Małgorzata Iwona Szynkowska

Facile and durable antimicrobial finishing of cotton textiles using a silver salt and UV light

In this study, we present facile antimicrobial finishing of cotton textiles. Screen printing was used for surface-finishing of cotton using a printing paste containing silver nitrate. UVC irradiation was applied to convert silver nitrate into a color product, thus also changing the color of the textiles. The color, its strength and stability of samples, depend on absorbed UVC energy and the formula of the printing paste. Scanning electron microscopy with the energy dispersive X-ray spectrometry revealed formation of silver particles on cotton threads; X-ray diffraction analysis and the time-of-flight secondary ion mass spectrometry did not provide clear information on these products. Microbiological studies revealed that the samples inhibited proliferation of Escherichia coli, Bacillus subtilis and Staphylococcus aureus. Washing fastness tests confirmed resistance of the samples to at least 50 washings. Additionally, the inhibition zones increased as the number of washing cycles increased, which is unique for such samples. This work also presents an approach to the design of antimicrobially finished workwear.

Novel Pd–Cu/ZnAl2O4–ZrO2 Catalysts for Methanol Synthesis

Monometallic Cu and bimetallic Pd–Cu catalysts promoted by ZrO2 were prepared using impregnation method. The physicochemical properties of catalytic systems were investigated using BET, scanning electron microscopy–energy dispersive spectrometry, temperature programmed reduction-H2, X-ray diffraction, Fourier transform infrared techniques. Catalytic activity was studied in fixed bed reactor under high pressure (4.8 MPa). The results show that addition both Pd and ZrO2 increases the methanol yield. Zirconium oxide improved the dispersion and reducibility of the copper catalysts. The presence of adsorption species attributed to b-HCOO–Zr, b-HCO3–Zr, m-CO3–Zr species on the surface of ZrO2 promoted catalysts was confirmed. The high activity of promoted palladium catalysts is explained by synergistic effect between Pd and Cu.Graphical Abstract

Human hair analysis in relation to similar environmental and occupational exposure

The aim of this work was to assess the influence of various factors on the elemental composition of the investigated hair samples. The studied population consisted of students of Faculty of Chemistry at Lodz University of Technology and included 95 subjects. The following elements: Co, Cr, Cu, Li, Sr, Pb were determined by inductively coupled plasma time-of-flight mass spectrometry ICP-TOF-MS. The obtained results were elaborated using Statistica ver. 10.0 software. Statistically significant differences were observed for the content of Cr, Li, Pb and Sr as the impact of sex, and Sr-as the effect of cosmetic treatment. Based on the calculated Spearman correlation coefficients, a statistically significant correlation between the concentration of pairs of metals were found for Pb=f(Co, Cr, Cu); Sr=f(Cu); Li=f(Cr), Cr=f(Li, Pb), Co=f(Pb) and Cu=f(Pb, Sr). A statistically negative correlation was obtained for Sr-Li. In the population two groups were distinguished: males and females; smokers and non-smokers.

The use of rye, oat and triticale straw as fillers of natural rubber composites

Up to date, there are no evident research works carried out to improve and verify the physical, mechanical, barrier and damping properties of bioelastomer composites with addition of straw. Moreover, the problem of improving the reuse of straw is now demanding attention in the major cereal-growing areas of the world. The aim of this study was to receive knowledge of characteristic and producing multifunctional elastomer biocomposite filled with straw. Rye, oat and triticale were found to be active fillers improving wide range of rubber composites functional properties like: static mechanical, damping, barrier properties and hardness. The use of straw as a filler also increased cross-linking density. Dynamic-mechanical analysis indicates the presence of strongly developed secondary structure of examined fillers in vulcanizates. Moreover, all of the vulcanizates proved to be resistant to thermo-oxidative degradation. The application of straw as a filler allowed obtaining composites with lower value of oxygen index, that reflecting higher tendency of smoke generation. Introducing the straw into polymer matrix reduced the manufacturing costs of composites through the use of a significant amount of inexpensive and renewable filler. Furthermore straw fillers modify natural rubber, obtaining high-performance materials with meaningly enhanced applications.

Shape-programmed inkjet-printed silver electro-conductive layers on textile surfaces

The inkjet-printing technique was used to deposit a commercial silver nanoparticle ink in order to fabricate the electro-conductive layers directly on the different natural, synthetic, blend and mineral textile fabric surfaces with simultaneous sintering at 130℃ during printing process. This modification eliminated the necessity of sintering of silver prints in a box oven and significantly minimised ink spreading over the fabric. The silver nanoink used was characterised by means of ultraviolet-visible spectrometry, dynamic light scattering and transmission electron microscopy. The changes in surface resistance of the fabrics with the silver-deposited layers have been measured by means of the four-probe method. The morphology of the silver layers has been observed by optical microscopy and scanning electron microscopy. The conducting layers were also characterised chemically by means of energy dispersive spectroscopy. The changes in surface resistance of the silver inkjet-printed textiles were evaluated in the bending tests and after the rubbing, washing and dry-cleaning processes. The obtained results proved that the proposed shape-programmed inkjet-printing method was very simple, giving an excellent adhesion of the inkjet-printed silver layers to the substrates and ensuring a very low surface resistance. The studies have confirmed the usefulness of the ink applied for inkjet printing of silver electrodes and their good tolerance to bending, washing and dry-cleaning processes.

Fischer–Tropsch synthesis over various Fe/Al2O3–Cr2O3 catalysts

Monometallic iron supported catalysts were prepared by the impregnation method and tested in Fischer–Tropsch (F–T) synthesis. The activity tests performed in the studied reaction showed that the composition of the catalyst strongly influences the reactivity of the catalytic systems in the F–T reaction. It was also found that the system which showed the highest content of iron species on the catalyst surface exhibited the highest yield in F–T reaction. In addition, the most active catalyst also showed high specific surface area, high total acidity value and the highest amount of iron species on the catalyst surface. The analysis of the liquid product of F–T synthesis confirmed the occurrence of aliphatic, branched and unsaturated linear hydrocarbons.

Carbon Deposits Formed on the Surface of Ru–Ni Catalysts During the Mixed Reforming of Methane Process

Monometallic nickel and bimetallic ruthenium–nickel catalysts supported onto aluminum oxide without additives and aluminum oxide modified with MgO and CaO were prepared by an impregnation method. The catalysts were tested in the process of the mixed reforming of methane, and their properties were characterized by thermogravimetry, scanning electron microscopy, and X-ray diffractometry. The total organic carbon content of the catalysts was also measured. The promoting effect of ruthenium and structural promoters on the catalytic activity of Ni/Al2O3 was confirmed. The Ru–Ni/MgO–Al2O3 catalyst exhibited the highest stability and activity; this fact can be explained by the increased adsorption of methane on the surface of ruthenium–nickel clusters.

Supported Ru−Ni Catalysts for Biogas and Biohydrogen Conversion into Syngas

Catalytic properties of monometallic Ni and bimetallic Ru–Ni supported on Al2O3, CaO–Al2O3, and MgO–Al2O3 have been studied in mixed reforming of methane. Physicochemical properties of the catalytic systems have been studied by X-ray diffraction, scanning electron microscopy with energy dispersive spectroscope and temperature-programmed reduction by hydrogen. It has been shown that, of all the studied samples, the highest conversion of methane and carbon dioxide is achieved in the presence of the Ru−Ni/MgO–Al2O3 bimetallic catalyst. Temperature-programmed reduction has confirmed the effect of hydrogen spillower from ruthenium to NiO. The formation of Ru–Ni alloy has also been found.

The impact of demographic factors, behaviors and environmental exposure to mercury content in the hair of the population living in the region of Lodz (central Poland)

The aim of this work was to access the influence of different factors such as sex, age, fish consumption, hair dyeing or smoking habit on the content of mercury in human hair samples. The research was carried on 444 samples (102 males and 342 females) collected from the population of people living in the region of Lodz (central Poland). The content of mercury in human hair samples was determined using the Mercury Analyzer MA 3000 (Nippon Instruments, Japan). The obtained results were elaborated using Statistica ver. 10.0 software. The mean value of mercury in investigated human hair samples was found to be 0.174±0.137mg/kg. We observed the statistically significant correlations (p<0.05) between the content of Hg in hair of the studied population and factors such as gender, age, and fish consumption. However, no statistically significant differences were found in relation to cosmetic treatment such as hair dyeing or smoking.