather Modification. Department of Atmospheric studies, Abu Dhabi (UAE). Pp 131-141.

[0015] 4. Schaefer. V.I., The production of ice crystals in a cloud of supercooled water droplets, Science 104 (1946) 456-459.

[0016] 5. Vonnegut. B., The nucleation of ice formation by silver iodide, J. Appl. Phys. 18 (1947) 593-595.

[0017] 6. Fajardo, C., Costa, G., Ortiz, L.T., Nande, M., Rodriguez-Membibre, M.L., Martin, M., Sanchez-Fortun, S. (2016). Potential risk of acute toxicity induced by Agl cloud seeding on soil and freshwater biota, Ecotoxicology and Environmental Safety, Vol. 133, pp. 433-441. Standler, R.B., Vonnegut, B. (1972). Estimated Possible Effects of Agl Cloud Seeding on Human Health, Journal of Applied Meteorology, American Meteorological Society (1962-1982), Vol. 11 , No. 8, pp. 1388-1391. Vali, G., in Biological Ice Nucleation & its Applications, R.E. Lee Jr., G.J. Warren, L.V. Gusta, American Phytopathological Society Press, St Paul, MN, Ch. 1 (1995). Christner, B.C., Morris, C.E., Foreman, C.M., Cai, R., Sands, D.C. (2008). Ubiquity of Biological Ice Nucleators in Snowfall, Vol. 319, pp. 1214. Malik, S., Bano, H., Rather, R.A., Ahmad, S. (2018). Cloud Seeding; Its Prospects and Concerns in the Modern World, Int. J. Pure App, Vol. 6 (5), no. 2320-7051 , pp. 791-796. Silva, S., Dias, M.C., Silva, A.M.S. (2023). Potential of MgO and MgCO3 nanoparticles in modulating lettuce physiology to drought, Acta Physiologiae Plantarum, 45:31. Mohamed, H., Hkiri, K., Botha, N. et al. (2023). Room temperature bio-engineered multifunctional carbonates for CO2 sequestration and valorization, Sci Rep, 13, 16783. Chunyan Zhao, Yunhua Lu, Xuhui Zhao, Santosh Khanal, Shiai Xu (2020). Synthesis of MgCO3 particles with different morphologies and their effects on the mechanical properties of rigid polyvinyl chloride composites, Polymer-Plastics Technology and Materials. Williams, Q., Collerson, B., Knittie, E. (1992). Vibrational spectra of magnesite (MgCOs) and calcite-lll at high pressures, American Mineralogist, Vol. 77, pp. 1158-1165. White, W.B. (1974). The Carbonate Minerals, in: V.C. Farmer (Ed.), The Infrared Spectra of Minerals, Mineralogical Society, London, pp. 87-110. SUMMARY OF INVENTION

[0018] According to a first aspect of the invention, there is provided a method for cloud seeding, which may comprise the steps of: introducing magnesium carbonate (MgCOs) particles into the atmosphere, wherein the MgCOs particles may act as ice nucleating agents to enhance precipitation.

[0019] The MgCOs particles may be sub-micron to nano-scaled in size.

[0020] These particles may have lattice parameters of approximately a ~ 4.64 A, b ~ 4.64 A, and c ~ 14.93 A.

[0021] The MgCOs particles may be bio-engineered using a green process that involves CO2 conversion to carbonate.

[0022] This bio-engineered, green process may involve capturing CO2 from the atmosphere or industrial sources and converting it into magnesium carbonate through a series of chemical reactions.

[0023] The process typically begins with the absorption of CO2 by a solution containing magnesium ions. The CO2 reacts with the magnesium ions to form magnesium carbonate precipitates. These precipitates are then collected and processed to achieve the desired particle size and purity. This method not only produces MgCOs particles for cloud seeding but also helps in reducing the atmospheric concentration of CO2, thus contributing to the mitigation of climate change.

[0024] The MgCOs particles may be introduced into the atmosphere using aircraft, ground-based generators, or rockets fired from launching sites. They may be non-hazardous according to international SDS regulations and may act as a plant nutrient and potential fertilizer. The method may further comprise the step of minimizing the CO2 footprint by using MgCOs particles synthesized from CO2 conversion. This method may be particularly effective in coastal regions to increase precipitation.

[0025] According to a second aspect of the invention, the invention extends to a composition for cloud seeding, which may comprise: magnesium carbonate (MgCOs) particles as the active ice nucleating agent, wherein the MgCOs particles may be sub-micron to nano-scaled in size.

[0026] These particles may have lattice parameters of approximately a ~ 4.64 A, b ~ 4.64 A, and c ~ 14.93 A.

[0027] The MgCOs particles may be bio-engineered using a green process involving CO2 conversion to carbonate and may be non-hazardous according to international SDS regulations.

[0028] Additionally, the MgCOs particles may act as a plant nutrient and potential fertilizer.

[0029] According to a third aspect of the invention, the invention extends to a method for ice nucleation in artificial rain processes, which may comprise: using magnesium carbonate (MgCOs) particles as ice nucleating agents, wherein the MgCOs particles may be introduced into supercooled water clouds.

[0030] These MgCOs particles may be sub-micron to nano-scaled in size and may have lattice parameters of approximately a ~ 4.64 A, b ~ 4.64 A, and c ~ 14.93 A.

[0031] According to a fourth aspect of the invention, the invention further extends to a method for ice recovery, which may comprise the steps of: introducing magnesium carbonate (MgCOs) particles into the environment, wherein the MgCOs particles may promote ice nucleation and recovery. The MgCOs particles may be synthesized using a bio-engineered, green process involving CO2 conversion to carbonate. This process captures CO2, a major greenhouse gas, and transforms it into a useful material, thereby providing an environmental benefit beyond its primary application in cloud seeding and ice nucleation.

[0032] BRIEF DESCRIPTION OF THE DRAWINGS

[0033] The objects and features of the present invention will become fully apparent from the following description taken in conjunction with the accompanying drawings. Undertaking that these drawings depict only typical embodiments of the invention and are therefore, not to be considered limiting its scope, the invention will be described and explained with additional specifics and detail through the use of the accompanying drawings in which:

[0034] In the drawings:

[0035] Figure 1 - shows the principle of a typical cloud seeding approach by planes in accordance with an aspect of the invention;

[0036] Figure 2 - shows the crystallographic structure of magnesium carbonate (MgCOs), highlighting the lattice parameters that closely match those of ice;

[0037] Figure 3 - shows High Resolution Transmission Electron Microscopy images of MgCOs particles, illustrating their poly-disperse sizes, including sub- micronic and nano-scaled crystals;

[0038] Figure 4 - shows the room temperature background corrected X-ray Diffraction pattern of the MgCOs sample, confirming its crystallinity and the absence of hydrated versions;

[0039] Figure 5 - shows the room temperature Raman spectrum of the bioengineered MgCOs particles, indicating the vibrational modes that confirm the magnesite nature of the sample;

[0040] Figure 6 - shows the Infrared spectrum of MgCOs, displaying the IR active modes of un-hydrated and hydrated magnesite, further validating the magnesite composition; Figure 7 - shows the ice nucleation of pure H2O and that of FhO-MgCCh loaded droplets at various stages of growth, demonstrating the enhanced crystallization within the MgCOs loaded droplets;

[0041] Figure 8(a,b,c,d) - shows the continued dendritic ice growth in MgCOs loaded H2O droplets over time, indicating the effectiveness of MgCOs as an ice nucleating agent;

[0042] Figure 9(a,b,c) - shows the shape phase diagram equivalent of ice, illustrating the dendritic growth observed in the MgCOs loaded droplets;

[0043] Figure 10 - shows the growth dynamics of MgCOs loaded H2O droplets at various concentrations, exploring the optimal loading for ice nucleation;

[0044] Figure 11 - shows top and side views of initial and relaxed structures of water molecules on magnesite slabs, providing insight into the interaction at the molecular level; and

[0045] Figure 12 - shows the charge density difference of adsorbed water molecules on magnesite slabs, highlighting the electron density changes associated with the adsorption process.

[0046] DETAILED DESCRIPTION OF AN EXAMPLE EMBODIMENT

[0047] While various inventive aspects, concepts, and features of the invention may be described and illustrated herein as embodied in combination in the exemplary embodiments, these various aspects, concepts, and features may be used in many alternative embodiments, either individually or in various combinations and sub-combinations thereof. Unless expressly excluded herein, all such combinations and sub-combinations are intended to be within the scope of the present invention. Still further, while various alternative embodiments as to the various aspects, concepts, and features of the invention — such as alternative structures, configurations, methods, devices, and components, and alternatives as to form, fit, and function — may be described herein, such descriptions are not intended to be a complete or exhaustive list of available alternative embodiments, whether presently known or later developed.

[0048] Those skilled in the art may readily adopt one or more of the inventive aspects, concepts, or features into additional embodiments and uses within the scope of the present invention even if such embodiments are not expressly disclosed herein. Still further, exemplary or representative values and ranges may be included to assist in understanding the present disclosure; however, such values and ranges are not to be construed in a limiting sense and are intended to be critical values or ranges only if so expressly stated. Moreover, while various aspects, features, and concepts may be expressly identified herein as being inventive or forming part of an invention, such identification is not intended to be exclusive but rather there may be inventive aspects, concepts, and features that are fully described herein without being expressly identified as such or as part of a specific invention.

[0049] As can be seen in Figure 1 of the drawings, there is provided a typical cloud seeding approach by planes. This method involves the introduction of magnesium carbonate (MgCOs) particles into the atmosphere to act as ice nucleating agents. The MgCOs particles used in this invention are bio- engineered using a green process that involves the conversion of CO2 to carbonate. This process not only produces the MgCOs particles but also helps in reducing atmospheric CO2 levels, thereby contributing to climate change mitigation.

[0050] The MgCOs particles are characterized by their sub-micron to nanoscaled size, with lattice parameters of approximately a ~ 4.64 A, b ~ 4.64 A, and c ~ 14.93 A. These parameters are closely aligned with those of solid H2O, resulting in a relatively low lattice mismatch within the and directions (~3%). This similarity facilitates effective ice nucleation, making MgCOs a viable alternative to traditional seeding agents like silver iodide (Agl).

[0051] The introduction of MgCOs particles into the atmosphere can be achieved using various methods, including aircraft, ground-based generators, or rockets fired from launching sites. Figure 1 illustrates the principle of a typical cloud seeding approach by planes. The MgCOs particles are dispersed into the clouds, where they act as nuclei for ice formation. This process enhances precipitation, making it particularly effective in regions suffering from drought and water scarcity.

[0052] Figure 2 shows the crystallographic structure of MgCOs, highlighting the lattice parameters that closely match those of ice. The x-y lattice parameters of MgCOs are a ~ 4.64 A, b ~ 4.64 A, which are very close to those of ice (a ~ 4.5 A and b ~ 4.5 A), while the z direction (c ~ 14.93 A) is nearly twice that of ice (c ~ 7.3 A). The lattice mismatch in the x-y direction is <3%.

[0053] Figure 3 provides High Resolution Transmission Electron Microscopy images of the MgCOs particles, demonstrating their poly-disperse sizes, including sub-micronic and nano-scaled crystals. The particles appear as submicron thin flakes with sharp edges and nano-scaled crystals, which are trigonal in shape in accordance with the symmetry of MgCOs. The large surface to volume ratio of these particles bolsters ice nucleation due to the abundance of surface anchoring sites.

[0054] Figure 4 presents the room temperature background corrected X-ray Diffraction pattern of the MgCOs sample, confirming its crystallinity. The Bragg diffraction peaks correspond to single phase Magnesite (MgCOs) and align with the JCPDS 86-2345 card of pure Magnesite, indicating that any hydrated MgCO3 crystals are below the detection limit.

[0055] Figure 5 displays the room temperature Raman spectrum of the bioengineered MgCOs particles. The spectrum exhibits two intense and three low-intensity Raman vibrational modes located at approximately 299.1 , 505.9, 746.3, 879.9, and 1100.7 cm’1. The modes centered at 1100.7 cm’1and 746.3 cm’1are assigned to v1 COs symmetric stretch and v2 in-plane bend modes, respectively, confirming the magnesite nature of the sample.

[0056] Figure 6 shows the Infrared spectrum of MgCOs, displaying the IR active modes of both un-hydrated and hydrated magnesite. The spectral regions are observed at 400-2600 cm’1and 2600-4000 cm’1, respectively. The vibrational IR active modes are positioned at 788.3, 880.1 , 1413.4, 1578.1 , 482.8, 425.6, and 478.1 cm’1, validating the magnesite composition with the presence of some hydrated magnesite forms.

[0057] Figure 7 illustrates the ice nucleation of pure H2O and FhO-MgCOs loaded droplets at various stages of growth. The optical images of the unloaded pure H2O and the MgCOs loaded H2O droplets were taken at different time periods of crystallization: t = 0.1 , 1.2, 3.36, and 4.02 seconds. During the early ice nucleation period of about 4 seconds, there is a prompt crystallization within the MgCOs loaded H2O droplet compared to the pure H2O droplet, which appears relatively clear and quasi-transparent. The diffuse appearance of the MgCOs loaded droplet is likely due to significant light scattering by internal crystals formed within the droplet. Figure 8 continues to show the ice nucleation of pure H2O and H2O- MgCOs loaded droplets at various growth times. From t = 1 .2 seconds, the surface of the MgCOs loaded H2O droplet exhibits a significant population of dendritic ice segments. This dendritic ice growth continues uninterruptedly up to about 4.02 seconds, at which point both pure and MgCOs loaded droplets scatter light intensively, likely due to the larger dendritic population.

[0058] Figure 9 displays the shape phase diagram equivalent of ice. The dendritic growth observed in Figures 7 and 8 takes place on a dry ice surface with a temperature measured by pyrometry to be about ~ -3.7°C, corresponding to the gray area in the standard ice nucleation diagram.

[0059] Figure 10 shows the growth dynamics of MgCOs loaded H2O droplets at various concentrations (3.125%, 6.25%, 12.5%, 25%, 50%, and 100%). The variation of the droplets' diameter is quasi-linear with time for the various concentrations, deviating approximately as ( t) for the largest loading concentration (100%). Within this concentration, the average droplets size increases from ~1.0 mm to ~1.06 mm within 5 minutes, indicating a relative increase of 6%. Further optimization of this growth process would involve investigating smaller MgCOs particles, as dominantly nano-scaled MgCOs would allow faster and larger ice nucleation.

[0060] Figure 11 shows top and side views of the initial and relaxed structures of water molecules on magnesite slabs. It provides insight into the molecular interaction between water molecules and the magnesite surface.

[0061] Figure 12 shows the charge density difference of adsorbed water molecules on magnesite slabs, highlighting the electron density changes associated with the adsorption process. This detailed view helps in understanding the ice nucleation mechanism at the molecular level.

[0062] Henceforward, and within this contribution, it is validated that MgCOs is indeed a potential ice nucleus. The current bio-engineered MgCOs's major advantages relative to the preferred Agl can be summarized as follows: (i) Cost effectiveness: No silver, iodine, or their compounds are used.

[0063] (ii) Minimization of the eco-risk: MgCOs is non-hazardous according to international SDS regulations. (iii) Nutritional benefits: Mg is a plant nutrient and hence MgCOs could act as a potential fertilizer and as an additive for drinking water.

[0064] (iv) Minimization of the CO2 footprint: The process of making MgCOs involves CO2 and its conversion to carbonate, following a green bioengineering process. (v) Sustainable synthesis: MgCOs is synthesized using a green bioengineering process, including at its nanoscale, as demonstrated within this contribution and previously.

Claims

CLAIMS1. A method for cloud seeding comprising introducing magnesium carbonate (MgCOs) particles into the atmosphere, wherein the MgCOs particles act as ice nucleating agents to enhance precipitation.

2. The method of claim 1 , wherein the MgCOs particles are sub-micron to nano-scaled in size.

3. The method of claim 1 , wherein the MgCOs particles have lattice parameters of approximately a « 4.64 A, b « 4.64 A, and c « 14.93 A.

4. The method of claim 1 , wherein the MgCOs particles are bioengineered using a green process involving CO2 conversion to carbonate.

5. The method of claim 4, wherein the green process comprises capturing CO2 from the atmosphere or industrial sources and reacting it with magnesium ions to form MgCOs precipitates, which are then processed to achieve desired particle size and purity.

6. The method of claim 1 , wherein the MgCOs particles are introduced into the atmosphere using aircraft, ground-based generators, or rockets.

7. The method of claim 1 , wherein the MgCOs particles are non- hazardous according to international SDS regulations and act as a plant nutrient or potential fertilizer.

8. The method of claim 1 , further comprising minimizing CO2 footprint by using MgCOs particles synthesized from CO2 conversion.

9. The method of claim 1 , wherein the method is applied in coastal regions to increase precipitation.

10. A composition for cloud seeding comprising magnesium carbonate (MgCOs) particles as the active ice nucleating agent, wherein the MgCOs particles are sub-micron to nano-scaled in size.11 . The composition of claim 10, wherein the MgCOs particles have lattice parameters of approximately a « 4.64 A, b « 4.64 A, and c « 14.93 A.

12. The composition of claim 10, wherein the MgCOs particles are bioengineered using a green process involving CO2 conversion to carbonate.

13. The composition of claim 10, wherein the MgCOs particles are non- hazardous according to international SDS regulations and act as a plant nutrient or potential fertilizer.

14. A method for ice nucleation in artificial rain processes comprising using magnesium carbonate (MgCOs) particles as ice nucleating agents, wherein the MgCOs particles are introduced into super-cooled water clouds.

15. The method of claim 14, wherein the MgCOs particles are sub-micron to nano-scaled in size and have lattice parameters of approximately a « 4.64 A, b = 4.64 A, and c « 14.93 A.

16. A method for ice recovery comprising introducing magnesium carbonate (MgCOs) particles into the environment, wherein the MgCOs particles promote ice nucleation and recovery.

17. The method of claim 16, wherein the MgCOs particles are synthesized using a bio-engineered green process involving CO2 conversion to carbonate.

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