Green algae, Cladophora glomerata L.–based natural colorants: dyeing optimization and mordanting for textile processing

Exploration of algal-based natural dye sources, one of the pre-requisites of sustainable and eco-friendly textile processing, had been among the neglected areas of phycological research. The current investigation was carried out to explore the natural dye-yielding potential of a green algal species, Cladophora glomerata, and optimization of conditions for cotton fabrics, as an attempt to provide a cheap alternative of hazardous synthetic chemicals. A number of media were tested to extract the natural colorant from Cladophora along with metal salts as mordants. The results indicated that 2% NaOH was the best medium for natural colorant extraction from Cladophora powder, compared with all other media used in the study. Experiments of dyeing variable optimization showed that dyeing of cotton fabric with Cladophora extract for 45 min at 75 °C produced excellent shades. Four percent NaCl as exhausting agent produced good color shades on Cladophora powder–treated cotton fabric in dyeing medium having pH 9.0. The cotton fabric dyed with Cladophora showed light-green color shade. Different other shades (creamy, yellow, brown, etc.) of Cladophora powder–treated cotton fabric were obtained after mordant application. Among the four chemical mordants, tannic acid produced excellent color depth at given optimum dyeing conditions.