Degumming of eri silk using ionic liquids and optimization through response surface methodology

The application of imidazolium ionic liquids (ILs) as green material for degumming of silk has been investigated. In this study, degumming of eri silk was attempted using ILs 1-butyl-3-methylimidazolium chloride [BMIM]Cl and 1-butyl-3-methylimidazolium hydrogen sulphate [BMIM]HSO4, synthesized in the laboratory. The molecular structures of the ILs were confirmed by FTIR, 1H-NMR, and 13C-NMR. The thermal properties and solubility were also analysed. Experiments were designed to find out the optimum processing parameters for degumming of eri silk by response surface methodology. The statistical software, Design-Expert 6.0, was used for regression analysis and graphical analysis of the responses obtained by running the set of designed experiments. Analysis of variance was used to estimate the statistical parameters. The polynomial equation of quadratic order was employed to fit the experimental data. The quality and model terms were evaluated by F-test. Three-dimensional surface plots were prepared to study the effect of variables on different responses. The comparison of responses obtained from the experiments of highest desirability with those obtained by alkaline H2O2 (control) indicates that ILs give better results in terms of weight loss and absorbency.