Recycling colored silk fibroin from silk waste for versatile applications in dyeing, adsorbing and printing

Abstract

Colored textile waste has been a concern due to the complexity of textile recycling and environmental issues in waste landfills. This study creatively repurposed dyed silk waste for versatile applications in fabric dyeing, water cleaning, and cotton printing. First, dyed silk waste was reclaimed into colored silk fibroin (CSF) for wool dyeing at 75 °C and pH 2.5, achieving 76% dye reuse. After further recycling the dye effluent, over 63% silk fibroin (SF) was recovered, and the remaining water was suitable for reuse in CSF dyeing. Second, the recycled SF could be pulverized into powders as adsorbents, featuring a maximum adsorption capacity of 82.79 mg/g for acid dyes. Finally, wastewater-adsorbed SF was used as pigments for cotton printing with good washing and crocking fastness. In this work, a waste recycling strategy is proposed to promote the resource conservation and waste valorization by producing new colored fabrics and lowering dye contamination. Graphical abstract: [Figure not available: see fulltext.]