The extraction of natural dye from black tea waste for cotton dyeing application

Natural dyes have been believed to be a promising source to obtain ecological dyes and pigments. In this research, black tea wastes are used in cotton dyeing applications. Black tea wastes contain theaflavin with having substantive dye, so it does not need a high amount of mordant to help the colour hold faster. Thus it will keep the environment friendly. The objectives of this study are to extract theaflavins from tea waste using ultrasound-assisted extraction, to determine the optimum parameters of theaflavins from tea waste and to evaluate the properties of theaflavins from tea waste in cotton dyeing application. The black tea waste was obtained from UMK cafeteria and dried for 2 days under sunlight before dried in the oven at 105°c for 30 minutes. The black tea waste were grinding and extract using two difference solvent which is petroleum ether and ethanol to determine the highest volume of extraction. The extraction has proceeded to ultrasonic-assisted extraction for different volume of solvents (100 ml, 200 ml, 300 ml and 400 ml). The better volume of extraction was 300 ml is proceed to the time extraction (2 hours, 4 hours, 6 hours and 8 hours) before followed to extraction without ultrasonic. Thus, 8 hours of extraction is more effective in extracting black tea waste. For the application of cotton dyeing, it has shown a good dyeing result at 40 °C -50°C with a minimal amount of metal mordant (0.5 %). The experimental data were analyzed using the colorimeter to determine the specification of colours, calibration curve and FTIR to confirmed the components in black tea waste. Results from this work mainly can be applied in the textile industry.