Utilization of waste protein from Antarctic krill oil production and natural dye to impart durable UV-properties to cotton textiles

Abstract

Cleaner production in the textile industry may be realized by replacing certain synthetic substances with natural materials, especially those that are industrial by-products, which offer the added benefit of increasing the value of the textiles. Since natural materials generally pose a low risk to both the human health and the environment owing to their biodegradability, the wastewater released from their manufacturing processes is less polluting, and therefore, it requires less resources and energy for treatment compared to wastewater loaded with synthetic substances. Herein, we report the use of a protein by-product recovered from the oil extraction process of Antarctic krill (Euphausia superba) to replace traditional mordanting agents in the dyeing of cotton with tannin-rich natural dye extracted from the bark of Xylocarpus granatum. Antarctic krill protein pretreatment successfully improved the dyeability of the fabrics through the formation of insoluble complexes between the protein and tannin. The color parameters of the dyed samples were measured based on the CIE L*a*b* system. The obtained reddish-brown fabrics exhibited mostly good to excellent color fastness ratings in response to washing and other wet treatments. They also displayed durable UV protection properties, with the UPF rating reaching the maximum (50+) level, despite being washed for 50 cycles. Both the Antarctic krill protein and tannin contributed to improved UV protection efficiency due to the presence of UV-absorbing moieties and slight changes in the resulting fabric thickness and cover factor.