Green hydrotropic extraction technology for delignification of sugarcane bagasse by using alkybenzene sulfonates as hydrotropes

A process for the delignification of sugarcane bagasse using aqueous hydrotropic solutions is investigated. The optimum conditions for the maximum delignification (85%) of bagssse comprise of temperature (388 K), hydrotrope concentration (30% w/w), and bagasse loading (5 wt%) in 240 min. The delignification process was modeled as the extraction of lignin from the solid biomatrix to estimate its diffusivity at 3.43 x 10(-13) m(2)/s and activation energy 16.2 kJ/ mole. The isolated lignin is characterized in detail for surface functionality, nature and morphology (irregular shape, flaky/smooth surface, and amorphous nature), molecular weight (3791 g/mole), phenolic compounds, and thermal stability (633 K), by using, infrared spectrocopy (IR), scanning electron microscopy (SEM), X-ray diffraction (XRD), gel permeation chromatography (GPC), mass spectroscopy, UV spectroscopy, and differential scanning calorimetry analysis (DSC), respectively. The bagasse delignification using aqueous hydrotropic solutions has potential to overcome the problem of breaking of the cellulosic material in the conventional delignification processes. (C) 2013 Elsevier Ltd. All rights reserved.