Vliv aditivace tenkých vrstev na bázi SiO2/TiO2 nanočásticemi na jejich fototokatalytickou a antimikrobiální účinnost
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Diplomová práce se zabývá vlivem přídavku nanočástic na fotokatalytické a antibakteriální účinnost SiO2/TiO2 suspenze Balclean. Pro aditivace byly zvoleny nanočástice Ag, ZnO a CuO, které byly syntetizovány v laboratorních podmínkách. Při syntéze nanočástic byl kladen důraz především na jednoduchost a efektivitu použitých metod, konrétně metoda chemické redukce pro Ag a metoda precipitace pro ZnO a CuO. U připravených nanočástic byla charakterizována jejich morfologie a velikost pomocí rastrovací elektronové mikroskopie doplněné o energiově disperzní analýzu. Průměrná velikost částic Ag se pohybovala okolo 220 nm, zatímco průměry částic ZnO a CuO byly okolo 70 nm. Připravené částice byly přidány do Balcleanu v koncentraci 1 hm. %. Antimikrobiální aktivita byla hodnocena dle normy ISO 27447; 2009, jako modelový organismus byla použita bakterie E. Coli. Přídavek částic ve všech případech vedl k výraznému nárůstu antibakteriální aktivity, což se projevilo u vzorků exponovaných UV záření i u vzorků, které byly ponechány ve tmě. Fotokatalytická účinnost byla hodnocena pomocí rozkladů NOx dle normy ISO 22197-1; 2007 a pomocí rozkladu methylenové modři dle normy ISO 10678; 2010. Zde se projevil nárůst fotokatalytické účinnosti v případě přídavku ZnO, zatímco u vzorků s přídavkem Ag, respektive CuO došlo k poklesu fotokatalytické aktivity. Tento pokles byl pravděpodobně zapříčiněn příliš velkou koncentrací přidaných částic, v případě stříbra se pravděpodobně negativně projevil velký průměr částic zapříčiněný metodikou přípravy. Další studium by mělo být zaměřeno na optimalizaci tvaru, velikosti a množství aditivovaných nanočástic.
The diploma thesis deals with efficiency of nanoparticles-additivation on photocatalytic and antibacterial activity of SiO2 / TiO2 suspension Balclean. Ag, ZnO and CuO nanoparticles were elected for additivation and synthesized under laboratory conditions. In the synthesis of nanoparticles, emphasis was placed on the simplicity and efficiency of the used methods, such as the chemical reduction method for Ag and the precipitation method for ZnO and CuO. Characterization of morphology and size using scanning electron microscopy was performed for prepared nanoparticles and it was further complemented with energy dispersion analysis. The average size of Ag particles was about 220 nm, whereas the diameters of ZnO and CuO particles were about 70 nm. The prepared particles were added to Balclean with the concentration of 1 wt%. Antimicrobial activity was assessed according to ISO 27447; 2009, E. Coli was used as a model organism. The addition of particles in all cases led to in a significant increase in antibacterial activity, which was observed on both UV exposed sample and sample kept in the dark. Photocatalytic efficiency was assessed by NOx degradation according to ISO 22197-1; 2007 and by the degradation of methylene blue according to ISO 10678; 2010. An increase in photocatalytic efficiency in case of additivation of ZnO was observed, whereas photocatalytic activity decreased in samples with addition of Ag (respectively CuO). This decrease was probably caused by too high concentration of added particles, in the case of silver, the large particle diameter probably had a negative effect due to the preparation methodics. Further study should focus on optimizing the shape, size and amount of additive nanoparticles. Keywords: photocatalysis, antimicrobial efficacy, nanoparticles, synthesis, titanium dioxide
The diploma thesis deals with efficiency of nanoparticles-additivation on photocatalytic and antibacterial activity of SiO2 / TiO2 suspension Balclean. Ag, ZnO and CuO nanoparticles were elected for additivation and synthesized under laboratory conditions. In the synthesis of nanoparticles, emphasis was placed on the simplicity and efficiency of the used methods, such as the chemical reduction method for Ag and the precipitation method for ZnO and CuO. Characterization of morphology and size using scanning electron microscopy was performed for prepared nanoparticles and it was further complemented with energy dispersion analysis. The average size of Ag particles was about 220 nm, whereas the diameters of ZnO and CuO particles were about 70 nm. The prepared particles were added to Balclean with the concentration of 1 wt%. Antimicrobial activity was assessed according to ISO 27447; 2009, E. Coli was used as a model organism. The addition of particles in all cases led to in a significant increase in antibacterial activity, which was observed on both UV exposed sample and sample kept in the dark. Photocatalytic efficiency was assessed by NOx degradation according to ISO 22197-1; 2007 and by the degradation of methylene blue according to ISO 10678; 2010. An increase in photocatalytic efficiency in case of additivation of ZnO was observed, whereas photocatalytic activity decreased in samples with addition of Ag (respectively CuO). This decrease was probably caused by too high concentration of added particles, in the case of silver, the large particle diameter probably had a negative effect due to the preparation methodics. Further study should focus on optimizing the shape, size and amount of additive nanoparticles. Keywords: photocatalysis, antimicrobial efficacy, nanoparticles, synthesis, titanium dioxide
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fotokatalýza, antimikrobiální účinnost, nanočástice, syntéza, oxid titaničitý, photocatalysis, antimicrobial efficacy, nanoparticles, synthesis, titanium dioxide