Zeolites; the Good, the Bad and the Ugly….
Zeolites are a class of naturally occurring or synthetic hydrated aluminosilicate minerals with a unique crystalline structure. They have a wide range of applications, including in catalysis, adsorption, ion exchange, and as molecular sieves. When discussing “safe” versus “unsafe” zeolites, the context typically revolves around their potential health effects and environmental impact.
Most Zeolite used in industry do not occur naturally[i]. For each structure, the International Zeolite Association (IZA) gives a three-letter code called framework type code (FTC) for identifying/categorizing Zeolite(s)[ii]. For example, the major molecular sieves, 3A, 4A and 5A, are all LTA (Linde Type A). Most commercially available natural zeolites are of the MOR, HEU or ANA-types.
When Zeolites are attacked by individuals claiming they are not safe, they will always point to a study that is using a synthetic Zeolite. or a highly modified natural Zeolite. You can turn any inert substance into a deadly one, example? Add cyanide to saline solution and drink, or inject it. This is no different than coating a natural Zeolite with graphene oxide[iii] then adding it to a drink, or injecting it into the body. Apples are not Oranges.
The Good Zeolites:
Many naturally occurring zeolites, such as clinoptilolite and chabazite, are considered safe for various applications. These zeolites are often mined. These zeolites are generally regarded as safe for human and animal consumption when used appropriately. For example, clinoptilolite zeolite is commonly used in dietary supplements, and is also used on animal feed to improve digestion and nutrient absorption without adverse effects[iv]. It does not breakdown in the body[v].
They also pose minimal risk to the environment. They are often used in soil remediation projects to adsorb heavy metals and other contaminants, helping to clean up polluted sites without causing further harm.
Many safe zeolites have received regulatory approval for specific applications. For instance, certain zeolites are listed as Generally Recognized as Safe (GRAS) by the U.S. Food and Drug Administration (FDA) for use in food and dietary supplement products[vi]–[vii].
Safe zeolites, such as clinoptilolite exhibit beneficial properties such as high surface area, thermal stability, and selective adsorption capabilities, making them valuable in various scientific and health related applications.
The Maya culture of Mesoamerica used natural zeolite for water purification purposes. During 1176 BC to 924 BC, Tikal’s Corriental reservoir served as one of the largest storage facilities for Maya drinking water. Remarkably, it featured an apparent zeolite filtration system, making it the oldest known instance of water purification in the Western Hemisphere and the earliest documented use of zeolite for decontaminating drinking water globally[viii]–[ix].
The Bad Zeolites:
Synthetic Zeolites: Some synthetic zeolites may contain harmful components or impurities that pose risks to human health and the environment. For example, zeolites synthesized using toxic chemicals or with inadequate purification processes may retain traces of contaminants.
Unsafe zeolites may pose health risks when ingested, inhaled, or exposed to the skin. Inhalation of fine zeolite particles, especially those with fibrous or needle-like structures, can lead to respiratory, and other issues. Unlike natural zeolites, synthetic zeolites can breakdown in the body of mammals[x].
Unsafe zeolites may contribute to environmental contamination if not properly handled or disposed of. Contaminants leaching from poorly manufactured or impure zeolite products can pollute soil, water, and air, posing risks to ecosystems and human health. This is the exact opposite of what natural zeolite can accomplish, which are used effectively in water filtration.
The composition and purity of zeolite materials significantly influence their safety profile. Zeolites with high levels of purity and minimal impurities are generally safer for use in various applications.
In summary, while many zeolites are safe for various applications, certain synthetic or impure zeolites may pose health and environmental hazards. Understanding the composition, purity, and potential risks associated with different types of zeolites is essential for selecting safe materials and implementing appropriate safety measures in industrial, agricultural, and other applications.
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Citaions
[i] https://en.wikipedia.org/wiki/Zeolite#cite_note-IZA-SC-4
[ii] Database of Zeolite Structures”. iza-structure.org. International Zeolite Association. 2017. Retrieved 24 May 2021.
[iii] Energy Fuels 2023, 37, 22, 17013–17051 Publication Date:October 26, 2023 https://doi.org/10.1021/acs.energyfuels.3c02546
[iv] Kraljević Pavelić S, Simović Medica J, Gumbarević D, Filošević A, Pržulj N, Pavelić K. Critical Review on Zeolite Clinoptilolite Safety and Medical Applications in vivo. Front Pharmacol. 2018 Nov 27;9:1350. doi: 10.3389/fphar.2018.01350. PMID: 30538633; PMCID: PMC6277462.
[v] Kraljević Pavelić S, Simović Medica J, Gumbarević D, Filošević A, Pržulj N, Pavelić K. Critical Review on Zeolite Clinoptilolite Safety and Medical Applications in vivo. Front Pharmacol. 2018 Nov 27;9:1350. doi: 10.3389/fphar.2018.01350. PMID: 30538633; PMCID: PMC6277462.
[vi] Cristian C. Villa, Germán Ayala Valencia, Alex López Córdoba, Rodrigo Ortega-Toro, Shakeel Ahmed, Tomy J. Gutiérrez,Zeolites for food applications: A review, Food Bioscience,Volume 46,2022,101577,ISSN 2212-4292
[vii] https://www.science.org/content/article/maya-built-western-hemisphere-s-first-water-filtration-system
[viii] Tankersley, Kenneth Barnett, Dunning, Nicholas P., Carr, Christopher, Lentz, David L., Scarborough, Vernon L. Zeolite water purification at Tikal, an ancient Maya city in Guatemala, 2020, 2020/10/22, Scientific Reports, 18021, 10,2045-2322, https://doi.org/10.1038/s41598-020-75023-7, 10.1038/s41598-020-75023-7
[ix] https://www.science.org/content/article/maya-built-western-hemisphere-s-first-water-filtration-system
[x] Çelikbaş İ, Mavi E, Hepokur C. The evaluation of the effects of natural zeolite (Clinoptilolite) in diabetic rats on bone healing in dental extracting socket. J Oral Biol Craniofac Res. 2023 Jan-Feb;13(1):36-40. doi: 10.1016/j.jobcr.2022.10.007. Epub 2022 Oct 26. PMID: 36353678; PMCID: PMC9638813.
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[i] Kraljević Pavelić S, Simović Medica J, Gumbarević D, Filošević A, Pržulj N, Pavelić K. Critical Review on Zeolite Clinoptilolite Safety and Medical Applications in vivo. Front Pharmacol. 2018 Nov 27;9:1350. doi: 10.3389/fphar.2018.01350. PMID: 30538633; PMCID: PMC6277462.
[ii] Kraljević Pavelić S, Simović Medica J, Gumbarević D, Filošević A, Pržulj N, Pavelić K. Critical Review on Zeolite Clinoptilolite Safety and Medical Applications in vivo. Front Pharmacol. 2018 Nov 27;9:1350. doi: 10.3389/fphar.2018.01350. PMID: 30538633; PMCID: PMC6277462.
[iii] Cristian C. Villa, Germán Ayala Valencia, Alex López Córdoba, Rodrigo Ortega-Toro, Shakeel Ahmed, Tomy J. Gutiérrez,Zeolites for food applications: A review, Food Bioscience,Volume 46,2022,101577,ISSN 2212-4292
[iv] https://www.science.org/content/article/maya-built-western-hemisphere-s-first-water-filtration-system
[v] Tankersley, Kenneth Barnett, Dunning, Nicholas P., Carr, Christopher, Lentz, David L., Scarborough, Vernon L. Zeolite water purification at Tikal, an ancient Maya city in Guatemala, 2020, 2020/10/22, Scientific Reports, 18021, 10,2045-2322, https://doi.org/10.1038/s41598-020-75023-7, 10.1038/s41598-020-75023-7
[vi] https://www.science.org/content/article/maya-built-western-hemisphere-s-first-water-filtration-system
[vii] Çelikbaş İ, Mavi E, Hepokur C. The evaluation of the effects of natural zeolite (Clinoptilolite) in diabetic rats on bone healing in dental extracting socket. J Oral Biol Craniofac Res. 2023 Jan-Feb;13(1):36-40. doi: 10.1016/j.jobcr.2022.10.007. Epub 2022 Oct 26. PMID: 36353678; PMCID: PMC9638813.