Darinka Fakin

Sorption Properties of Flax Fibers Depending on Pretreatment Processes and their Environmental Impact

The purpose of this research was to investigate the influence of different pre-treatment processes, on the sorption properties of flax fibers and the impact of residual treatment baths on environmental pollution. Flax fibers were subjected to different scouring processes (alkaline, acidic and enzymatic scouring) and, subsequently, oxidative bleaching, with and without application of ultrasound energy. The sorption properties of differently pre-treated flax fibers were defined by iodine sorption value, moisture sorption, and water retention power. The residual pre-treatment baths were ecologically analyzed using total organic carbon, chemical oxygen demand, biochemical oxygen demand and biological degradability. The obtained results indicated that the alkaline, acidic and enzymatic scourings of flax fibers have a significant effect on their sorption properties and, consequently, on the bleaching process. The application of ultrasound in the scouring and bleaching bath increased the fiber weight loss and water retention power of the flax fibers, as well as improving the ecological parameters. The optimal pre-treatment process was enzymatic bioscouring because it provided a lower weight loss, a better absorptivity of the flax fibers, and is less environmentally harmful.

Enhanced catalytic activity of the surface modified TiO2-MWCNT nanocomposites under visible light.

Fusing multiwall carbon nanotubes (MWCNTs) with TiO2 at the nano-scale level promotes the separation of those electron-hole charges generated upon UV and daylight irradiation. In this study, we investigated facile sonochemical synthesis, combined with the calcination process for the preparations of TiO2-MWCNT composites with different mole ratios of titanium and carbon. In order to produce stable nano dispersions we exploited an innovative biotechnology-based approach for the covalent functionalizations of TiO2-MWCNTs with in-situ synthesized soluble phenoxazine dye molecules. The none and functionalized TiO2-MWCNTs composites were analyzed by a range of analytical techniques including XRD, Raman, XPS, SEM and UV-vis diffuse reflectance spectroscopy (DRS), and dynamic light scattering (DLS). The photocatalytic activity was evaluated toward the liquid-phase degradation of MB in aqueous solution under both UV and visible light irradiation. TiO2-MWCNTs with optimized mole ratio exhibit much higher photocatalytic activity and stability than bare TiO2. The as-prepared TiO2-MWCNTs photocatalyst possessed good adsorptivity of dyes, extended light absorption range and efficient charge separation properties simultaneously. The results indicated that the soluble phenoxazine dyes and amino-benzenesulfonic acid monomers were covalently grafted on to the surfaces of TiO2-MCNTs, which promoted good aquatic dispersibility and extended light absorption, resulting in increased photocatalytic efficiency.

Color and electrical resistance evaluation of cotton fabrics composed of stainless steel yarns treated with direct and reactive dyes

The aim of this work was to investigate the color change of cotton fabrics with stainless steel yarns incorporated. In order to establish the impact of conductive yarns’ composition properties in the fabric, concentrations and two different dyeing profiles based on direct and reactive dyes chemistry were applied. The success of this novel e-textile design was evaluated colorimetrically with two different dye concentrations as well through various linear electrical resistances to obtain solid statistical conclusions. The dyed samples were colorimetrically evaluated and the electrical resistances of conductive yarns inside the fabric structure were compared and discussed statistically before and after dyeing. The results provided evidence that dyeing has great influence on electrical resistances of conductive yarns used as transmission lines for electro-textile applications. The greatest changes in electrical resistances were observed with samples including thin conductive yarns and untwisted conductive yarn after dyeing processes. Additionally, it can be concluded that the presence of stainless steel conductive threads significantly retards the dyeing processes depending on the dyestuff concentration and weave type, resulting in major color differences, especially when plain weave type is used or the dyestuff concentration is less than 1% for twill and sateen weaves.

Optimization of removal of colour and organic pollutants from textile wastewater treated with UV/H2O2 adopting the Plackett–Burman factorial design

Abstract In the research work presented here, a Plackett–Burman two-level partial factorial design was adopted as a multivariate strategy to determine the optimum UV/H2O2 process conditions for maximizing the treatment efficiency of dye-rich textile effluents. The influence of wastewater parameters, i.e. type and concentration of dye (C Dye), 100–300 mg/L; concentration of NaCl (C NaCl), 2.5–3.5 g/L; and concentration of urea (C Urea), 5–15 g/L; and the amount of NaOH (C NaOH), 1–2.4 mL/L; as well as the operational parameters, i.e. intensity of UV irradiation (I UV), 1.2–1.4 kW; the amount of H2O2 , 0.7–8.3 mL/L; and treatment time (t), 6–30 min; on the colour and the removal of organic pollutants was investigated. After determining seven variables, laboratory-scale experiments were conducted using two synthetically-prepared wastewaters solutions that were polluted with two structurally different reactive dyes and selected chemicals. The assessment of the UV/H2O2 pilot plant’s performance was by monitori...

Influence of Enzymatic Pretreatment on the Colours of Bleached and Dyed Flax Fibres

SUMMARY In this paper the effect of enzymatic bioscouring on the bleaching and dyeing of flax fibres was studied in comparison with conventional alkaline scouring. Enzymatic bioscouring was performed with a commercial multi-enzyme system consisting of pectinases, hemicellulases and cellulases. The enzyme and alkaline scoured flax fibres were subsequently oxidatively bleached with hydrogen peroxide and dyed with direct dye C.I. Direct Red 80 under the same conditions. The efficiency of both the scouring and bleaching processes was evaluated by weight loss and the whiteness of the bleached samples was determined according to CIE formula. The exhaustion profile of the used dye was followed on-line during the dyeing process using absorbance measurement. The colours of bleached and dyed samples were evaluated using CIELAB colour values. The residual pretreatment and dyeing baths were ecologically analysed with COD, TOC and BOD5. The obtained results indicate that enzymatic scouring provides a lower weight loss, a higher degree of whiteness, comparable dyeing properties and is more environmentally friendly.

Fabric hand of a dry finished wool fabric

The appearance and hand of end-use fabrics has become more and more important when purchasing textile fabrics. The finishing parameters have complex influences on the large number of changes that occur in fabric properties during finishing processes. This study focused on the influences of different finishing parameters on mechanical and surface properties in order to discover the most appropriate finishing process according to the requirements of fabric handle and appearance. The KES-F system was used to evaluate fabric hand objectively, as well as the mechanical and surface properties of a woven wool fabric. Four finishing processes were selected, which differed in relation to the temperature when drying (T1=160 °C, T2=180 °C) and processing conditions during autoclave decatizing (T1=95 °C, p1=0.4 bar, T2=110 °C, p2=1 bar). The effect of the influential parameters inside four different finishing processes on the mechanical properties and hand of a selected woven fabric was evaluated using the analysis of variance. The results show that tensile properties are much more influenced by the belt pressing process while bending and shear properties are influenced by continuous decatizing process, which is the process that mostly improves fabric stability at the beginning of the dry finishing cycle. When the primary and total hand values were observed, it could be seen that applying chemicals during belt pressing had some consequences, the impacts of which could be observed directly in the resulting hand values.

Thermal, Mechanical and Optical Features of Aluminosilicate-Coated Cotton Textiles via the Crosslinking Method

The presented study focuses on the development of a pad-dry-thermofix functional coating process using a mixture of microporous aluminosilicate particles in diverse bath formulations to impart UV-ray-blocking, thermal stability and easy-care properties to the cotton fabric. The results of Scanning Electron Microscopy (SEM) and X-ray powder Diffraction (XRD) revealed the presence of three different types of zeolites within the examined sample, i.e., the largest amount being zeolite A, followed by the zeolite X, and the zeolite ZSM-5. The surface characterization results of zeolite-coated/cross-linked textiles provided evidence of acceptable UV-ray-blocking properties and increased thermal stability, as well as enhanced tensile strength and breaking tenacity without considerably decreasing the whiteness degree. Moreover, the dry crease recovery angle increased for the cotton fabric cross-linked via an mDMDHEU, and decreased significantly using 30 g/L zeolites negatively influencing qualitative values. TG/DTA results have proven the enlarged thermal stability of aluminosilicate-coated cotton, although combustion was not prevented.

Surface engineering of TiO 2 -MWCNT nanocomposites towards tuning of functionalities and minimizing toxicity

Multiwall carbon nanotubes were coupled with titanium dioxide (in different mole ratios of titanium and carbon) at the nano-scale, using a simple sonochemical and calcination process. The titanium dioxide-multiwall carbon nanotubes nanocomposites were for the first time surface modified with an innovative biotechnology-based reaction by using laccase to activate and covalently graft gallic acid dimers/oligomers/polymers on the nanocomposite surface in order to impart new functionalities and to minimize the nanocomposites’ toxicity. Structure of the titanium dioxide-multiwall carbon nanotubes, before and after surface modification, was investigated with X-ray powder diffraction, infrared, and UV-visible diffuse reflectance spectroscopy analysis, and scanning electron microscopy. The results indicated preferential formation of anatase titanium dioxide on one hand and covalent grafting of gallic acid dimers/oligomers/polymers functionalities on the nanocomposite surface, on the other. After modification, the antioxidant activity was analyzed using 2,2-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid) (ABTS) and photocatalytic activity toward the liquid-phase degradation of methylene blue in aqueous solution under both UV and visible light irradiation. Up to 98% antioxidant activity of the surface modified nanocomposites was established after 24 h of incubation, whereas non-modified nanocomposite induced the formation of the ABTS•+ radicals. In addition, 1.3-2.8-fold reduction in photocatalytic activity was achieved, depending on the irradiation. Accordingly, the gallic acid dimers/oligomers/polymers modified titanium dioxide-multiwall carbon nanotubes appear to simultaneously exhibit photocatalytic activity with an ability to scavenge free radicals, and can thus be considered as engineered nanoparticles with low toxicity.Graphical Abstract

The performance of a fixed-bed treatment system packed with layered textiles for their filtration/adsorption potential for salt and organic pollutant

Abstract The main contribution of the research work presented here was to select and investigate a few commercially available textiles to study their filtration/adsorption potential for salt and total organic carbon (TOC) reduction during wastewater treatment. First, several physical–mechanical properties, such as tensile strength, thickness, weight, density and structural aspect of two woven (polyamide and polyester) and two nonwoven (polypropylene [PP] and PP/polyethylene [PE]) textiles, were determined. Also, the void amount and total void area percentage of textiles were measured, which influence the wastewater flow (clog) and filtration efficiency. With the intention of examining the adsorption ability of the selected textiles, kinetic experiments were carried out in shake-flasks using three commonly-used salts. Afterwards, small-scale column experiments were conducted in a continuous-flow operation to assess the TOC and salt reduction. It was found that both nonwoven textiles (either made from PP or...

Changes in a knitted fabric’s surface properties due to enzyme treatments

Enzyme treatment technologies in textile processing have become commonly-applied techniques for the modification of fabric-handle appearance, and other surface and mechanical characteristics of fabrics. Most studies have focused on understanding the impact of enzyme treatments on the fabric preparation, dyeing, and finishing processes of woven fabrics, whilst only limited research has been reported regarding any enzymatic effects on the surface and handproperties of knitted fabrics. The aim of this study was to analyze the effects of two different enzymes Trichoderma reesei whole cellulase, and enriched (EGIII) endoglucanase cellulase, at three different enzyme dosages on 100 % cotton interlock knitted fabric. This was in order to evaluate certain surface properties such as pilling, friction. and geometrical roughness. Furthermore, the compression and tactile properties of knitted fabric were also analyzed. The results show that treatment conditions with enzyme Trichoderma reesei whole cellulase had the more pronounced effect on the surface properties compared to the enriched EGIII enzymes. In general, it can be concluded that both types of enzymes improved the surface properties and hand when compared with the silicone softener-treated reference sample of interlock knitted fabric, as is statistically confirmed by one-way analysis of variance.