Using circular economy principles to recycle materials in guiding the design of a wet scrubber-reactor for indoor air disinfection from coronavirus and other pathogens

Abstract

An arduous need exists to discover rapid solutions to avoid the accelerated spread of coronavirus especially through the indoor environments like offices, hospitals, and airports. One such measure could be to disinfect the air, especially in indoor environments. The goal of this work is to propose a novel design of a wet scrubber-reactor to deactivate airborne microbes using circular economy principles. Based on Fenton's reaction mechanism, the system proposed here will deactivate airborne microbes (bioaerosols) such as SARS-CoV-2. The proposed design relies on using a highly porous clay-glass open-cell structure as an easily reproducible and cheap material. The principle behind this technique is an in-situ decomposition of hydrogen peroxide into highly reactive oxygen species and free radicals. The high porosity of a tailored ceramic structure provides a high contact area between atomized oxygen, free radicals and supplied polluted air. The design is shown to comply with the needs of achieving sustainable development goals.

Keywords: Air disinfection; COVID-19; Coronavirus; Porous ceramics; Preparedness; Scrubber-reactor.

Graphical abstract

Fig. 1

Typical wet type gas scrubber (a) design and (b) typical materials and shape designs used in construction of a packed column (Seader et al., 2011).

Fig. 2

The dependence of the highly porous alumina ceramic foam microstructures and pore size distributions on the applied rotational speed during direct foaming process: (a) 400 RPM (b) 700 RPM and (c) 1100 RPM (Kroll et al., 2014).

Fig. 3

Foamed clay ceramic samples after sintering at 950 °C: (a) WG0-950 (without glass); (b) WG10-950 (with glass) – general view of the sample and; (c) WG10-950 optical microscopy image (30x magnification).

Fig. 4

SEM images of fractured foamed clay ceramic sample WG5-950: (a) general pore structure (100x magnification) and; (b) structure of the pore wall (1500x magnification) (Shishkin et al., 2020a).

Fig. 5

The optical microscopy images of glass containing foamed clay ceramic materials cross section: (a) WG5-800 °C; (b) WG5-950 °C.

Fig. 6

Influence of the glass-cullet loading (5, 7 and 10 wt. %) and firing temperature on the highly porous clay ceramic surface area (acquired using ${\text{N}}_2$ BET).

Fig. 7

Influence of the glass-cullet loading (5,7 and 10 wt. %) and firing temperature on the compression strength and total porosity. MC loading is indicated in the legend. The thermal sintering temperatures are indicated in ${}^{\circ }$C (Shishkin et al., 2020a).

Fig. 8

Principle scheme of the air filtration system: (a) filter unit scheme consisting of 1 — reservoir for H₂O₂ supply, 2 — ceramic filter, 3 — reservoir with the opening for collection and transfer of the remaining H₂O₂, 4 — bypass for pressure alignment, P1 and P2 — air pressure before and after ceramic filter; and filtering setups with H₂O₂ (b) “direct flow” and (c) “continuous counterflow” modes.

Fig. 9

The contaminated gas motion in porous structure (a) acceleration and collisions of particles during passing narrow openings of interconnected pores (b) causing increased number of collisions and (c) destructive reactions between contaminants and active radicals (HO•, $O_2$•${}^{-}$ are hydroxyl and superoxide radicals described in Eq. (1) to (4)).