The effect of alkaline concentration in the alkaline delignification-assisted sonication on sengon wood

Abstract

Sengon wood is classified as soft wood because of its characteristics and is widely used in Indonesia. Utilization of Sengon wood produces wood dust that can still be used because of its high cellulose content. Sengon wood contains 41.17% cellulose, 22.26% hemicellulose and 17.51% lignin. In this study, cellulose extraction was carried out using alkaline delignification-assisted ultrasound methods. The effect of alkaline concentration was studied to obtain cellulose with good characteristics. The delignification process was carried out by mixing sawdust with NaOH solution (1:30 w/v). The process was carried out at 40 °C for 30 minutes with various concentrations of NaOH (0.2 M - 0.7 M). Process results were analyzed using Chesson analysis, X-ray Diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR) and Scanning electron microscopy (SEM). Based on the data, the highest decreasing of hemicellulose and lignin composition was achieved at the lowest concentration of NaOH (0,2 M). Morphologically, it appears that alkaline-delignification-assisted ultrasound is able to expand contact area of NaOH solution and tear the surface structure.