Photocatalytic Degradation of Gaseous Formaldehyde Using TiO₂ Film

Abstract

The photocatalytic degradation of gaseous formaldehydesa major cause of sick building syndromeswas studied using a TiO 2 thin film. TiO 2 thin films have many unique photoinduced properties, for example, self-cleaning, antifouling, and anti-bacterial functions. UV illumination of the TiO 2 thin film placed in a gaseous formaldehyde/air environment resulted in the total mineralization of formaldehyde to CO 2 and H 2 O. We invoked a Langmuir-Hinshelwood kinetic model to analyze the dependence of reaction rates on the concentration of formaldehyde. In addition, the overall decomposition rate constant for formaldehyde was comparable to that of acetaldehyde (a standard test reactant) for initial concentrations of up to 1000 ppmv. However, the apparent adsorption constant K app of formaldehyde onto TiO 2 was ca. 2.5 times larger than that of acetaldehyde. Thus in the low concentration regime, the reactivity of formaldehyde appeared to be greater than that of acetaldehyde. In like manner, a dark adsorption experiment also showed the high adsorption capacity of TiO 2 for formaldehyde. Therefore, we conclude that TiO 2 serves as both a good adsorbent and a photocatalyst for the elimination of gaseous formaldehyde.

Catalytic oxidation of formaldehyde over manganese oxides with different crystal structures

“…4 Hence, effective abatement of indoor air HCHO is urgently needed in order to improve air quality and reduce the public health risk. Several approaches for HCHO removal have been studied during decades of research, including photo-catalytic oxidation, 5,6 plasma decomposition with catalyst, 7 adsorption 8 and catalytic oxidation. [9][10][11] However, photo-catalytic oxidation needs light containing ultraviolet wavelengths to excite the catalyst, and may lead to the formation of harmful by-products.…”

Preparation of TiO2-Coated Polyester Fiber Filter by Spray-Coating and Its Photocatalytic Degradation of Gaseous Formaldehyde

“…Many previous studies focused on the degradation mechanism and limiting factors, such as relative humidity, initial pollutant concentration, light intensity, etc. (Peral and Ollis, 1992;Obee and Brown, 1995;Obee, 1996;Noguchi et al, 1998). In the past decade, more concerns have been raised on the effectiveness of photocatalyst immobilization for its potential on large scale application (Paschoalino et al, 2006;Žabová and Dvořák, 2009;Paz, 2010).…”

Galvanic Corrosion Characteristics of Aluminium Alloy with Group II Metal

“…and the corresponding parameters derived from the analysis are tabulated in table-5. The impedance spectra of all the anodes studied in the present work have centre lies under the real axis, which is the characteristic behaviour of Al-Zn alloys undergoing uniform galvanic dissolution [24] . The high frequency plot associated with the charge transfer process and the low frequency plot corresponds to mass transfer process.…”