Sanitizing environments, as we know by now, is essential, whether it is the sanitization of healthcare environments – hospitals, dental offices, outpatient clinics, or industrial environments – the food industry, for obvious reasons, is in the lead to this list. 

Of course, sanitizing is important, but so is respecting the environment, even if it is not always possible: Among the zero-impact technologies AMIL Care uses is photocatalysis, which we will briefly explain. 

Photocatalysis: what it is and how it works

Let’s start by understanding what the photocatalysis process consists of. First of all, it should be specified that photocatalysis is a natural process, that occurs in nature, and which is developed using light to “transform” substances harmful to humans. 

If we had to give it a scientific definition, then we would say that the meaning of photocatalysis consists in the action of some semiconductor materials, for example, zinc oxide and titanium dioxide, which under the action of light can cause reduction or oxidation of harmful substances, also present in small quantities. 

This peculiarity can be used in many ways: for example, photocatalysis is used to protect the surface of building coatings, preserving their value and shape for a longer time. 

Photocatalysis is the acceleration of the oxidation of some organic and inorganic substances through an element, called a catalyst, which in some cases determines the removal of harmful substances from the air. This natural phenomenon is mainly activated by light and occurs in the presence of photocatalysts. 

A photocatalyst is an element capable of promoting a chemical reaction by absorbing electromagnetic radiation. The photocatalyst is neither modified nor consumed by a chemical reaction. 

In a certain sense, we can say that photocatalysis imitates the process of chlorophyll photosynthesis. As occurs in plants, which absorb carbon dioxide and release oxygen, photocatalysis transforms substances harmful to humans into harmless ones. 

The advantages of photocatalysis

Photocatalysis is part of a series of processes defined as Advanced Oxidation Processes (AOPs): This means precisely that photocatalysis generates chemical species with a high oxidizing power capable of degrading molecules of pollutants present in the atmosphere. 

The biocidal effect of photocatalytic oxidation can be attributed to photogenerated holes in the valence band, hydroxyl radicals, hydrogen peroxide, and other reactive oxygen species. 

“Photocatalytic oxidation (PCO) is a recently developed air and surface cleaning technology, which has the unique ability to destroy both microorganisms and microbial volatile organic compounds (VOCs).” 

Photocatalysis has several advantages that should not be underestimated. It significantly degrades the recalcitrant pollutants present in the air and in the water. 

The pollutant is mineralized to CO2 and H2O and not transferred to another phase. 

The whole process is cheap and does not require regeneration, it is not selective, it can eliminate pollutants of various kinds, and it exploits what is most abundant in nature, i.e., light and water (in the case of air: humidity). 

The photocatalytic process is therefore a completely natural, anti-pollution, anti-dirt, and antibacterial process. 

How can photocatalysis have a bactericidal effect?

The bactericidal effect of photocatalytic action is due to the formation of Reactive Oxygen Species (ROS), generated by the synergistic photocatalyst-light system. 

Hydroxyl radicals and superoxide ions are highly reactive species that oxidize VOCs, which either adsorb onto the catalyst surface or come into contact so close that they react chemically. They deactivate and decompose viruses, bacteria, and fungi. 

Simply put, hydroxyl radicals are the basis of the most powerful advanced oxidation systems. They are highly powerful oxidizing agents capable of sanitizing, deodorizing, and purifying the air, water, and various surfaces. 

Since they have an extremely short duration, hydroxyl radicals must be generated near the membrane, so that they are able to oxidize some of its components: This characteristic, together with the fact that they have an extremely short lifetime, makes them harmless to health. 

AMIL Care uses tungsten trioxide to trigger photocatalysis 

Among its numerous sanitizing systems, AMIL Care uses tungsten trioxide (WO3) as an antibacterial agent to trigger photocatalysis. 

Tungsten trioxide (WO3) is more effective than any other antibacterial agent because the photocatalytic reaction takes place even when there are cells covering the surface and the multiplication of bacteria is active. 

Tungsten trioxide does not degrade and shows a long-term antibacterial effect. In general, disinfection with tungsten trioxide is more effective than that obtained with chlorine and ozone. It is up to 20 times more effective than the traditional TiO2 used in classic photocatalysis devices, it is activated with light in the visible spectrum; therefore, it does not require UV rays (as opposed to titanium dioxide), which are notoriously harmful to humans. 

How does photocatalysis happen? The process is very simple and requires three elements: tungsten trioxide (WO3), LED light, and of course, air. 

The LED light activates the photocatalysis process in the air. These two elements, together with tungsten trioxide (WO3), trigger a strong oxidative process, which causes tungsten trioxide to produce ROS (Reactive Oxygen Species), which allows the decomposition and transformation of bacteria (Gram-, Gram+), viruses, fungi and other polluting organic substances into harmless substances. This process has zero environmental impact. 

Photocatalysis with LED lamps and tungsten trioxide is a process that can easily be activated in the presence of people. It has a non-stop biocidal activity, does not require any type of maintenance and, as we have said, has no environmental impact.