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V doktorski disertaciji je predstavljena raziskava razvoja novega okolju prijaznega postopka in situ sinteze delcev cinkovega oksida (ZnO) na bombažu (CO) in poliestru (PET), kjer so bili namesto kemičnih reducentov uporabljeni vodni ekstrakti odpadnega rastlinskega materiala (invazivne tujerodne rastline in živilski odpadki) in namesto kemične alkalije uporabljen vodni ekstrakt lesnega pepela. Receptura in situ sinteze ZnO je bila optimizirana s proučevanjem različnih metod sinteze in vplivov parametrov sinteze (vrsta in koncentracija prekurzorja in »zelenih« reducentov, vrsta reducenta, vrstni red reagentov pri sintezi, čas in temperatura sinteze). Zaradi različne vsebnosti fenolnih skupin (TPC) »zelenih« reducentov, ki vplivajo na stopnjo antioksidativnosti in redukcijske sposobnosti reducenta, se je kot ključni parameter za uspešno oblikovanje ZnO direktno na CO in enakomerno porazdelitev po vlaknih ter odlično sposobnost tkanine blokiranja ultravijoličnega (UV) sevanja (50+), izkazal vrstni red reagentov (Alkalija–Zn-prekurzor–Reducent). Cinkov acetat je bolj primeren prekurzor za sintezo na CO kot cinkov nitrat, saj se s slednjim mehanske lastnosti tkanine močno poslabšajo. Ugotovljeno je bilo, da se lahko glede na uporabljen »zeleni« reducent prilagodi tudi omočljivost CO, in sicer reducenti z višjo vsebnostjo TPC omogočajo hidrofilne lastnosti, tisti z nižjo vsebnostjo TPC pa hidrofobne. Pri sinteznem postopku na PET je bila vpeljana plazma kisika za povečanje reaktivnost tkanine do reakcijskih raztopin in kasneje kot zamenjava alkalije. S plazmo se je povečala hidrofilnost PET in enakomerna adsorpcija reagentov, kar je omogočilo homogenost in situ sintetiziranih ZnO po celotni tkanini oz. vlaknih. Pri tem se je s številom plazemskih obdelav višala tudi UV zaščita tkanine, kot posledica zvišanja vsebnosti ZnO. Tako alkalija kot plazma kisika vplivata na povečanje aktivnih mest na PET, ki predstavljajo nukleacijska mesta prekurzorja za oblikovanje ZnO s pomočjo »zelenega« reducenta. S stališča čim bolj okolju prijazne in situ sinteze ZnO, zmanjšanja porabe vode, časa priprave reagentov in homogenosti in situ sintetiziranih ZnO na tkanini, se namesto alkalije lahko uporabi plazma kisika. This doctoral dissertation presents the development of a novel, environmentally friendly process for in situ synthesis of zinc oxide (ZnO) on cotton (CO) and polyester (PET) using aqueous extracts of invasive alien plants and food waste instead of classical chemical reducing agents, and aqueous extract of wood ash instead of chemical alkali. The ZnO synthesis procedure was optimised by studying different synthesis methods and parameters (type and concentration of precursor and »green« reducing agent, the order of synthesis solutions, synthesis time and temperature). Due to the different amounts of phenolic compounds (TPC) present in the »green« reducing agents, the order of the synthesis solutions (Alkali䀒Precursor-Reducing agent) proved to be a key parameter influencing the successful in situ synthesis and the uniform distribution of ZnO particles on fibres and consequently achieving the excellent ultraviolet (UV) protective properties (50+) of the CO fabric. Zinc acetate is a more suitable precursor for the in situ synthesis of ZnO than zinc nitrate, since with the latter, mechanical properties of the fabric are greatly impaired. Depending on the »green« reducing agent used, the wettability of the CO fabric can be adjusted. The reducing agents with higher TPC values enable hydrophilic properties, while the ones with lower TPC values enable hydrophobic properties of the CO. Oxygen plasma treatment was incorporated into the synthesis process on PET, first to increase the reactivity of PET to the synthesis solutions, and finally as a substitute for alkali. Plasma increased the hydrophilicity of PET and enabled an even adsorption of the reagents, resulting in uniform distribution of the in situ synthesised ZnO on the fabric. As the number of plasma treatments increased, the UV protection of fabrics also increased, due to higher ZnO content. Both alkali and oxygen plasma increase the amount of active binding sites on PET, which represent precursor nucleation sites for the formation of ZnO using »green« reducing agent. From the point of view of the most environmentally friendly in situ synthesis of ZnO, reduction of water consumption, preparation time for reagents and homogeneity of in situ synthesized ZnO on the fabric, oxygen plasma can be used instead of alkali.

This work presents the novel and entirely green in situ synthesis of zinc oxide nanoparticles (ZnO-NP) on cotton fabric. Pomegranate peel extract was used as a reducing agent and wood ash extract was used as an alkali source for the formation of ZnO-NP from zinc acetate. Four different synthesis methods, which varied in drying between immersion of fabric in the active solutions for synthesis and the use of padding and ultrasonication, were investigated to evaluate the most suitable one to achieve excellent ultraviolet (UV) protective properties of the functionalized textile. For comparison, the cotton fabrics were also functionalized with each active solution separately or in a combination of two (i.e., Zn-acetate and plant extract). Scanning electron microscopy (SEM), inductively coupled plasma mass spectroscopy (ICP-MS), Fourier transform infrared spectroscopy (FTIR), X-ray diffractometry (XRD) analysis, and atomic force microscopy (AFM) confirm the successful formation of ZnO-NP on cotton. Among the synthesis methods, the method that included continuous drying of the samples between immersion in the active solutions for synthesis (Method 4) was found to be the most suitable to deliver uniformly impregnated cotton fibers with numerous small ZnO wurtzite structured crystals and excellent UV protection, with a UV protection factor of 154.0. This research presents an example of a green circular economy where a bio-waste material can be used to produce ZnO-NP directly on cotton at low temperatures and short treatment times without the addition of chemicals and enables the production of cellulosic fabrics with excellent UV protection.

V diplomskem delu je bila proučena in situ sinteza nanodelcev srebra na surovi bombažni tkanini. Kot prekurzor je bil uporabljen srebrov nitrat, kot reducenti pa vodni ekstrakti rastlinskih komponent živilskega odpadka (listi zelenega čaja, koščice avokada in olupki granatnega jabolka) in invazivnih tujerodnih rastlinskih vrst (korenika japonskega dresnika, plodovi octovca in cvetovi zlate rozge). Za primerjavo je bila bombažna tkanina obdelana tudi samo v reducentih. Barvne vrednosti (vrednosti CIE L*a*b*) vzorcev in globina obarvanja (vrednosti K/S) so bile določene z refleksijskim spektrofotometrom. Zaščitne lastnosti obdelanih vzorcev proti ultravijoličnem sevanju (vrednosti UZF) so bile določene z uporabo UV-Vis spektrofotometra. Morfologija vlaken oziroma oblikovanih nanodelcev je bila opazovana z vrstično elektronsko mikroskopijo (SEM). Vsebnost srebra na vzorcih je bila določena z masno spektrometrijo z induktivno sklopljeno plazmo (ICP-MS). Vzorcem, kjer je bila in situ sinteza izvedena, so bile proučene tudi njihove protimikrobne lastnosti. Vodni rastlinski ekstrakti so reducirali srebrov nitrat v krogelno oblikovane nanodelce z različno velikostjo in vsebnostjo glede na posamezen reducent. Le-to je vplivalo na uspešnost redukcije rasti bakterij Escherichia coli in Staphylococcus aureus, ki je bila pri vseh tako obdelanih vzorcih odlična. Odlična zaščita proti UV-sevanju je bila izmerjena tako za vzorce z vsebnostjo srebra kot tudi za večino tistih brez prisotnosti srebra. Po večkratnih pranjih vzorci s formiranimi srebrovimi nanodelci še vedno nudijo odlično zaščito proti UV-sevanju, ostali obdelani vzorci pa so uvrščeni v prav dobro ali dobro zaščitno kategorijo. Prisotnost srebrovih nanodelcev vpliva tudi na temnejše barve, ki se odražajo v bolj rdečkastih in rumenkastih barvnih odtenkih. Po pranju večina vzorcev postane svetlejših in modrikastih. In situ synthesis of silver nanoparticles on raw cotton fabric was studied for Diploma thesis. Synthesis occurred directly on cotton when it was immersed in precursor solution of silver nitrate and after in water-extracts of food waste plant materials (green tea leaves, avocado seed and pomegranate peel) and invasive alien species (Japanese knotweed rhizome, Staghorn sumac fruit and Goldenrod flowers). For comparison, the cotton fabrics were treated also only with water-extracts. Colour values (CIE L*a*b) and colour depth (K/S values) were determined using a reflectance spectrophotometer. Ultraviolet protective properties of the samples (UPF values) were analysed using UV/VIS spectrophotometer. The morphology of fibres and formed nanoparticles was analysed using scanning electron microscopy (SEM). Silver content was determined using inductively coupled plasma mass spectrometry (ICP-MS). Antibacterial properties of the samples, where in situ synthesis was performed, were also analysed. Different size and content of spherical shaped nanoparticles were formed on fibres using water-extracts as reducing agents. Size and shape of silver nanoparticles influence the reduction of Escherichia coli in Staphylococcus aureus bacteria. The antimicrobial properties were excellent for the samples with synthesized nanoparticles. Furthermore, excellent protection against ultraviolet radiation was determined for the samples without and with formed nanoparticles. After twelve times washing cycles, the samples with silver nanoparticles still show excellent protection against ultraviolet radiation, all other sample were classified with very good or good protection category. The presence of nanoparticles on cotton also influences its colour, which is darker, with reddish and yellowish hue. Most of the samples become lighter and bluish after repetitive washings.