BS ISO 22197-2:2011 pdf download

BS ISO 22197-2:2011 pdf download.Fine ceramics (advanced ceramics, advanced technical ceramics)—Test method forair-purification performance of semic onducting photocatalytic materials Part 2: Removal of acetaldehyde.
8.5.4 Supply zero-calibration gas with 1.56 % volume fraction of water vapour at 25,0 C ± 2.5 C and measure the concentration of CO2. Make sure that the concentration of CO2 is low and stable. Measure the concentration of CO2 under illumination. Then turn the light off, and measure the concentration of CO2 again. If the difference of CO2 concentration is less than I iJlIl between measurement with the light on and off, move forward to the next step. If a large amount of CO2 is observed to generate wtien the light is turned on, it is conceivable that the test piece is not well pretreated and is contaminated with organic matter, or the binder in the test piece has been decomposed by UV irradiation. When the previously cited condition is not met even after pretreatment of enough UV wradiance, etc., then do not measure the CO2 conversion (proceed to 8.6) and report that the test piece is not stable after pretreatment.
The change of CO2 concentration in 30 mm shall be no higher than 0.1 phi.
8.5.5 Get ready for measurement using the procedure described in 8.3.1.
8.5.6 lIthe pretest has been done, supply the test gas into the photoreactor until the time of the dark condition (adsorption) which has been checked beforehand (if the time is less than 30 mm, supply for 30 mm) arid mease the concentration of CO2. If the pretest has not been done, proceed as follows. At first, supply the test gas to the photoreaclor, and rcord the change in the concentrations of acetaldehyde and CO2 under the dark condition, to examine the adsorpUvily of the lest piece in 30 mm. However, if the concentration of acetaldehyde is less than 90 % of the supply gas concentration after 30 mm. continue until it exceeds this percentage. II the concentration does not exceed 90 % after 90 mm, stop measurement and report that this test is not applicable to the test piece used. The average of CO2 concentrations measured for the last 30 mm (more than 2 points) is to be the concentration of CO2 (4’O2re) under the dark condition before UV irradiation.
8.5.7 Mamntam the gas flow and commence irradiation of the test piece, and record the concentration of acetaldetmyde and CO2 under pho(oirradiation for 3 h continuously. As photocatalylic decomposition of acetaldetlyde occurs, the concentration of acetaldehyde lowers and the concentration of CO2 grows as shown in Figure 4. and they become stable in time. Continuous measurement of the concentrations is desired:
however. if there is a limitation for the number of measurements, at least I point of measurement within I h has to be done. In addition, more than 3 poInts of measurement have to be done m the last I h (120 mm to 180 mm after irradiation). The concentration of acetaldehyde (%) to be used for calculation of removal rate and the concentration of CO2 (#> ) is to be the mean value (more than 3 points) of the concentration measured during the last 1 h. If the relative standard deviation of the last 3 measurements of A exceeds 20 %. report this instability with possible reasons, such as deactivation of the test piece.
8.5.8 Stop photoirradiation, bring back to the dark condition and measure the concentration of CO2. After the concentration of CO2 has settled, the mean value (for more than 2 points) dunng this 30 mm period is reported as the CO2 concentration under dark conditions after UV irradiation
The change of CO2 concentration In 30 mm shall be no higher than 0.1 p1!).
8.5.9 Stop the test gas supply to the reactor, and remove the test piece from the reactor.
8.6 Test of acetaldehyde removal (when the CO2 concentration cannot be measured)
8.6.1 Pretreat the test piece and prepare for the test according to 82 and 8.3.
8,6,2 If the pretest (8,4) was done, allow the test gas to flow into the photoreactor until the time of the adsorption (dark condition) which had been determined beforehand lithe pretest was not done, do as follows Supply the test gas to the piiotoreactor for 30 mm under the dark condition, and measure the concentration of acetaldetlyde. Start photoirradiation when the concentration of acetaldehyde becomes the same as the supply gas concentration. If the concentration of acetaldehyde is less than 90 % of the supply gas concentration after 30 min, continue until it exceeds this percentage. If the concentration does not exceed 90 % after 90 min, stop measurement and report that this test method is not applicable to this test piece.