Can a construction material remove pollutants from the air as it keeps its surface clean?
De-pollution means the removal of contaminants and impurities from the environment. The newest tool for achieving de-pollution is a photocatalyst.The photocatalytic cement contains photocatalytic components which use the energy from ultraviolet rays to oxidize most organic and some inorganic compounds. Air pollutants that would normally result in discoloration of exposed surfaces are removed from the atmosphere by the components and the residues are washed off by rain.
The primary ingredient of smog, ozone is an extremely reactive gas molecule that reacts chemically with lung tissue, causing decreased lung function, respiratory infection, lung inflammation, and aggravation of respiratory illnesses.
The raw ingredients for ozone are nitrogen oxides (NOX)—produced primarily by internal combustion engines—and volatile organic compounds (VOCs)— hydrocarbons that have evaporated from chemical Concrete that Cleans Itself and the Air Photocatalytic cement helps oxidize pollutants plants, refineries, factories, gas stations, and points. Ozone is created when the two raw ingredients are combined in the presence of heat and sunlight.
A building with photocatalytic precast concrete cladding can do the same. Because the proprietary compound oxidizes both NOX and VOCs, it combats ozone at the source. Other chemicals are known to be oxidized using photocatalytic cement include:
The final products of the reactions include harmless quantities of nitrates and sulfates. Studies have shown that these by-products are negligible and do not contribute significantly to soil and groundwater nitrification.
Interestingly, it’s expected that the best results from photocatalytic cement will be obtained in the worst pollution conditions.
Photocatalysts accelerate the chemical reaction whereby strong sunlight or ultraviolet light decomposes organic materials in a slow, natural process.* When used on or in a concrete structure, photocatalysts decompose organic materials, biological organisms, and airborne pollutants. Dirt, soot, mould, bacteria and chemicals that cause odours are among the many substances that are decomposed by photocatalytic concrete. These compounds break down to have a minimal impact on the environment.
Titanium dioxide (TiO2), a white pigment, is the primary catalytic ingredient and can be incorporated in the cement manufacturing process. When activated by the energy in light, the white pigment creates a charge that disperses on the surface of the photocatalyst and reacts with external substances to decompose organic compounds.
Photocatalytic cement has other environmental benefits, such as reflecting much of the sun’s heat and reducing the heat gain associated with dark construction materials. This keeps cities cooler, reduces the need for air-conditioning and reduces smog.
This cement can be used to produce concrete and plaster products that save on maintenance cost while they ensure a cleaner environment. Designing projects with photocatalytic precast concrete also help to promote aesthetic endurance, keeping the structure looking like new over time.In addition to Portland cement binders, the product contains photo-catalytic titanium dioxide particles.
Photocatalytic cement is already being used for sound barriers, concrete paver blocks, and façade elements. Other applications include:
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