Exploring Zeolites and BioCote® Antimicrobial Technology

Exploring Zeolites and BioCote® Antimicrobial Technology

2.9 min readPublished On: April 10th, 2024By
2.9 min readPublished On: April 10th, 2024By
What are zeolites

What are zeolites?

Zeolites are interesting compounds chemically classified as aluminosilicates, composed of aluminium, silicon, and oxygen. The possess a unique chemical structure and properties and contain a variety of alkali and alkaline earth metals -such as sodium, potassium, calcium, and magnesium. There are at least forty natural zeolites, with synthetic types increasing the total to in excess of two hundred.

The Genesis of Zeolites

The origins of the name “zeolite” stems from the Greek words for “boiling” and “stone”, a nod to their characteristic ability to swell when heated as discovered by Swedish geologist Axel Cronstedt, which he would call ‘zeolit’ with a blowpipe, causing the mineral to boil and swell (Colella and Gualtieri, 2007). The structure of these compounds typically consists of molecular sized pores that can trap/hold water, at various quantities, adsorbed onto their complex internal surfaces.

Zeolite Versatility Through Structure

One of the impressive features of zeolites is their pore structure, an exceptionally fine porous structures enable them to function as molecular sieves. This means they are able to separate chemical compounds based on their size. They can also function as ion exchange, catalytic, and carrier materials thanks to their unique combination of physical structure and chemical composition. The primary consideration of zeolites in their functionality is their pores, and it has been calculated that just ten grams of the natural zeolite chabazite, has a comparable surface area to that of a standard sized football pitch, which is approximately 5,000 square metres.

Zeolites and Antimicrobial Properties

In recent years, zeolites have gained attention for their antimicrobial properties. Silver known for its stability and broad spectrum of antimicrobial affects and is commonly used in the exchange process (Kwakye-Awuah et al, 2008). Zeolites are able to provide a unique platform for silver storage and release. Their aluminosilicate framework functions as ion-exchange agents, allowing varying amounts of silver ions (Ag+) to be stored within.

Furthermore, the release characteristics can be tailored based on the zeolite type and the ionic strength of the surrounding medium (Malachova et al, 2011). Alternative metal ions like zinc and copper can also be used in the ion exchange procedure for the modification of zeolites to provide them with antimicrobial properties.

Sorption in Zeolites for Antimicrobial Properties

One of the key attributes of zeolites is their negative charge, which makes theme excellent for sorption – the ability to absorb and hold onto other substances. This is particularly useful for carrying materials with antimicrobial properties, such as silver ions. The aluminosilicate framework of zeolites has a permanent negative charge due to isomorphous substitution, which is the process of replacing one structural cation for another of a similar size. This negative charge is balanced by exchangeable cations. Because of their porous structures, zeolites have excellent sorption properties, which supports their function as carriers of materials, including those with inherent antimicrobial efficacy such as Ag+.

BioCote® antimicrobial technology exerts, by various modes of action, an inhibiting effect on the growth of odour, staining and material degrading microorganisms, such as MRSA and E. Coli, at levels of up to 99.9%. BioCote® reduces the likelihood of cross-contamination between surfaces, complimenting any existing cleaning practices.

References

Colella, C.; Gualtieri, A.F;. Cronstedt’s Zeolite, Microporous Mesoporous Mater. 2007, 105, 213–221. https://doi.org/10.1016/j.micromeso.2007.04.056

Kwakye-Awuah, B.; Williams, C.; Kenward, M.; Radecka, I. Antimicrobial action and efficiency of silver-loaded zeolite X. J. Appl. Microbiol. 2008, 104, 1516–1524

Malachová, K.; Praus, P.; Rybková, Z.; Kozák, O. Antibacterial and antifungal activities of silver, copper, and zinc montmorillonites. Appl. Clay Sci. 2011, 53, 642–645.

Evolving EU Biocidal Products Regulation: Updates on Silver Zinc Zeolite

At the recent 50th Biocidal Products Committee (BPC-50) meeting held in February 2024, Silver Zinc Zeolite received positive support for approval as an active substance under multiple Product-types (PTs), including disinfectants (PT2), film preservatives (PT7), and fibre, leather, rubber, and polymerised materials preservatives (PT9. This endorsement signifies a crucial step towards regulatory acceptance.