Semiconductor Photocatalysis Test Applications

Uses for Photocatalysis Tests

The current ISO standards for photocatalysis span five different test categories, reflecting the different applications, which are listed in the table below:

Test Category	Test pollutant	ISO standard reference number	Suitable sample types and applications
Air Purification	NO	ISO 22197-1:2016	Exterior: NO_x removing paint, concrete and tiles; Interior: odour-removing paint.
	Acetaldehyde	ISO 22197-2:2011
	Toluene	ISO 22197-3:2011
Water purification General	Methylene blue* Rz Ink Test	ISO 10678:2010 ISO 21066:2018	Water purification units General purpose test for non-porous smooth flat photocatalytic materials such as glass, paint, concrete, awning materials and tiles
Self-cleaning	Contact angle/Oleic acid	ISO 27448:2009 ISO 19810: 2017	self-cleaning glass, concrete, tent/awning materials and tiles
Self-cleaning	Methylene blue*	ISO 10678:2010
Photosterilisation	Bacteria	ISO 27447:2009	Photo-induced sterile surfaces
Light Sources	n/a	ISO 10677:2011	Photo-induced sterile surfaces

*Methylene blue is suggested by ISO 10678: 2010 as a test method for self-cleaning surfaces; however, we believe it is equally appropriate (maybe more so) as a water-purification test, thus its double entry in the above table. At IPS we use all but the photosterilisation ISO standards listed in the above table to test and provide confidential reports on photocatalyst samples provided by our customers. If you are unsure which standard(s) to apply to your sample, contact us for advice and information.

Further Information

Semiconductor photocatalysis has many uses, such as: the photomineralisation of volatile and non-volatile organics and (to a lesser extent) inorganics, photoinduced superhydrophilicity and photosterilisation. In addition to its wide range of application, the process also benefits from having a few significant semiconductors, such as titanium oxide, that are extremely robust, both chemically and photochemically, and inexpensive. Therefore, a number of notable different commercial products have arisen from the wide-scale research conducted in this area.

These include: (i) self-cleaning glass, concrete, tent/awning materials and tiles, (ii) odour-removing paint for indoor applications, (iii) NO_x removing paint, concrete and tiles for exterior applications, (iv) photo-induced sterile surfaces (ceramics and metals), (v) water and air purification units and (vi) defogging mirrors.

Accordingly, due to strong demand for test methods which enable correct evaluation of their performance, there are currently eight ISO standards, covering air and water purification, self-cleaning and antibacterial action, and light standards. These published standards address the need for the quantification of the activities of such semiconductor photocatalytic materials.