Optimization of Extraction and Dyeing Conditions of Natural Dye from Ratanjot Roots Using Ultrasonic Waves

Abstract

The present work involves the optimization of extraction and dyeing recipes to standardize the procedure for natural dye obtained from the roots of Ratanjot (Onosma echiodes) using ultrasonic waves. The resultant dye obtained at optimized extraction conditions was applied on wool fabric to study the effect of temperature, dye concentration, time and dyeing pH. Optical density and colour strength (K/S value) were studied for evaluation of optimum extraction and dyeing conditions. It was observed that extraction and dyeing parameters have significant effect on colour characteristics of dyed wool fabric. The optimized extraction conditions were; dye extraction pH 7, extraction time 60 min and temperature 60ºC while optimized dyeing parameters were; dyeing temperature 60°C, dye concentration 2 g/g, dyeing time 75 min and dyeing pH 5. It was also observed that the optimum dye extraction time and pH is same with the conventional heating method but there is reduction in the temperature (60°C), dyeing time and dye concentration consumption in ultrasonic extraction and dyeing method, thus saves the energy, time and amount of dye requirement. Therefore, ultrasound wave represents a promising method for increasing diffusion of dye by the effect of cavitation, as well as for improving the effectiveness of processes as compare to conventional heating method.