Adsorption behavior of anthraquinones in deep eutectic solvent on polyester fiber and its application

Deep eutectic solvents (DESs can be used to facilitate the adsorption of anthraquinone dyes into polyester fabrics (PETFs) in facile conditions. The adsorption mechanism was investigated through a systematic characterisation study using methods including 1H nuclear magnetic resonance spectroscopy, ultraviolet–visible spectroscopy, scanning electron microscopy, Fourier transform infrared spectroscopy, thermogravimetric analysis, water contact angle analysis, and tensile strength tests. It was found that anthraquinone dyes have different types of interactions with DESs, and that the adsorption and dyeing of PETF can be achieved only when the interactions between PETF and anthraquinones were stronger than those between the PETF and DESs. Additionally, the type of DES, hydrogen bond acceptor–hydrogen bond donor ratio, dye concentration, dyeing temperature, and dyeing time affect the adsorption and dyeing efficiency. In summary, PETF was successfully dyed with DES as a solvent, and the presence of DES did not destroy the PETF or significantly change its properties. Meanwhile, anthraquinone dyes affect the properties of PETF by forming non-covalent interactions. This study provides insights into problems encountered with adsorption and separation of target compounds in DESs, and provides the textile industry with a potentially much greener alternative that can reduce energy consumption and pollutant emissions, and avoid using toxic solvents for dyeing fabrics using DESs.