Category: Filters

The odour removing Mitsubishi Electric MAC-3000FT-E filters are made from a fine aluminum honeycomb with a catalyst coating of manganese dioxide (MnO₂) and silicon dioxide (SiO₂).

Manganese dioxide (MnO₂) and silicon dioxide (SiO₂) can work together synergistically for odour removal in air or water purification systems, especially by leveraging their catalytic and absorptive properties.

Manganese Dioxide (MnO₂) – Catalytic oxidation

MnO₂ is a strong oxidizing agent and acts as a catalyst in the breakdown of odorous compounds, especially volatile organic compounds (VOCs) and sulfur-containing compounds (like H₂S or mercaptans).
Mechanism: It promotes the oxidation of odorous molecules into less volatile or non-smelly compounds (like turning H₂S into elemental sulfur or SO₂).

Silicon Dioxide (SiO₂) – Adsorption medium

SiO₂, especially in the form of amorphous silica or silica gel, is highly porous and has a large surface area, making it excellent at adsorbing: Moisture, VOCs, and some odorous organic molecules.
While SiO₂ doesn’t chemically break down the molecules, it traps them physically—delaying or reducing their release into the air.

Together SiO₂ captures odorous molecules, giving MnO₂ time and proximity to oxidize them.

‘Apple catechin’ as found in ductless mini-split air filters refers to a type of natural antibacterial and antiviral coating used on air filter media. Catechin is a type of flavonoid, a naturally occurring antioxidant found in green tea, apples, and other plants. In air filters, apple catechin is typically infused into the filter fibers to enhance its ability to trap and neutralize bacteria, viruses, and odours.

How It Works

• Antibacterial Properties: Catechin can inhibit the growth of bacteria on the filter surface.
• Antiviral Effects: It has some potential to inactivate certain viruses.
• Odor Control: Catechin can help reduce unpleasant smells caused by organic compounds.
• Natural and Safe: It’s derived from apples or other plant sources, making it a more environmentally friendly and health-conscious option compared to synthetic chemical treatments.

Where You’ll See It

Apple catechin filters are most commonly found in:

• Residential air purifiers (especially in Japanese or Korean brands like Mitsubishi Electric, Fujitsu General, Daikin, Panasonic, or Sharp).
• Some HVAC systems (mainly in systems that emphasize air quality and health benefits).
• Air conditioning units (especially those marketed toward allergy sufferers or health-conscious consumers).

Does It Work?

It can be effective as a supplementary filter treatment, but it’s usually combined with other filtration technologies (like HEPA filters, activated carbon, or ionizers). On its own, apple catechin coating won’t replace mechanical filtration — it just adds a natural, passive layer of protection.

Mitsubishi Electric Catechin Brochure which provides more information:

Anti-allergy enzyme filters are filters that contain enzymes that help to eliminate allergens from the air. These filters are often used in air purifiers and HVAC systems. The enzymes in these filters are specifically designed to break down proteins found in common allergens such as pet dander, pollen, and dust mites. The broken down proteins are then trapped in the filter, reducing the amount of allergens in the air. This can help to reduce the symptoms of allergies, such as sneezing, itching, and watery eyes, for people with allergies or sensitivities. Anti-allergy enzyme filters are a safe and effective way to improve indoor air quality for those with allergies.