Valorization of Pelargonium graveolens L’Hér. Hydrodistillation Solid Waste as Natural Dye for Wool Fabrics.

The huge amount of solid waste produced during the hydrodistillation of Pelargonium graveolens L’Hér. is a serious environmental hazard. The aim of this research is to reduce this environmental pollution and to valorize this waste by using its extract as a natural dye. Extracts were used for dyeing wool samples. The dyed fabrics showed shades ranging between brown and beige. By using the Minitab 19 Software, a definitive screening design was used to optimize the dye extraction process. The studied extraction process parameters were pH, temperature, and extraction time. The main studied responses were the color strength and the polyphenol, flavonoid, and condensed tannin contents (mg.g−1). Based on the photochemical study and the UV–vis absorption spectra, it was found that the polyphenol content varies between 4.144 and 7.567 mg.g−1. For the tannin content, the highest value was equal to 120.967 mg.g−1. To optimize the colorant extraction process, the K/S was also measured by the spectrocolorimeter. Process optimum conditions were of 11, 100°C, and 65 min, respectively, for pH, temperature, and extraction time. The optimum K/S value was equal to 115.15. Therefore, the solid waste hydrodistillation of Pelargonium graveolens can be an interesting choice for the natural dyeing of textile fabrics. [ABSTRACT FROM AUTHOR]