Design and performance evaluation of a photocatalytic reactor for indoor air disinfection

Abstract

Since COVID-19 pandemic, indoor air quality control has become a priority, and the development of air purification devices effective for disinfecting airborne viruses and bacteria is of outmost relevance. In this work, a photocatalytic device for the removal of airborne microorganisms is presented. It is an annular reactor filled with TiO 2-coated glass rings and irradiated internally and externally by UV-A lamps. B. subtilis spores and vegetative cells have been employed as model biological pollutants. Three types of assays with aerosolized bacterial suspensions were performed to evaluate distinct purification processes: filtration, photocatalytic inactivation in the air phase, and photocatalytic inactivation over the TiO 2-coated rings. The radiation distribution inside the reactor was analysed by performing Monte Carlo simulations of photon absorption in the photocatalytic bed. Complete removal of a high load of microorganisms in the air stream could be achieved in 1 h. Nevertheless, inactivation of retained bacteria in the reactor bed required longer irradiation periods: after 8 h under internal and external irradiation, the initial concentration of retained spores and vegetative cells was reduced by 68% and 99%, respectively. Efficiency parameters were also calculated to evaluate the influence of the irradiation conditions on the photocatalytic inactivation of bacteria attached at the coated rings.

Green aspects of photocatalysts during corona pandemic: a promising role for the deactivation of COVID-19 virus

“…), metal-free photocatalysts (graphene, GO, rGO, and g-C 3 N 4 ), and 2D semiconductor materials, they are being employed as coatings for masks and air lters, paints, and disinfectants to prevent community spread of the deadly virus. [148][149][150] Additionally, owing to the photothermal effect of MXenes and targeted drug-carrier ability of MOFs/COFs, it is highly anticipated that these advanced materials can be smartly and intensively explored for the therapeutic treatment of COVID-19 disease in the future.…”

“…There are several measures including the use of PPE kits, social distancing, proper sanitization, surgical and medical (single use) masks that are suggested for COVID-19 control, and prevention for self-protection. [147][148][149][150] Nevertheless, massive use of these preventive measures encounters signicant challenges in the recycling and sterilizing of various utensils and cloths. The advantages of photocatalytic viral disinfection over homogeneous-phase advanced oxidation processes are well documented.…”

“…Moreover, as-fabricated lters further can also be used for purication or as conditioners. 149,150 Thus, these above-mentioned sustainable, reusable, and eco-friendly methods could be a great alternative solution in dealing with the ongoing COVID-19 contagion.…”

Mitigation of Air Pollutants by UV-A Photocatalysis in Livestock and Poultry Farming: A Mini-Review

“…The bactericidal effect from UV photocatalysis may attract attention as an application to prevent this loss in the future. For example, UV-A photocatalysis has shown bactericidal effects for bioaerosols [66,67], surfaces [68] and liquids [69,70].…”

Towards Scaling-up Photocatalytic Process for Multiphase Environmental Applications: A Review

“…Another reactor geometry for air treatment is tubular flow photoreactors enclosing lamps (Figure 7g,h) [126,127]; for enhanced mass transfer and surface-to-volume ratio, multi-walls based reactors have been constructed as shown in (Figure 7i) [128][129][130]. [83].…”