Volume 12, No. 6, December 2012, Pages 1116-1124 PDF(791 KB)
Development of a Novel Porous Membrane Denuder for SO2 Measurement
Lin Shou1, Alex Theodore1, Chang-Yu Wu1,4, Yu-Mei Hsu2, Brian Birky3
1 Department of Environmental Engineering Sciences, University of Florida, Florida 32611-6450, USA
2 Wood Buffalo Environmental Association, Alberta T9K 1Y1, Canada
3 Florida Industrial and Phosphate Research Institute, Florida 33830, USA
4 Department of Environmental Engineering, National Cheng-Kung University, Tainan 701, Taiwan
Conventional denuders made of glass or metal are too heavy and bulky to be used in personal sampling systems. In this study, a portable Porous Membrane Denuder (PMD) was developed for personal sampling. The PMD utilizes the porosity of the membrane material and a configuration of multiple parallel flow channels to reduce the size and weight of the device, while increasing the gas collection efficiency. Four types of PMDs (PMD I, II, III and IV) with increasing numbers of channels and smaller channel openings were constructed and tested. Using 10% sodium carbonate coating and a feed concentration of 1 ppm, PMD Ia’s collection efficiency for sulfur dioxide over 8 hours was higher than 99.9%. For a feed concentration of 10 ppm, the 5-hr time-weighted-average collection efficiency for sulfur dioxide was 73.1%, 82.8%, 90.9%, 97.2% for PMD Ib, II, III and IV, respectively, compared with 96.6% of the Glass Honeycomb Denuder (GHD), which has similar structure to PMD IV. However, the weight of PMD IV is only one-tenth of that of the GHD. It is clear that with a similar physical structure, PMDs have similar capacities to traditional Glass Honeycomb Denuders, yet are much lighter and less expensive. This study demonstrates the great potential of this new type of denuder for many applications in the field of environmental and industrial hygiene monitoring. Particle loss fractions of the four types of PMDs in the size range of 1 to 10 μm were also measured and were 2.9%, 5.2%, 5.7% and 7.3%, respectively.
Porous membrane; Denuder; Sulfur dioxide; Diffusion; Collection efficiency.