The power of photocatalytic filtration

what is photocatalytic filtration

Photocatalytic oxidation is a very powerful air purification technology that destroys microbes, volatile organic compounds (VOCs) and chemically active compounds.

As in chlorophyll photosynthesis, part of the UV rays of light (natural or artificial) activate titanium dioxide, which catalyzes the reactions of oxidation-reduction of organic substances absorbed on its surface: the compounds of organic origin are then degraded and the molecules, dismembered, return to their constituent elements: water vapor, carbon dioxide and minerals.

As a result of purification from said substances, photocatalytic filtration is highly effective in odor abatement.

To get an idea of the degree of effectiveness and effects, consider that photocatalytic filtration has the ability to destroy particles down to 0.001 microns while HEPA filters (commonly used in the medical field), can only retain particles down to 0.3 microns.

eco-friendly solution

We are all familiar with chlorophyll photosynthesis. It is the process by which plants transform water, mineral salts and carbon dioxide from the air into nutrients, while releasing oxygen.

For this transformation to occur, two elements are needed: a catalyst, chlorophyll, and light, which provides the energy to activate chlorophyll.

This is the meaning of
photosynthesis
(photo is the Greek word for light).

In photosynthesis, therefore, light infuses energy to chlorophyll which, subsequently, triggers the composition of carbon (C) of CO2, hydrogen (H) of H2O, oxygen (O) of O2 in the air and nitrogen (N) from fertilizer to CHON.

In photocatalytic filtration, titanium dioxide(TiO2, the ninth most common mineral on the planet, also known as white pigment) replaces the function performed by chlorophyll in chlorophyll photosynthesis.

Titanium dioxide-activated photocatalytic filtration is therefore a remarkably simple and natural form of reversing the contamination process, keeping surfaces clean and purifying the air.

Outside of filtration in the strict sense, examples of applications of photocatalysis activated by titanium dioxide are self-cleaning glasses and the so-called smog-eating asphalts .

Photosynthesis
Photosynthesis
Photosynthesis
Photosynthesis

when photocatalysis does not work

filtro cinese 2
Alibaba Filter

Chinese-made titanium dioxide treated filters available on AliBaba.

Why has photocatalytic filtration, which has been scientifically proven and has numerous advantages, not so far had significant commercial success?

Because it has been misapplied.

Photocatalytic filtration is generally performed by applying titanium dioxide to solid surfaces (such as a coating / paint) or by including it in the material itself.

Examples of commercial applications in this regard are filters made of ceramic or metallic material coated with titanium dioxide.

The limitations of these solutions are essentially 2:

  • the polluted air that is subjected to the purifying action is only that which comes into contact with the surface treated with titanium dioxide, and that is a minimum part of the total;
  • the contact time between the pollutant and titanium dioxide is not sufficient for photocatalysis to occur.

why depurex photocatalytic filtration works

Depurex uses a non-woven filter media with very high efficiency carbon microspheres treated with titanium dioxide that overcomes the criticalities highlighted.

The polluted air forcibly passes through the filter and then all comes into contact with the catalyst.

During the crossing, pollutants are retained by the coal microspheres.

The titanium dioxide with which the media is coated, irradiated by UV rays (natural or artificial), triggers photocatalysis that transforms pollutants into water vapor and carbon dioxide that evaporate, while the residual minerals are retained.

Since 2011 Depurex has been producing filters that use photocatalytic filtration for the needs of abatement of volatile organic compounds in atmospheric emissions or in applications for purification and sanitation of indoor pollution.

Depurex Photocatalytic Filter

Where to apply photocatalytic filtration

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