The home appliance company decides to perform additional design work on the proposed air purifier.

(a) The \(\mathrm{PtTiO}_{2}\) coated HEPA filter is expected to be easily clogged by particulates in the air. It is decided that a prefilter is needed. Redesign the configuration in Figure \(5.8 \mathrm{~b}\) to include a HEPA prefilter that can be easily replaced.

(b) To avoid the use of a prefilter, a new configuration as shown in the following graphic is proposed. \(\mathrm{PtTiO}_{2}\) nanoparticles are coated on the inner surface of a metal cylinder. A UV lamp is placed along the central axis of the cylinder. Compare this design with that in Figure 5.8b under the same UV light intensity.

(c) VOCs are composed of different compounds. It is proposed that, in addition to toluene, ethanol be used as a reference compound for quantifying product performance. Assume that the mechanism of ethanol decomposition on UV-excited \(\mathrm{PtTiO}_{2}\) is the same for toluene. The following regressed parameters were obtained through experiments conducted under a light intensity of \(2.2 \mathrm{~mW} / \mathrm{cm}^{2}\), ethanol concentration of \(10-100 \mathrm{mg} / \mathrm{m}^{3}\), catalyst thickness of \(38.5 \mu \mathrm{m}\), and a relative humidity range of \(17-82 \%\). Calculate the amount of catalyst required to reduce ethanol concentration from \(100 \mathrm{mg} / \mathrm{m}^{3}\) to \(50 \mathrm{mg} / \mathrm{m}^{3}\) in the same room within two hours.

Data From Figure 5.8:-

Transcribed Image Text:

Metal Cylinder PiTiO2 Coating UV Lamp Inlet Outlet