Sugarcane bagasse cellulose fibres and their hydrous niobium phosphate composites: synthesis and characterization by XPS, XRD and SEM

Abstract

Cellulose fibres obtained from sugarcane bagasse were submitted to a purification process, which consisted of an acid hydrolysis for elimination of the major part of lignin and hemicellulose. This was followed by a delignification process carried out in two steps to yield crude cellulose (CCell) fibres in the first one and with a subsequent bleaching in order to yield bleached cellulose fibres (BCell). Composites of crude and bleached cellulose fibres with hydrous niobium phosphate, cell/NbOPO4 center dot nH(2)O, were subsequently synthesized. Scanning electron microscopy, X-ray photoelectron spectroscopy and X-ray diffraction characterization of the obtained materials showed CCell/NbOPO4 center dot nH(2)O and BCell/NbOPO4 center dot nH(2)O are real composites. The nature of the cellulose (CCell or BCell) has an important role on the composites obtained, namely on the niobium salt composition at the composite surface. The synthesis of membranes of both cellulose and mixed matrix cellulose/NbOPO4 center dot nH(2)O was only possible when the bleached cellulose was used.