The dyeing industry is considered one of the most polluting industries. Thus, several researchers have focused on studying the possibilities of natural textile dyeing. The objective of this paper was to optimize the microwave extraction process for Juglans regia bark residues in order to dye acrylic fabrics. Hence, at first, the following extraction conditions were studied: microwave power, pH, extraction duration and concentration of dry mass. Flavonoid and tannin content was measured each time. Moreover, the obtained extracts were used for dyeing acrylic fibers with microwave assistance, and the corresponding color yield (K/S) was measured. Then, the microwave extraction process already developed was optimized; a response surface design was established using Minitab 19 software. The optimal extraction conditions were found to be: microwave power = 850, pH = 3 and extraction time = 4 min. Finally, dyed and undyed acrylic were characterized by infrared (FTIR) spectroscopy in order to distinguish the effect of this natural dye on the external layer of the acrylic fiber.

Juglans regia barks contain a diversity of phenolic compounds. Two of the most important groups of phenolic compounds are tannins, and flavonoids. These latter, possess different antioxidant, anti-inflammatory, and antibacterial properties. This paper explores the usefulness of dyeing cellulosic fabrics, namely cotton, with Juglans regia barks residues extract. The dyeing process proposed was assisted by microwave energy. The impact of the main dyeing conditions (percentage of cationizing agent, pH, dyeing duration, and microwave power) on the color strength (K/S) and the L*, a*, b*, C*, and h* coordinates were studied. Optimization experiments were carried out using a definitive screening type plan (MINITAB 19). It was found that the best conditions to achieve the dyeing of cellulosic fabrics were: a pH of 6.23; a percentage of cationizing agent of 6.5%; a microwave power of 690 W, and a dyeing duration of 4.5 min.

Industrial processes in everyday life need to take into consideration environmental safety. This is the major goal of today's scientific research. Textile research is no exception. This paper illustrates a green process in which indigo is converted into its water-soluble leuco form by using a reducing agent that is ecologically friendly: 3-hydroxybutanone (C4H8O2). The effect of alkalinity and reducing temperature on the reducing power of C4H8O2 has been evaluated in the absence and presence of indigo. The dyeing quality of the modified cotton resultant of the exhaust process is studied. Cotton modification is carried out by using Denitex BC 200% in order to improve the quality of the exhaustion dyeing process. Modified cotton fibres are characterized through a morphology analysis (by using a SEM), Fourier transform infrared spectroscopy and X-ray diffraction analysis. The performances of the indigo dyeing process are evaluated by measuring the redox potentials generated in the medium with and without indigo, dyeing bath exhaustion (E(%)), and colour yield (K/S) of the coloured cotton at 660 nm, brightness index (B(%)) and dyeing fastness of both the untreated and modified cotton fabrics.