The effect of anatase and rutile crystallites isolated from titania P25 photocatalyst on growth of selected mould fungi

Abstract

Antifungal properties of anatase and rutile crystallites isolated from commercial titania P25 photocatalyst were investigated by mycelium growth in the dark and under indoor light. Investigated fungi, i.e., Pseudallescheria boydii, Scedosporium apiospermum, Pseudallescheria ellipsoidea, Scedosporium aurantiacum, Aspergillus versicolor, Aspergillus flavus, Stachybotrys chartarum, Penicillium chrysogenum, Aspergillus melleus, were isolated from air and from moisture condensed on walls. Anatase and rutile were isolated from homogenized P25 (homo-P25) by chemical dissolution, and then purified by washing and thermal treatment. For comparison, homo-P25 was also thermally treated at 200 °C and 500 °C. Titania samples were characterized by X-ray diffractometry (XRD), X-ray photoelectron spectroscopy (XPS), diffuse reflectance spectroscopy (DRS) and scanning transmission electron microscopy (STEM). It was found that properties of titania, i.e., band-gap energy, impurities adsorbed on the surface, nanoparticle aggregation, and kind of fungal structure, highly influenced resultant antifungal activities. It is proposed that some fungi could uptake necessary water and nutrient from titania surface. It was also found that even when differences in mycelium growth were not significant, the sporulation and mycotoxin generation were highly inhibited by light and presence of titania.

Morphology- and Crystalline Composition-Governed Activity of Titania-Based Photocatalysts: Overview and Perspective

“…Titania P25, known also as Degussa P25, Evonik P25, and Aeroxide P25, is probably the most famous mixed-phase titania, due to its extremely high photocatalytic activity in various photocatalytic reactions. For example, P25 was used for the decomposition of organic [44][45][46][47][48][49][50] and inorganic [51] compounds present in water and wastewater, the degradation of gas-phase pollutants [52][53][54][55][56], the purification of indoor environments (e.g., allergens' removal [57]), inactivation of microorganisms [58][59][60][61][62][63], self-cleaning surfaces [64][65][66] and solar energy conversion [67]. The number of cited papers using "P25"and "photocatalysis" as keywords has exceeded 10,000 per year, as shown in Figure 2.…”

Gas‐phase removal of indoor volatile organic compounds and airborne microorganisms over mono‐ and bimetal‐modified (Pt, Cu, Ag) titanium(IV) oxide nanocomposites

“…18 Commercial application of photocatalysis is associated with the costs of photocatalytic process, thus it is essential to look for new environmentally friendly light sources. 23 In comparison with Xe, Hg or fluorescent lamps, LEDs are characterized by a significantly longer work time and greater efficiency.…”

“…22 Penicillium chrysogenum was selected as a airborne pathogenic fungi present in the indoor environment, especially in a damp or water-damaged building with a highly negative impact on human health. 23…”

Silver- and copper-modified decahedral anatase titania particles as visible light-responsive plasmonic photocatalyst

“…45 For example, a slight change in morphology of trilayered gold (core)/silver/titania nanorods resulted in a change of the mechanism from electron transfer to energy transfer (with an increase in titania thickness). 44 It should also be pointed out that a large majority of the studies has been performed for commercial support of noble metals, often on titania P25 (nonuniform mixture of anatase, rutile, and amorphous phases), 46,47 consisting of various impurities, irregular morphology, and being highly heterogeneous, where possible participation of various components and defects in resultant overall photocatalytic performance cannot be neglected. Therefore, in this study facetted anatase titania particles [decahedral anatase particles (DAPs) with eight (101) facets and two (001) facets] of well-controlled morphology and thus high photocatalytic activity were used as a support for nanoparticles of noble metals.…”