ISO 22197-4:2013 Formaldehyde removal
ISO 22197-4: 2013 – Test method for air-purification performance of semiconducting photocatalytic materials. Part 4: Removal of formaldehyde.
The test piece, put in a flow-type photoreactor, is activated by UV illumination, and adsorbs and oxidizes gas-phase formaldehyde to form carbon dioxide (CO2) and other oxidation products. Typical test conditions are given below:
|5 cm x 10 cm and typically 5 mm thick
|Suitable sample type
|Construction materials in flat sheet, board or plate shape; structured filter materials including honeycomb-form; woven and non-woven fabrics; plastic or paper materials if they contain ceramic microcrystals and composites.
|Unsuitable sample type
|Powder or granular photocatalytic materials
|16-24 hr UV irradiation at ≥ 1.5 mW/cm2
|3 L min-1 of 1 ppm formaldehyde in air, adjusted to 50% RH; time: 3 hours; irradiance: 1 mW/cm2; temp: 25 °C
|Amount of formaldehyde removed (mmol) and % formaldehyde removed
For the best evaluation of air purification performance of photocatalytic materials, it is recommended by ISO to combine one or more of the Air Purification test methods.
These methods are designed to obtain the air-purification performance of photocatalytic materials by exposing a test piece to model polluted air, in a photoreactor, under illumination by ultraviolet (UV) light. The concentration(s) of the analyte(s) of interest are monitored regularly and the concentration versus time data profile(s) are then processed so as to provide one or more measures of the efficiency of the test piece to remove photocatalytically the air-pollutant under test.