Photocatalytic Reactors for Air Treatment

The removal of airborne contaminants is an area of promising applications for photocatalysis. The challenges to be faced involve the treatment of relatively large gas flows in devices with low pressure-drops, good photocatalyst irradiation and efficient reactant species-photocatalyst contacting (Dibble and Raupp, 1992). In the near future photocatalytic reactors, incorporating the use of solar energy, are also anticipated to be developed. 

It is also expected that these novel designs, as in the case of water treatment, could be engineered to efficiently achieve total pollutant mineralization (Serrano and de Lasa, 1997). 

To achieve these goals, photocatalytic reactors for air treatment require careful design and the selection of a number of reactor parameters such as 

Several laboratory photocatalytic reactor configurations have been described in recent years  

These designs were tested considering as performance qualifiers the levels of photoconversion of various classes of pollutants at different concentrations, temperatures, relative humidity, pressures, space-times and irradiation times. 

---

Three photocatalytic reactors for water treatment and one for air treatment have been conceptualized ... 

This chapter tries to analyze the use of titanium dioxide for photocatalytic air treatment. For this, the various types of applications will be discussed, as well as the mechanisms and reaction kinetics of some of the most popular model contaminants. Care will be given to characterize the large variety of photocatalytic reactors in use for air treatment. 

This chapter tried to summarize a few of the aspects related to photocatalytic air treatment. Particular efforts were made to identify the large variety of photocatalytic reactors for indoor air treatment and to point toward the prospects and obstacles in utilizing titanium dioxide for this purpose. 

De Lasa, H., Novel photocatalytic reactors for water and air treatment, in Photocatalytic Reaction Engineering, Springer Science + Business Media, New York 2005. 

Regarding air treatment, to our knowledge, large-scale photocatalytic reactors based on fluidized beds are not used Ti02 is always supported. For water treatment, the system designed by Purifies Environment Tech-... 

Photocatalysis, i.e., using semiconductor particles under band gap irradiation as little micro reactors for the simultaneous reduction and oxidation of different redox systems, has been intensively studied during the last 25 years since the pioneering work of Carey et al [1]. The main focus of these studies seems to be the investigation of the principal applicability of photocatalytic systems for the efficient treatment of water and air streams polluted with toxic substances. Several review articles on this topic have recently been published [2]. In some cases, pilot-scale or even commercially available reactors have already been constructed, especially when titanium dioxide is used as the photocatalyst [3]. 

Photocatalytic reactors with immobilized Ti02 have suitable configurations for both water and air treatment. These include reactors in which the catalyst is fixed (anchored) on a support via physical surface forces or chemical bonds. 

Sczechowski, J. G., Koval, C. A., and Noble, R. D., 1993, Improved photoefficiencies for Ti02 photocatalytic reactors through the use of controlled periodic illumination in Photocatalytic purification and treatment of water and air, Ollis, D., Al-Ekabi, H., eds., Elsevier, New York, pp. 645-649. 

---