34 research outputs found
Dyeing of cotton with madder using (bio)mordants: effects on fastness and UV protection properties
This work aimed at studying the dyeing of cotton fabrics with madder extract using two biomordants,
quebracho tree extract (Schinopsis spp.) and laccase. Pre-treatment with quebracho increased the colour
strength, washing and UV light fastness, and UV protection, while laccase only shows an increase in
the UV light fastness. The application of biomordants together with the metal ones (aluminium or iron
salts) led to an improved UV light fastness compared to the samples mordanted only with metal salts.
Meanwhile, although the colour strength was lower than in the metal-mordanted samples, greater UV
protection factors were obtained in the samples pre-treated with quebracho or laccase and iron salt.Authors acknowledge the Portuguese Foundation for Science and Technology (FCT), FEDER funds by
means of Portugal 2020 Competitive Factors Operational Program (POCI) and the Portuguese
Government (OE), project Factor ST+ – grant number POCI-01-0247-ERDF-047124, for the research
grants of C.A., M.F., and R.R. Authors also acknowledge projects: UID/CTM/00264/2019 and
UID/CTM/00264/2021 of Centre for Textile Science and Technology (2C2T)
Dyeing of cotton with madder using (bio)mordants: effects on fastness and UV protection properties
Apresentação efetuada na 21th World Textile Conference - AUTEX 2022, em Lodz, Poland, 2022Portuguese Foundation for Science and Technology (FCT), FEDER funds by means of Portugal
2020 Competitive Factors Operational Program (POCI) and the Portuguese Government (OE),
project Factor ST+ – grant number POCI-01-0247-ERDF-047124, for the research grants of C.A.,
M.F., and R.R.Authors also acknowledge projects: UID/CTM/00264/2019 and UID/CTM/00264/2021 of Centre
for Textile Science and Technology (2C2T
Effect of plasma and cationization pre-treatiments on fastiness and UV protection of cotton dyed with madder
To achieve good colour depth and fastness of naturally dyed fabrics is necessary to use mordants, usually metallic salts, which are potentially harmful to the environment and human health. In this work, the effect of plasma and cationization pre-treatments on cotton fabrics dyed with natural dye madder extract was investigated as environmentally sustainable alternative processes. Air atmospheric dielectric barrier discharge (DBD) plasma treatment showed a slight improvement in fastness to washing and UV light when samples were dyed at pH 11. On the other side, cationization with poly(diallyldimethylammonium chloride) (PDDA) greatly improved the dye uptake onto cotton, but with poor fastness. Meanwhile, the simultaneous pre-treatment with metallic mordants improved significantly the fastness properties, being the PDDA/Fe pre-treatment, followed by dyeing at pH 5, the process which showed the best results regarding colour strength, fastness to UV light, and UV protection
Enhancing functionalization of health care textiles with gold nanoparticle-loaded hydroxyapatite composites
Hospitals and nursing home wards are areas prone to the propagation of infections and are
of particular concern regarding the spreading of dangerous viruses and multidrug-resistant bacteria
(MDRB). MDRB infections comprise approximately 20% of cases in hospitals and nursing homes.
Healthcare textiles, such as blankets, are ubiquitous in hospitals and nursing home wards and may be
easily shared between patients/users without an adequate pre-cleaning process. Therefore, functionalizing these textiles with antimicrobial properties may considerably reduce the microbial load and
prevent the propagation of infections, including MDRB. Blankets are mainly comprised of knitted
cotton (CO), polyester (PES), and cotton-polyester (CO–PES). These fabrics were functionalized with
novel gold-hydroxyapatite nanoparticles (AuNPs-HAp) that possess antimicrobial properties, due to
the presence of the AuNPs’ amine and carboxyl groups, and low propensity to display toxicity. For optimal functionalization of the knitted fabrics, two pre-treatments, four different surfactants, and two
incorporation processes were evaluated. Furthermore, exhaustion parameters (time and temperature)
were subjected to a design of experiments (DoE) optimization. The concentration of AuNPs-HAp in
the fabrics and their washing fastness were critical factors assessed through color difference (∆E). The
best performing knitted fabric was half bleached CO, functionalized using a surfactant combination
of Imerol® Jet-B (surfactant A) and Luprintol® Emulsifier PE New (surfactant D) through exhaustion
at 70 ◦C for 10 min. This knitted CO displayed antibacterial properties even after 20 washing cycles,
showing its potential to be used in comfort textiles within healthcare environments
Recovery of post-consumer textile waste garments from a new and environmentally-friendly approach: method and properties
This research was funded by FEDER funds through POCI under the “Portugal 2020” program, under the project FATORST+ POCI-01-0247-FEDER-047124, and by National Funds through Fundação para a Ciência e Tecnologia (FCT). Talita Nicolau and Cátia Alves acknowledge FCT, MCTES, FSE, and UE PhD grants 2022.15386.BD and 2022.10454.BD, respectivel
Effects of conductive and non-conductive materials on the activity of a hydrogenotrophic methanogen
Several conductive materials (CM), such as carbon nanotubes (CNT), activated carbon (AC), and magnetite, have been reported to mediate interspecies electron transfer in methanogenic environments. However, CNT also accelerated methane production (MP) of pure cultures of methanogens. We hypothesize that other CM and also non-CM may affect the methanogenic activity of pure cultures. For that purpose, we incubated the hydrogenotrophic methanogen, Methanobacteriun formicicum strain DSM 1535T, with AC, zeolite (Zeo), sand and glass beads (at 0.5 g/L), and followed MP. All materials reduced lag phases preceding the MP, and the time for complete conversion of H2/CO2 to methane. The best results were obtained with Zeo, since total hydrogen conversion occurred in less than 5 days (instead of 8 days as in the control incubated without materials). Approximately 5 days with sand, and 6 days with glass beads and AC, were necessary to achieve the complete conversion. The lag phases with AC were quite short (1 day) when compared with the control assay without materials (5 days). The initial MP (determined during the first 3 days of incubation) was improved 16 times with Zeo and 11 times with AC, when compared with the cultures incubated without materials. The results show that there is not a direct relationship between conductivity and the improvement of methanogenic activity. Other physicochemical properties of the materials might be related with the beneficial effects towards methanogens.info:eu-repo/semantics/publishedVersio
Pure cultures of hydrogenotrophic methanogens are affected by modified activated carbons, zeolite, sand and glass beads
The metabolism of hydrogenotrophs has been showed to be improved in the presence of carbon nanotubes, which is relevant since they are crucial microorganisms in the conversion of waste to methane1. In this study, we investigated if other materials, with different physicochemical properties, also affect the hydrogenotrophic activity of Methanobacterium formicicum.
M. formicicum was incubated separately with 0.5 g/L of sand, and commercial zeolite, glass beads and activated carbon (AC0) with and without modifications on the AC0 surface. Modifications were obtained by chemical oxidation with HNO3 (AC_HNO3), H2SO4 (AC_ H2SO4) or both (AC_HNO3_ H2SO4) and thermal treatments.
All materials, with exception of AC_HNO3_ H2SO4, improved the methanogenic activity. Carbon-based materials significantly reduced the lag phases preceding methane production (MP) (from approximately 5 days in the control to circa 1 day). Zeolite, sand and glass beads also reduced the lag phases but less than carbon materials (i.e., from 5 days to 1.5, 2.7 and 3.5 days, respectively). Additionally, exponential MP rates were up to 1.5 times higher in the assays with non-carbon materials.
All materials tested have different physical/chemical properties including conductivities, but all stimulated the methanogenic activity. Thus, further studies are necessary to identify the mechanisms behind the underlying observations.info:eu-repo/semantics/publishedVersio
Zeolite stimulates the activity of microbial enrichments converting butyrate to methane
Conductive materials have been tested as a strategy to improve methane production (MP) in anaerobic digestion (AD) processes1,2. The effect of zeolite (0.5 g/L) towards microbial enrichments converting butyrate (10 mmol/L) to methane was investigated and compared with a microbial enrichment in the absence of the material. The enrichments were initiated with granular anaerobic sludge from a brewery WWTP as inoculum. Incubations were carried out under strict anaerobic conditions (at 37 °C) and periodically transferred to fresh medium.
The results showed that, after an initial adaptation period (3 transfers), the presence of zeolite significantly accelerated the total conversion of butyrate to methane, since it took approximately 30d with zeolite and around 45d without zeolite. However, both enrichment cultures after extended adaptation (more than 8 transfers) behaved similarly, degrading butyrate in approximately 15d. Nevertheless, zeolite addition to active butyrate enrichment cultures without previous contact with zeolite, slightly accelerated MP, while the highly adapted zeolite-enrichment decreased activity when incubated without zeolite.
Thus, the presence of zeolite showed to stimulate the microbial activity enhancing MP from butyrate degradation. This material possess natural ion-exchange properties, absorptive capacity and could function as a support for biomass which makes its application very attractive to AD processes.info:eu-repo/semantics/publishedVersio
Antibacterial hydrogel dressings and their applications in wound treatment
Antimicrobial hydrogels, both in semi-stiff sheets and amorphous form, have been extensively
studied for wound management mainly owing to their high-water content, lower wound
adherence, promoted autolysis debridement, epithelial migration, and granulation growth.
Benefiting from the recent advances in materials science, biotechnology, and a growing
understanding of wound microbiology, an extensive variety of antimicrobial hydrogels have
been developed. These novel antimicrobial hydrogels can prevent and control microbial
infection. In addition, they possess wound healing functions for improved wound management.
This chapter will provide a comprehensive summary of the current studied antimicrobial
hydrogels in literature and available hydrogel dressings in the market, including their design,
fabrication method, and wound management efficacy in vitro or in vivo. The detailed and
critical discussion of the advantages and disadvantages of each type of hydrogel dressing will
provide insights into the future design of antimicrobial hydrogels for better management of
wounds in clinical application
Modification of nanocellulose
Nanocellulose (NC) represents a pivotal material for the sustainable strategies of the future. NC comprises cellulose nanofibrils (CNFs), cellulose nanocrystals (CNCs), and bacterial nanocellulose (BNC), each exhibiting unique and exceptional physicochemical properties. These properties encompass high specific surface area, high tensile strength, lightweight, biodegradability, good barrier properties, and high processing versatility. However, the range of properties and applications can be significantly expanded through the modification of NC, involving both chemical and physical methodologies, which introduce a plethora of functional groups to the densely populated hydroxyl groups present in pristine NC. The modification processes discussed in this chapter encompass chemical and physical modifications that were reported mostly within the last 5 years. The described methodologies emphasize the potential of NC as a substrate for advanced functional and sustainable material