Pilot scale water free dyeing of pure cotton under supercritical carbon dioxide

Organoclay-assisted disperse dyeing of polypropylene nanocomposite fabrics in supercritical carbon dioxide

Dyeing using supercritical carbon dioxide (SC-CO2) is carried out on the polypropylene (PP) nanocomposite fabrics with model disperse dye compared with their regular fabric at various dyeing temperatures and pressures. The results are compared with those obtained in aqueous dyeing method. The PP nanocompsite fabrics dyed in SC-CO2 medium exhibited higher colour strength (K/S) values compared with their PP regular fabric. The PP nanocompsite fabrics and their regular fabric dyed in SC-CO2 medium have higher K/S values than those dyed in aqueous medium. The color coordinates of all PP fabrics dyed in SC-CO2 and aqueous medium were positive with respect to a* and b* coordinates depending on the disperse red dye uptake. The PP nanocomposite fabrics dyed in SC-CO2 and aqueous medium exhibited higher antibacterial properties than their regular fabrics. All PP fabrics dyed in SC-CO2 and aqueous medium present very good washing, perspiration and light fastness.

Critical Review on Sustainability in Denim: A Step toward Sustainable Production and Consumption of Denim

The exponential development in knowledge on the health and environmental concerns linked to conventional denim processing is directly responsible for the continuous increase in demand for the exploitation of sustainable denim. Research is essential to explore alternative methods to reduce the environmental impact caused by these industries. This review examines the many sustainable ways to produce denim, keeping in mind the problems that the denim industry is now facing in finding alternatives to conventional manufacturing practices. The most current advancements in environmentally friendly dyeing techniques for denim have been extensively discussed. These processes include the production of indigo from bacteria as well as different dyeing processes, such as digital spray, microbially assisted dyeing, and foam dyeing denim with indigo. In addition, this review covers the many environmentally friendly finishing methods for denim garments, such as ozone fading, e-flow, enzyme-based bleaching, water, laser fading, and so on. Finally, it is described how the chemical and mechanical processes used to finish denim might affect the amount of microplastics and microfibers released from the denim garment during domestic washing. As a result, the content presented in this review aims to address the importance of sustainable denim processing, that is, something that can be rethought, reevaluated, renewed, and restructured within the scope of conventional denim processes, while taking eco-responsible solutions for increased environmental sustainability into account.

Optimization of Extraction of Natural Antimicrobial Pigments Using Supercritical Fluids: A Review

It has become increasingly popular to replace chemically synthesized compounds with natural counterparts mostly found in natural sources, such as natural pigments. The conventional extraction processes for these compounds are limited by the toxicity and flammability of the solvents. To obtain pure extracts, it is always a longer process that requires several steps. Supercritical fluid extraction (SFE) is a cutting-edge green technology that is continuously increasing and expanding its fields of application, with benefits such as no waste produced, shorter extraction time, automation, and lower solvent consumption. The SFE of natural pigments has high potential in food, textiles, cosmetics, and pharmaceuticals; there are a number of other applications that can benefit from the SFE technique of natural pigments. The pigments that are extracted via SFE have a high potential for application and sustainability because of their biological and antimicrobial properties as well as low environmental risk. This review provides an update on the SFE technique, specifically as it pertains to the optimization of health-promoting pigments. This review focuses on antimicrobial pigments and the high efficiency of SFE in extracting pure antimicrobial pigments. In addition, the optimal conditions, biological activities, and possible applications of each category are explained.