A decolorization method for a dyed fiber cloth is provided. The decolorization method for the dyed fiber cloth includes steps of: providing a fiber cloth attached with a dye, extracting the dye attached on the fiber cloth by an extractant, and applying a microwave to evaporate the extractant so as to obtain a dried and decolored fiber cloth.

An ultrasonic drying method used in yarn dyeing and drying machine (200) for drying the washed and dyed wet yarns (300) in the process of dyeing one or more yarns at a desired length in one or more colors in the manufacture of products such as carpet, hand-knit, knitwear in the textile sector, and to an ultrasonic drying system (100) for performing this method, wherein the system contains an Ultrasonic booster (101) which creates sound waves to be transmitted over the wet yarn (300) bundle the excess water of which has been removed by the vacuum unit (209) to remove the water therein before the drying tunnel (210); a horn (103) which is positioned between the ultrasonic booster (101) and the wet yarn (300) to transfer the sound waves generated by the Ultrasonic booster (101) to the wet yarn (300) bundle.

A method for improving the colourfastness of a dyed textile is provided. The method comprises the steps of: conveying a dyed textile along a processing line in a first direction; flowing a fluid from a reservoir through the dyed textile on the processing line in a second directly substantially opposite to the first direction; subsequently removing at least 50% of the applied fluid from the dyed textile; removing contaminants from the fluid; and returning the fluid to the reservoir.