Department of Environmental Science, Faculty of Science and Technology, Thammasat University, Thailand.
Indoor Air. 2010 Jun;20(3):246-54. doi: 10.1111/j.1600-0668.2010.00651.x.
This study assessed the application of photocatalytic oxidation (PCO) to the high efficiency particulate air (HEPA) filter for disinfection of airborne microorganisms. Experiments were conducted at two TiO2 loadings (1870 +/- 169 and 3140 +/- 67 mg/m(2)) on the HEPA filter irradiated with UV-A at the intensity of 0.85 +/- 0.18 or 4.85 +/- 0.09 mW/cm(2) under two relative humidity conditions (45 +/- 5% and 75 +/- 5%). Inactivation and penetration of four microorganisms were tested, including Aspergillus niger, Penicillium citrinum, Staphylococcus epidermidis, and Bacillus subtilis. It was found that microorganisms retained on a photocatalytic filter were inactivated around 60-80% and even 100% for S. epidermidis when the PCO reactions occurred. Lower penetration was also found from the photocatalytic filter for all airborne microorganisms. High humidity decreased photocatalysis efficacy. Increasing TiO2 loading or irradiance intensity did not substantially affect its disinfection capability.
The high efficiency particulate air filter is used widely to remove particulates and microorganisms from the air stream. However, the filter may become a source of microbes if those retained microorganisms proliferate and re-entrain back into the filtered air. This study demonstrates that such a problem can be handled effectively by using photocatalytic reactions to inactivate those confined microorganisms. A 60-100% microbe reduction can be achieved for a wide variety of microorganisms to provide better indoor air quality for hospitals, offices, and domestic applications.
本研究评估了光催化氧化（PCO）在高效空气过滤器（HEPA）上的应用，以对空气中的微生物进行消毒。实验在两种 TiO2 负载量（1870 ± 169 和 3140 ± 67 mg/m2）下进行，HEPA 过滤器在相对湿度为 45 ± 5%和 75 ± 5%的两种条件下，用强度为 0.85 ± 0.18 或 4.85 ± 0.09 mW/cm2 的 UV-A 进行照射。测试了四种微生物（黑曲霉、桔青霉、表皮葡萄球菌和枯草芽孢杆菌）的失活和穿透情况。结果发现，当 PCO 反应发生时，附着在光催化过滤器上的微生物的失活率约为 60-80%，甚至对表皮葡萄球菌达到 100%。对于所有空气中的微生物，从光催化过滤器中的穿透率也较低。高湿度会降低光催化效率。增加 TiO2 负载量或辐照度强度不会显著影响其消毒能力。
高效空气过滤器广泛用于从气流中去除颗粒物和微生物。然而，如果被截留的微生物繁殖并重新进入过滤后的空气中，过滤器可能成为微生物的来源。本研究表明，可以通过使用光催化反应来有效处理这种问题，从而使被截留的微生物失活。对于各种微生物，可以实现 60-100%的微生物减少，从而为医院、办公室和家庭应用提供更好的室内空气质量。
