The pretreatment of a high lignin substrate, coconut coir dust, was studied by chemical
techniques (NaOH solution, ionic liquid, and NaOH followed by ionic liquid) and by a
physical method (subcritical water, SCW). Following substrate pretreatment and a washing
step, structural analyses were performed by scanning electron microscopy, X-ray diffraction
(XRD), and Fourier transform infrared spectroscopy. It was found that all substrates
pretreated by chemical methods had more amorphous structures than the untreated …