Resumen de Dyeing and printing natural fibers with algae-based colorants
The crucial need for sustainable development has an immense impact on industrial evolution paving the path for a progressive transition towards a sustainable bioeconomy. Considering the pollutant evolution of the textile industry, approaches to exploring environmentally friendly alternatives to fossil-based resources and polluting processes have become the most current practice nowadays. In this sense, this study proposes the exploration of a sustainable alternative colorant material for coloration applications, from algae-based feedstock, considering the reduced environmental pressure embroiled by algae cultivation, colorant extraction, and its possible further textile application.
This study explores the viability of the use of algae-based colorants for their application in exhaustion dyeing and pigment printing coloration techniques for the textile industry. Micro and macroalgae strains selection was performed according to criteria ensuring facile and optimized cultivation and the provision of basic colors for the textile industry as blue (C-phycocyanin), red (R-phycoerythrin), yellow (ß-carotene), and green (Chlorophyll-a). Liquid colorant-rich extracts were employed in the selected textile finishing processes on natural fibers, like cotton and wool.
To approach the viability of these alternative sustainable colorants and enhance coloration properties and efficiencies, a series of auxiliaries were assessed, as conventional metallic and newly discovered mordants, and biomordants. Theoretical assumptions related to the plausible bonding among fibers-mordants-colorants were approximated. The auxiliaries implication in exhaustion dyeing and pigment printing processes were analyzed through a series of characterization tests, envisaging objective color characterization determined by the measurement of CIELab color coordinates; reflectance spectrum, and color strength approaching the depth of the coloration; completed by the calculation of the absorption coefficient, based on the remaining colorant matter in the wastewater effluents (for the dyeing process). Nevertheless, the mordants' influence on the quality of the coloration process was assessed through laundering and lightfastness measured according to European standards for textiles characterization.
The dyeing exhaustion process was also subjected to parameters optimization in terms of the definition of optimum temperature, dyeing liquor ratio, pH, and time, considering the colorants' sensibilities for degrading and processing agents.
A preliminary nearing towards the dyeing wastewater effluent quality assessment supporting the sustainability character of the process was performed through the measurement of basic water characterization indicators as BOD5, COD, metal content, and behavior against biological wastewater treatment. Furthermore, the possible added value of the algae-based colorants was investigated by measuring the antimicrobial and solar protection capacity, enlarging the application prospects of these innovative raw materials for textile applications.
The pigment printing process approached the research of the feasibility of the colorants by employing the conventional synthetic printing paste, completed with the assessment of alternative natural printing paste, considering, at the same time the commercial availability of ingredients.
The obtained results confer a preliminary validation of the suitability of the application of algae-based colorant matter in exhaustion dyeing and pigment printing of cotton and wool, at laboratory scale, with key elements for textile functionalization perspectives, thus paving the path for further investigation which will make possible the upscaling of the processes and industrial use of alternative sustainable materials in the textile industry.
