photoreactors devoted to the removal of VOCs, since it easily
takes into account the complex interactions between the
flow field, the light activation, and the reactions kinetics
(1, 17 21). CFDmight be helpful for bioaerosol remediation
too, because working with bioaerosols remains time- and
material-consuming. Although concepts like the adsorption
or the diffusion of chemicals cannot be easily transferred to
the microbial inactivation, this tool could help in designing
efficient biocidal reactors by enhancing the impact prob-
ability of the microorganisms on the surface.
Experimental Section
Photocatalytic Pilots for AMO-Contaminated Air Treat-
ment. The micropilot used for performing the single-pass
UV-A photocatalytic treatment of contaminated air has been
previously detailed (scheme as SI S2), aswell as the procedure
for preparing and aerosolizing L. pneumophila aqueous
suspension for generating a reproducible contaminated air
flow, and that for recovering and numerating bacteria from
the outlet stream(14). The single-pass tests were performed
ata5m3
/h air flow in an 70 mm wide and 300 mm long
annular photoreactor with a central 19 mm diameter 8W
UV-A actinic lamp (Philips, actinic BL, TL8). In this config-
uration, the reactor worked with an annular space of 25.5
mm. The TiO2 coating was performed by evaporating to
dryness aqueous slurry of the TiO2 and the coated reactor
was dried at 110 °Cfor1hin air. Details on the reactor and
on the coating method could be found in ref 22.
Recirculation testswere performedwith a tangential flow
reactor at a 140 m3
/h air flow in a 0.8 m3
glovebox adapted
for AMOs and used as reaction chamber, targeting L.
pneumophila, T2 naked virus, and B. atrophaeus spore. This
reactor has been commercialized by the Biowind company
(France) under the DPA label, schematized in Figure 1 with
the lighting coming from the top of the fan (14). TiO2 was
coated by dipping using an aqueous suspension of TiO2 and
further drying at ambient temperature. This photoreactor
has an inner volume of 1.2 L with a photoactive surface of
1040 cm2
and a TiO2 coating density of 1mg/cm2
. Details on
the reactor and on the coatingmethod could be found in ref
14. In both cases, TiO2 P25 (Degussa - Evonik) was used.
Targeted AMOs. Extensive details on the preparation of
the bacteria, virus and spore suspensions used for aero-
solization are reported as SI S3. L. pneumophila of 1 2 µm
size is a well-known AMO, well adapted for bioaerosol tests.
The contaminated bioaerosol was obtained by aerosolizing
a 5 mL aliquot of a 1.0 × 107
L. pneumophila (strain GS3.11)
bacteria/mL aqueous suspension into the reaction chamber
as droplets in a high flow rate air stream using a peristaltic
pump (6.3 × 107
microorganisms per m3
of air).
50 nmmean size T2 naked bacteriophage viruses are used
asmodels for airborne viruses. The contaminated bioaerosol
was obtained by aerosolizinga5mL aliquot of a 1.51 × 108
T2 bacteriophages/mL suspension into the reaction chamber
as droplets in a high flow rate air stream using a peristaltic
pump (9.4 × 108
microorganisms per m3
of air).
Bacterial endospores (≈1 µm) are considered to be the
most resistant living formand are produced byGram-positive
bacteria to survive extreme situations. Bacillus atrophaeus
spores, former labeled as B. subtilis, were used, since they
are used in dry-heat disinfection norms (EN866-2), andwere
already positively used as a surrogate of environmentally
resistant pathogenic microorganisms like anthrax (B. an-
thracis spores). The contaminated bioaerosol was obtained 生物性气胶的光催化处理英文文献和中文翻译(3):http://www.751com.cn/fanyi/lunwen_9162.html