Parametric study on microwave-assisted extraction of runo (Miscanthus sinensis Andersson) dye and its application to paper and cotton fabric
Ivan Anthony P. Pinzon, Ramon A. Razal, Rosalie C. Mendoza, Rowena B. Carpio, Ramon Christian Eusebio
Abstract
The study was designed to devise a high-yielding, microwave-assisted extraction of the colored material from the core tissue of runo (Miscanthus sinensis Andersson) stem. Soxhlet extraction of M. sinensis core tissue gave yields ranging from 1.04 % with dichloromethane to 11.91 % from 1:1 ethanol-water mixture. Folin-Ciocalteau tests showed that the extracts were primarily flavonoid compounds, accounting for 66.05 ppm of the total 1:1 ethanol-water extractable material. Initial application trials of the ethanol, ethyl acetate, and ethanol-water extracts followed by color fastness tests showed poor retention on both paper and cotton fabric, suggesting the need for a mordant. Subsequent trials with aluminum acetate as mordant showed greatly improved binding of the ethanol-water extracted dye onto the cotton fabric following wash, rubbing, and light fastness tests. A two-level, full factorial model extraction procedure to determine the effects of extraction time (15 s – 90 s), solvent volume (50 mL – 150 mL), and microwave power level (90 W – 540 W) was done for all solvents used. All three factors had a significant effect on the dye extraction yield, along with the interactions between duration-power level and volume-power level. The highest yield for microwave assisted extraction was at 15 s −150 mL – 540 W setting. Results suggest that microwave extraction can potentially produce dye extracts from M. sinensis core material with a faster throughput than simple soaking and Soxhlet extraction.