K731 rapport 06 324 photocatalyse

633 views

Published on

Published in: Education, Technology, Business
0 Comments
0 Likes
Statistics
Notes
  • Be the first to comment

  • Be the first to like this

No Downloads
Views
Total views
633
On SlideShare
0
From Embeds
0
Number of Embeds
1
Actions
Shares
0
Downloads
7
Comments
0
Likes
0
Embeds 0
No embeds

No notes for slide

K731 rapport 06 324 photocatalyse

  1. 1. Report n° 06/324 Degradation of a gas mixture at ppb level by a photocatalytic device The performance of the photocatalytic device was assessed in an one cubic meter box by following the removal of a gas mixture composed of acetaldehyde, propionaldehyde, heptane, toluene, o-xylene and styrene. Also, the device as able to removed more than 99,99 % of the starting odour level. This report should only be reproduced in its entirety Study for : Saint-Gobain Quartz S.A.S Attention of : Mr Molins Customer request nr : 00023858 Certech request nr: K371 Certech quotation nr : OP/06/104/CB Emission date : 14-07-06 Scientific Approval, Quality Approval, CERTECH asbl - CEntre de Ressources TEchnologiques en CHimie Rue Jules Bordet, Zone Industrielle C – B 7180 SENEFFE TVA BE 0470.677.454 ING 370-1128214-94 FORTIS 271-0204412-65 Tél : +32 (0)64 52 02 11 Fax : +32 (0)64 52 02 10 e-mail : info@certech.be
  2. 2. Degradation of a gas mixture at ppb level by a photocatalytic device 1. Study objectives. The aim of this study was to test a photocatalytic device (ref CERTECH 603Y002) received by Saint Gobain, for the degradation of a gas mixture at low concentration and the assessment of the odour removal. 2. Methodology The experiment was carried out in a 0,9 m³ box and the pollutants were analysed on line by means of GC-PID. The GC-PID is able to analyse gas concentration at ppb level without any pre- concentration. . Figure 1 : photocatalytic device in the test chamber It was proposed to work with the following mixture around 600 ppb for each compound : • acetaldehyde • propionaldehyde • n-heptane • toluene • styrene • o-xylene Pollutants were introduced in the test chamber by using a micro-syringe. Figure 2 shows the chromatogram of a GC-PID analysis of the mixture of acetaldehyde (peak 1), propionaldehyde (peak 2), heptane (peak 3), toluene (peak 4) , o-xylene (peak 5) and styrene (peak 6) CERTECH asbl page 2 of 9 06/1488 This report should only be reproduced in its entirety
  3. 3. Degradation of a gas mixture at ppb level by a photocatalytic device Figure 2 : chromatogram profile of a gas mixture Unfortunately, as shown in figure 3, there is an interference with acetaldehyde and an unknown peak in the blank. This interference had to be subtracted from the analysis. Figure 3 : chromatogram profile of a blank. CERTECH asbl page 3 of 10 06/324 This report should only be reproduced in its entirety
  4. 4. Degradation of a gas mixture at ppb level by a photocatalytic device Air samplings on Airtoxics tubes were performed at different time. Figure 4 : air sampling on Airtoxics tube. This sampling concentrated molecules on the Airtoxics tubes. The sample was analysed by thermal desorption and gas chromatography coupled with a mass spectrometer detector. This allowed us to detect some by-products that could be formed during the experiment. The pumping flow was 100 ml/min and the pumping time varied from 5 to 60 minutes. The evaluation of the odour removal was performed by sampling air at the start and at the end of the degradation test. These samples were analysed by dynamic olfactometry to quantify their odour concentration. Dynamic olfactometry was performed according to the standard EN13725 (results expressed in European odour unit per cubic meter) by using a panel of four pre-calibrated people. For this test, the concentration of the mixture was increased to have a strong starting odour. The temperature and the relative humidity on the lab was recorded by a Dostmann electronic P570 humidity/temperature probe. The temperature and the humidity profile are shown in graph 1. The temperature rose from 23 to 25 during the tests and the humidity varied between 45 and 55 %. CERTECH asbl page 4 of 10 06/324 This report should only be reproduced in its entirety
  5. 5. Degradation of a gas mixture at ppb level by a photocatalytic device 30 70 60 25 50 20 Temperature (°C) 40 RH (%) 15 30 10 20 5 10 0 0 8:24:00 9:36:00 10:48:00 12:00:00 13:12:00 14:24:00 15:36:00 time temperature (°C) RH % Graph 1 : temperature and humidity profiles CERTECH asbl page 5 of 10 06/324 This report should only be reproduced in its entirety
  6. 6. Degradation of a gas mixture at ppb level by a photocatalytic device 3. Results. The results of the first test is reported on graph 2 0.8 Device on 0.7 0.6 concentration (ppmv) 0.5 0.4 0.3 0.2 0.1 0 0 20 40 60 80 100 120 140 times (min) toluene styrene propionaldehyde o-xylene heptane acetaldehyde Graph 2 : mixture degradation profile. The device was switched on position 3 after 64 min. As shown in graph 2, all chemical are quite rapidly removed from the gas phase. Heptane is removed slower than the others. The chemical profile of the second test (at higher concentration) is shown at graph 3. The device was switched on position 3 after 44 min. Removal profiles are similar for the two tests. Styrene and o-xylene are quickly removed followed by propionaldehyde, acetaldehyde, toluene and finally, heptane. The propionaldehyde and acetaldehyde have similar profile, the delay observed for acetaldehyde is due to its higher starting concentration. Air sampling for the odour characterisation were taken before switching the device and after 150 min. A blank sample was also taken before introducing the mixture in the test chamber. Results are shown in table 1 CERTECH asbl page 6 of 10 06/324 This report should only be reproduced in its entirety
  7. 7. Degradation of a gas mixture at ppb level by a photocatalytic device 3 Odour air sampling, start Device on 2.5 concentration (ppmv) 2 1.5 1 0.5 Odour air sampling, end 0 0 20 40 60 80 100 120 140 160 time (min) toluene styrene propionaldehyde o-xylene heptane acetaldehyde Graph 3 : second test at higher concentration. Table 1 : Odour characterisation results Odour level (OUE/m³) Blank 23 Mixture level 6600 After test 17 % removal > 99,99 % The photocatalytic device is able to remove more than 99,99% of the odour. The odour level after the degradation test is similar to the blank. The graphs 4 and 5 show the chromatograms of the air sampling on Airtoxics sampler tubes. The Airtoxics sampler was used to trap lighter chemical that could be present in the air. No significant by-products are observed on the sampling as it can see in graph 6. Beside the mixture components, acetic acid is detected in the first test after 30 minutes and some unknown chemical are observed in the second test on the sample taken after 55 minutes. The “step” observed between 2 and 4 minutes on the chromatograms is due to the presence of water adsorbed on the Airtoxics. CERTECH asbl page 7 of 10 06/324 This report should only be reproduced in its entirety
  8. 8. Degradation of a gas mixture at ppb level by a photocatalytic device 60000000 60000000 o-xylene styrene 50000000 50000000 response (u.a) 40000000 30000000 40000000 20000000 propionaldehdye response (u.a) acetaldehdye 10000000 30000000 heptane 0 15 15.2 15.4 15.6 15.8 16 time (min) 20000000 toluene 10000000 0 0 5 10 15 20 25 30 35 40 45 time (min) Before test (sampling time 5 min) 30 min test (sampling time 10 min) 60 min (sampling time 10 min) Graph 4 : chromatogram of the air samples on Airtoxics tubes for the first test. 90000000 90000000 80000000 80000000 o-xylene heptane 70000000 response (u.a) 60000000 70000000 50000000 40000000 60000000 styrene 30000000 toluene 20000000 response (u.a.) 50000000 10000000 0 15 15.2 15.4 15.6 15.8 16 40000000 acetalehyde time (min) 30000000 propionaldehyde 20000000 10000000 0 0 5 10 15 20 25 30 35 40 45 time (min) Before test (sampling time (5 min) after 55 min (sampling time 20 min) after 150 min (sampling time 60 min) Graph 5: chromatogram of the air samples on Airtoxics tube for the second test. The estimation of the heptane, toluene, o-xylene and styrene concentration are reported on table 2. For this purpose, the PID value just before starting the device was used to estimate the concentration of the other samples. The results are reported on table 2. The PID value when the compound is detected is also indicated. CERTECH asbl page 8 of 10 06/324 This report should only be reproduced in its entirety
  9. 9. Degradation of a gas mixture at ppb level by a photocatalytic device Table 2 : Concentration estimation of heptane, toluene, styrene and o-xylene in the gas phase from the air sample on Airtoxics tube Cartouche/PID Cartouche Cartouche PID (ppmv) PID (ppmv) (ppmv) (ppmv) (ppmv) Test 1 0 min 30 min 60 min 30 min 60 min Heptane 0.59 0.0853 0.00142 0.03 nd Toluene 0.67 0.0089 0.00009 nd nd Styrene 0.676 0.0204 0.000492 nd nd o-xylene 0.478 0.0253 0.00144 nd nd Test 2 0 min 55min 150 min 55 min 150 min Heptane 2.07 0.056 0.000174 0.099 nd Toluene 1.91 0.0176 0.000038 nd nd Styrene 0.39 0.0084 0.000079 nd nd o-xylene 1.13 0.0222 0.000246 nd nd The concentration estimated of heptane, toluene, styrene and o-xylene from the air sampling indicates that detected by-product are well below the ppbv level. 18000000 16000000 14000000 12000000 heptane response (u.a.) 10000000 styrène/o-xylene 8000000 6000000 acetic acid toluene 4000000 unknow 2000000 0 0 5 10 15 20 25 30 35 time (min) test 1 after 30 min (sampling time 10 min) test 2 after 55 min (sampling time 20 min) Graph 6 : air sampling results of the first test after 30 min and the second test after 55 min. CERTECH asbl page 9 of 10 06/324 This report should only be reproduced in its entirety
  10. 10. Degradation of a gas mixture at ppb level by a photocatalytic device 4. Conclusions. The performance of the photocatalytic device was assessed in an one cubic meter box by following the removal of a gas mixture composed of acetaldehyde, propionaldehyde, heptane, toluene, o- xylene and styrene. Heptane needs more time than the other chemicals to be removed. The device is able to remove more than 99,99 % of the starting odour level. Some by products, acetic acid and unidentified chemicals, are produced at concentration well below the ppbv level. CERTECH asbl page 10 of 10 06/324 This report should only be reproduced in its entirety

×