Mobirise

Purifying Efficiency of the Models Developed

Testing of purifiers in a closed chamber in a modified form serves as a standard measurement of the effectiveness of the final product, but also for further development of the purifiers.

RETAP has currently introduced 5 models designed to purify air in the volumes from about 30-150 m3



Photo and chart of testing the effectiveness of one of the first prototypes of RETAP nanopurifier according to CEN standard in Belgium. Test of organic compound mixtures consisting of formaldehyde, acetaldehyde, acetone, n-heptane, toluene and o-xylene with a volume concentration of 200 ppb.

The chart shows the degradation of chemicals formaldehyde, acetaldehyde, acetone, n-heptanemu, toluene and o-xylene with a volume concentration of 200 ppb at the time of 1.4 h to zero.

Scheme of the measuring chamber or box for experimental testing of active or passive photocatalytic air purification device. Inside is shown the photocatalytic device, e.g. purifier (black box) and a fan (cross) in the case of passive devices, i.e., photocatalytic coatings.

Photo of the purifier prototype in a box assembled at the TUL laboratory

The prototype of the air purifier was displayed during the international conference and ISO meeting in Prague in September 2014.

Technical Report on the Conclusions of Testing in 2014
Testing, designed and modified according to CEN method - degradation of toluene
Testing of the purifiers takes place in the above-mentioned experimental boxes. Before each test, the box is first thoroughly purged with air that has been filtered in advance. Thus filtered air contains a negligible amount of organic substances. In the liquid phase, the box is injected with a defined quantity of the studied volatile organic compounds (e.g. toluene, formaldehyde). The quantity of sprayed volatile substances is determined according to the required concentration (ppmv) in the box. Analysis of the gases in the box is performed using the photoacoustic apparatus INNOVA 1421i from LumaSense Technologies. This is the photoacoustic detection of infrared radiation that is absorbed by the sample in the gas. Measurements can be carried out continuously, the apparatus takes analyte which returns into the box after the analysis. The detection limit of the apparatus is 0.5 ppm for toluene, 100ppb for formaldehyde, 100ppb for total organic carbon and 5 ppm for CO2. At present, the apparatus is set so that it can measure one pollutant, CO2 and H2O. Our future goal is to measure more gases simultaneously. Humidity, temperature and air pressure are also monitored during the experiment.
4.3. Results and Conclusions from Modified CEN Test for the Characterization of Photocatalytic Efficiency of Air Purifiers
There are two charts for each purifier (see Figs. 5 and 6). The charts on the left show the plot of percent reduction in the degradation of toluene and the second one shows change in concentration of CO2, which takes place during this process. The measured data for each model are listed below: 12

Changes in gas concentration (toluene-left, CO2-right) during the testing of purifier Retap-model 1.

Changes in gas concentration (toluene-left, CO2-right) during the testing of purifier Retap-model 1.

Changes in gas concentration (toluene-left, CO2-right) during the testing of purifier Retap-model 2.

Changes in gas concentration (toluene-left, CO2-right) during the testing of purifier Retap-model 2.

Retap 1: 71ppm/89h (see chart), 0.8 ppm/h

Retap 2: 38ppm/25h (see chart), 1.5 ppm/h

Retap 3: 13ppm/81h, 0.16ppm/h (the decline stopped on the concentration 3.5ppm)


The measured data show that the constructed Retap prototypes have a very promising potential for microbial degradation of pollutants (chemical substances) from the atmosphere.