Natural dyes are not harmful to the environment owing to their biodegradability. For dye application to textiles, salts are necessary as mordant or electrolytes and make an environmental impact. In this paper, the influence of cationization during mercerization to the dyeing of cotton fabric with natural dye from Dactylopius coccus was researched. For this purpose, bleached cotton fabric as well as fabric cationized with Rewin OS was pre-mordanted using iron(II) sulfate heptahydrate (FeSO₄·7H₂O) and dyed with natural cochineal dye with and without electrolyte addition. For the characterization of surface changes after cationization, an electrokinetic analysis on SurPASS was performed and compared to pre-mordanting. For determination of dye exhaustion, the analysis of dye solution was performed on a UV/VIS spectrophotometer Cary 50 Solascreen. Spectrophotometric analysis was performed using a Datacolor 850 spectrophotometer, measuring remission ”until tolerance” and the whiteness degree, color parameters, color depth (K/S), and colorfastness of dyed fabric were calculated. Levelness was determined by visual assessment. Cationized cotton fabrics showed better absorption and colorfastness. Pre-mordanting and cationization showed synergism. The electrolytes improved the process of dye absorption. However, when natural dyeing was performed on cotton fabric cationized during mercerization, similar chromacity, uniform color, and colorfastness were achieved with and without electrolyte, resulting in pure purple hue of cochineal. For achieving a violet hue, pre-mordanting with Fe-salt was needed. Therefore, salt can be reduced or even unnecessary, which makes this process of natural dyeing more environmentally friendly.

Given the global problems of the textile industry, there is increasing interest in revitalizing the use of natural dyes, with an emphasis on cellulose materials. This investigation presents the dyeing of cotton with natural mordant dyes plant origin. The following dye sources were selected: Stems and leaves of goldenrod, willow bark, stems with leaves and flowers of St. John's wort, hawthorn twigs with leaves and oak galls. All selected plants belong to the group of acid-mordant dyes due to their dyeing properties and bind to the fabric by forming a complex with metal salts (mordants). For this reason, the cotton material was treated with potassium aluminium sulphate dodecahydrate KAl(SO4)2 ·12H2O and iron(II) sulphate heptahydrate FeSO4·7H2O. Through the formation of the ligand: cotton fibre - metal ion - natural mordant dye, a wide range of harmonious shades was obtained. The dyes obtained were evaluated by subjective and objective spectrophotometric analysis. In addition, the fastness to laundering and artificial light was tested, which guarantees both the aesthetic and functional quality of the cotton fabrics dyed in this way.

The multidisciplinary project "All colors of Montenegro - dyeing wool with vegetable dyes" combines science, tradition and art and contributes to the preservation and revival of the cultural heritage of wool as well as the use of wool in other areas such as agriculture, construction, etc. By taking up the ideas of the project, an important contribution can be made to reducing pollution and realising the principles of the circular economy, because wool that remains in nature is pollution. The use of indigenous waste or easily renewable plant sources is also insisted upon in the dyeing processes. For dyeing different plants can be used: madder root, black ash leaves, onion skins, walnut leaves. As part of the project, workshops in textile dyeing and traditional felting techniq are organised for students from various disciplines and interdisciplinary lectures are held in the fields of ethnology, philosophy and culture of fashion, biology and chemical textile technology. The focus is on pre-school education and encouraging design students to take an interdisciplinary approach to textiles.