Kuo-Pin Yu1, Whei-May Grace Lee 2, Guan-Yi Lin2

  • 1 Institute of Environmental and Occupational Health Sciences, National Yang-Ming University, Taipei 11221, Taiwan
  • 2 Graduate Institute of Environmental Engineering, National Taiwan University, 71 Chou-Shan Road, Taipei, Taiwan

Received: September 10, 2014
Revised: December 16, 2014
Accepted: January 26, 2015
Download Citation: ||https://doi.org/10.4209/aaqr.2014.09.0202 

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Cite this article:
Yu, K.P., Lee, W.M.G. and Lin, G.Y. (2015). Removal of Low-Concentration Formaldehyde by a Fiber Optic Illuminated Honeycomb Monolith Photocatalytic Reactor. Aerosol Air Qual. Res. 15: 1008-1016. https://doi.org/10.4209/aaqr.2014.09.0202


HIGHLIGHTS

  • Fiber-Illuminated honeycomb Photocatalytic Reactor for indoor formaldehyde removal.
  • Optical fiber and honeycomb work together enhanced the formaldehyde photodegradation.
  • The formaldehyde removal efficiency can be as high as 95%.

 

ABSTRACT


In this study, we systematically investigated the removal of low-concentration formaldehyde by the fiber optic illuminated honeycomb monolith photocatalytic reactor and the influential factors including formaldehyde concentration (0.8–2.0 ppm), relative humidity (RH30–70%), and air flow rate (800–1600 mL/min). The experimental results of various formaldehyde concentrations indicate the kinetic fits the Langmuir–Hinshelwood model, and the rate constants (k) under RH30%, 50% and 70% are 1.09, 1.37, and 1.68 μ-mole/m2/s, respectively. The Langmuir adsorption constants of formaldehyde under RH30%, 50% and 70% are 4.10 × 10–3, 2.98 × 10–3 and 2.14 × 10–3 ppm–1, respectively. Increasing relative humidity has a positive effect on the rate constant of photocatalytic oxidation k, which is relevant to the enhancement effect of relative humidity on the formation of hydroxyl radicals. On the other hand, the formaldehyde conversion and Langmuir adsorption constant of formaldehyde decrease with the increase of relative humidity, which may be associated with the competition between formaldehyde and water molecules for the adsorption sites on the surface of TiO2 photocatalyst. Because the air flow rate was low (≤ 1600 mL/min), the gas retention time (≥ 7.7 sec) was long enough for the reactor to achieve a high formaldehyde conversion (≥ 92%), but the breakthrough of formaldehyde might occur when air flow rate > 4200 mL/min.


Keywords: Indoor; Formaldehyde; Influential factors


Impact Factor: 2.735

5-Year Impact Factor: 2.827


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