Diana Coman

Zinc oxide-linen fibrous composites: morphological, structural, chemical and humidity adsorptive attributes:

The main result and characterizing aspect of the research consists of the effectiveness of novel ZnO-linen fibrous composites synthesized by means of hydrothermal deposition of zinc oxide onto linen fibers, with the assistance of two surfactants. This has a direct implication on the relationship between the morphological, structural and chemical attributes and water vapor sorption-desorption behavior. Methodology consists of the hydrothermal synthesis of zinc oxide onto linen fibrous substrates previously grafted with MCT-β-CD (MonoChloroTriazinyl–β-CycloDextrin) via a hydrothermal process. The morphological, structural and chemical properties of the samples were examined, in terms of a co-assisted investigation system: SEM images for the morphology, EDX analysis for surface composition, FTIR spectroscopy and X-ray diffractometry for structural samples features. Dynamic vapor sorption (DVS) analysis will complete this study. According to the results provided by the characterization technique, the uniformity of the fabric coated with ZnO powder hydrothermally synthesized with assistance of CTAB (Cetyl TrimethylAmmonium Bromide) is better than that of ZnO powder hydrothermally synthesized in the presence of Pluronic P123 and possesses good washing fastness. X-ray diffraction results have indicated that the composites exhibited a more ordered structure and higher water vapor sorption-desorption capacity (obtained by DVS analysis) compared with those of the reference fibrous linen supports.

Zinc Oxide — Linen Fibrous Composites: Morphological, Structural, Chemical, Humidity Adsorptive and Thermal Barrier Attributes

Nanoparticles are extremely reactive, due to their high surface energy, and most systems undergo aggregation without protection of their surfaces. To eliminate or minimize generated waste and implement sustainable processes, recently green chemistry and chemical processes have been emphasized for the preparation of nanoparticles [2]. Much attention is now being focused on polysaccharides used as the protecting agents of nanoparticles. As stabilizing agent soluble starch has been selected and as the reducing agent in aqueous solution of AgNO3 for silver nanoparticle growth, and a-D-glucose, has been elected. To maintain noble metal (platinum, palladium and silver) nanoparticles in colloid suspension, Arabinogalactan has been used as a novel protecting agent for [3]. Synthesized platinum, palladium and silver nanoparticles with narrow size distribution have been achieved by using porous cellulose

Coloristic and antimicrobial behaviour of polymeric substrates using bioactive substances

A major concern in reducing microbial contamination of healthcare and hygiene products motivated us to seek viable alternatives in order to create such barriers. The antimicrobial and anti-oxidant effects of natural extracts are well-known, their application onto polymeric supports is still challenging in terms of investigation. To our knowledge, the method of natural dyeing of different polymeric substrates using bioactive substances derived from black currant and green walnut shells, in conjunction with biomordants, and their long term effects have not been very consistently reported. The main objective of the study is based on the comparative study of different polymeric fibrous substrates dyed by means of laboratory scaled classic methodology with extracts from black currant fruits and green walnut shells, with the assistance of conventional and biomordants (copper sulphate, citric and tannic acids). The assistance of biomordant in the dyeing process seems to conduct to improved synergetic colouring and antibacterial performances. The main results demonstrated that the extract of green walnut shells reinforced by the biomordants solutions expressed the best antimicrobial behaviour. The present research is a milestone in the identification of potential technological alternatives applied in dyeing of synthetic and natural textile supports, quantified and controlled by antimicrobial response correlated with colorimetric features.

Waste-water management by a comparative research of photocatalytic performance belonging to coupled ZnO/SnO2 nanocomposites against degradation of textile dyes

Coupled ZnO/SnO2 nanocomposites were successfully prepared with different molar ratios (1/1-1/10) using a homogeneous co-precipitation method. The structural properties of the obtained oxides were evaluated using different techniques: N2 sorption, Infrared spectroscopy, UVDR spectroscopy for solid compounds and scanning electron microscopy (SEM). The photocatalytic activity of the samples was tested for the bleaching of eosin Y. The photocatalytic process occurs under the illumination of an UV lamp, emitting light at 254 nm. The influence of the wavelength and the ZnO:SnO2 molar ratio over the photocatalytic efficiency was studied.