Cotton Terry Textiles with Photo- and Bio-Activity in a Model Study and Real Conditions

Abstract

The aim of the study was to assess the photocatalytic (decompose staining particles, K/S values, the color differences, CIE L*a*b* color) and antimicrobial properties of textiles modified with TiO2 and ZnO nanoparticles (NPs) confirmed by X-ray diffraction, dynamic light scattering, SEM-EDX) in visible light conditions. The antimicrobial effectiveness of modified textiles under model conditions has been reported against 5 microorganisms: Staphylococcus aureus, Escherichia coli, Bacillus subtilis, Candida albicans, Aspergillus niger (AATCC Test Method 100-2004). In real conditions in bathrooms, significant biostatic activity was shown on the surface of the modified towels. The number of microorganisms decreased by 1–5 log to the level of 0–5 CFU/cm2 in the case of bacteria: Enterobacteriaceae, Enterococcus, the coli group and E. coli, Pseudomonas. Statistically significant reduction of the total number of bacteria and fungi (by 1 log), and the concentration of gases (NO2, CO2, CO) in the air of bathrooms was determined. The removal or reduction of volatile organic compounds (VOCs) concentration (SPME-GC-MS analysis) in the air above the modified towels has also been determined. It was found that the lighting type (natural, artificial), time (1.5 and 7 h/day), air humidity (RH = 36–67%) and light intensity (81–167 lux) are important for the efficiency of photocatalysis. Textile materials modified with TiO2 and ZnO NPs can be used as self-cleaning towels. They can also help purify air from microorganisms, VOCs and undesirable gases.

Long-Lasting Photocatalytic and Antimicrobial Activity of Cotton Towels Modified with TiO2 and ZnO Nanoparticles

“…In earlier research in the photocatalytically modified textiles model conditions, low and medium antimicrobial activity (A = 0.40-1.62) was observed towards the tested microorganisms: E. coli, S. aureus., B. subtilis, C. albicans, and A. niger [33]. In the present study, for the same microorganisms, higher antimicrobial activity was observed, mainly medium and high (A = 1.3-8.0) with the exception of low biostatic effect under conditions of lower light intensity 400 µW/cm 2 for B. subtilis, A. niger, and C. albicans (A = 0.46-0.96).…”

“…Cotton terry towels were surface-modified using commercial dispersions of ZnO and TiO 2 NPs using the padding-squeezing method. The crystal structure of NPs in dispersion are as follows: ZnO zincite crystal structure and TiO 2 rutile crystal structure, as were indicated in our earlier studies [33]. Rutile form is a stable phase of TiO 2 [34], and zincite form of ZnO is stable in a neutral medium at temperatures up to 1100 • C [35].…”

“…There are randomly distributed NPs and several larger particles on the surface of cotton terry textiles after 15 and 30 washings. Unfortunately, the magnification/resolution of the SEM microscope did not allow us to clearly show the nanoparticles as stated by the DLS analysis in our previous manuscript [33].…”

“…Earlier authors' studies showed that the tested materials modified with TiO 2 /ZnO nanoparticles in real conditions in bathrooms (lighting time 1.5 and 7 h/day, air humidity RH = 36-67%, light intensity, 81-167 lux) showed biostatic activity, and the number of microorganisms decreased by 1-5 log to the level of 0-5 CFU/cm 2 [33]. The present study in the conditions of supporting natural lighting with a light bulb (lighting time 12 h/day, air humidity RH = 39%, UVA/B radiation intensity 1400 µW/cm 2 ) showed an increase in antimicrobial activity, and the number of microorganisms decreased by 5-8 log to the level of 0 CFU/cm 2 .…”

“…In the previous studies [33], the authors assessed the photocatalytic and biological activity of 100% cotton terry towels modified with TiO 2 N-doped nanoparticles and ZnO nanoparticles under model and real conditions. The material obtained was characterised by significant biostatic activity on the surface, where the number of microorganisms (Enterobacteriaceae, Enterococcus, coli and E. coli group, as well as Pseudomonas) has decreased.…”