Insight into Low-Temperature One-Step Biopreparation and Natural Dyeing of Cotton as an Environmentally Benign Route

Abstract

The goal of this study is to present an environmentally benign route for cotton fabric and investigate the effect of different pretreatments in natural dyeing. In this context, conventional alkaline scouring, conventional hydrogen peroxide bleaching, low-temperature one-step biopreparation processes, namely enzymatic scouring (alkaline pectinase and alkaline pectinase-neutral cellulase combination) at 55 °C and enzyme-bleaching agent (hydrogen peroxide/sodium percarbonate/sodium perborate)-activator agent (TAED) combinations at 65 °C were applied to 100% cotton knitted fabric. The use of agricultural waste and eco-friendly mordants was preferred in natural dyeing. For this purpose, pretreated fabrics were dyed with the outer green shell of almond fruit extracts and a low amount of 0.4 g/L metal mordants (alum and iron(II) sulfate) in accordance with the simultaneous mordanting method. The dyeing properties of bio- and conventionally prepared cotton fabrics were examined in terms of colorimetric data (K/S, CIELa*b*C*h°) and wash fastness compared with water absorbency, whiteness, weight loss, pectin removal, and type of mordant. Excellent wash fastness values were achieved regardless of the type of pretreatment. Low-temperature one-step biopreparation can be a good substitute for conventional scouring and bleaching processes. Since different results can be achieved, it is essential to determine and evaluate all bioprocess conditions depending on the end-use characteristics of the textile (e.g. whether it will be white or dyed/printed, its color and lightness/darkness) at the laboratory and industrial scale applications.