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The outbreak of the COVID 19 pandemic confirmed the importance of personal protective equipment including the respiratory face masks as barriers to pathogens. Taking into account that face masks are mainly composed of polypropylene (PP) non-woven materials this study explores the possibility of in situ biosynthesis of silver-based nanoparticles as an antimicrobial agent on PP material. A pomegranate peel extract was used as a “green” agent for synthesis and stabilization of nanoparticles. Hydrophobicity of PP fibers was overcome by modification with corona discharge at atmospheric pressure. In order to improve the binding of silver ions, corona modified PP material was impregnated with biopolymer chitosan in the presence of crosslinker 1,2,3,4-butanetetracarboxylic acid. SEM analysis revealed the presence of spherical Ag-based nanoparticles on the fiber surface with an average size of approximately 69 nm. The higher the concentration of the precursor salt, the higher the silver content after the reduction. Larger amounts of Ag-based nanoparticles provided stronger antimicrobial activity against bacteria Escherichia coli and Staphylococcus aureus, and yeast Candida albicans.

Commercial P25 TiO2 nanoparticles are widely exploited as an efficient photocatalyst. In the textile domain, these nanoparticles are used for the production of self-cleaning, highly UV protective textiles, with an antimicrobial activity. The disposed textile products may end up in a landfill where they are subjected to the biodegradation process. Considering the importance of the later, this study discusses the biodegradation behaviour of cotton fabric impregnated with commercial P25 TiO2 nanoparticles. Photocatalytic activity of TiO2 nanoparticles immobilized on cotton fabric was proved by the photodegradation of dyes C.I. Acid Orange 7 and methylene blue in aqueous solution. Biodegradation of fabrics was assessed by soil burial test in periods of 3, 9 and 18 days. Chemical and morphological changes induced by biodegradation were analyzed by FTIR, SEM and EDS. A colour of the samples gradually changed from white to yellow/brown due to rotting. SEM analysis revealed a severe destruction of the control and impregnated cotton fibres after 18 days of soil burial which was in line with visual appearance of completely damaged fabrics. The results confirmed that biodegradation behaviour of both the control and impregnated sample was equivalent, indicating that P25 TiO2 nanoparticles did not inhibit the biodegradation process of cellulose. [Projects of the Serbian Ministry of Education, Science and Technological Development, Grant no. 172056 and Grant no. 45020]

This study discusses the possibility of immobilization of colloidal TiO2 nanoparticles (NPs) onto poly(ε-caprolactone) (PCL) beads and foams that could be utilized for the removal of textile dyes from water by photodegradation. PCL foams were fabricated by environmentally friendly treatment of PCL beads in supercritical carbon dioxide. PCL beads and foams loaded with colloidal TiO2 NPs were used as photocatalysts for the removal of the textile dyes C.I. Acid Orange 7 and C.I. Basic Yellow 28 from aqueous solutions (10 mg L-1) under illumination that simulated sunlight. Unlike the PCL beads, the PCL foams provided complete discoloration of the dye solution within 24 h of illumination. The PCL foams also exhibited excellent floatability that was maintained for more than four weeks. Additionally, their photocatalytic activity was preserved within three repeated photodegradation cycles, indicating that the floating photocatalyst provided superior photocatalytic activity compared to the non-floating PCL beads. [Project of the Serbian Ministry of Education, Science and Technological Development, Grant no. 172056 and Grant no. 45020]