Greener natural dyeing pathway using a by-product of olive oil; prina and biomordants

Abstract

The current study is the first report of using biomordants with prina extract as a possible substitute for environmentally unfavourable metallic mordants. As a part of sustainable and cleaner production approach, eco-friendly natural dyeing conditions were presented in terms of cost and consumption efficiencies. A novel and renewable natural dye source prina is an essential by-product of olive oil production. This biomass was valorized in wool dyeing in conjunction with biomordants namely powder of iris germanica (I. Versicolor), valex (acorn of Quercus ithaburensis ssp.macrolepis), pomegranate (Punica granatum L.) rind, rosemary (Rosmarinus officinalis), and thuja (thuja orientalis). Their color coordinates and fastness properties were compared and assessed versus metallic mordants. Prina extract itself without mordant has a fair light fastness of 3 and an excellent washing fastness of 4-5 both for color change and bleeding. Valex, pomegranate rind, iris, rosemary, and thuja leaves were proposed as promising alternatives to alum, iron II sulfate, copper II sulfate, stannous chloride, and potassium dichromate. Biomordants generated significant color yield increment and exhibited equivalent fastness properties to metallic mordants. Water, energy, dye, chemical cost, and consumption of natural and synthetic dyeings on the basis of mill conditions were also calculated and compared mutually. Total recipe cost and chemicals/auxiliary consumption of natural dyeing are on average significantly less than with synthetic dyeing. Considerable savings are possible with natural dyeing, especially one-bath, in terms of cost, time, and consumption.