Characteristics of Wood Sponge from Sengon (<i>Falcataria moluccana</i>) Wood Manufacturing through a Multistage Delignification Process

Adsorbents with three-dimensional porous structures have gained widespread attention due to their unique characteristics, including a large surface area, high porosity, and excellent absorption capacity. One of the products is the wood sponge. The key to successfully producing wood sponges lies in an optimal multistage delignification process, which is particularly influenced by wood species, solvent, time, and temperature. The aim of this research was to analyze the characteristics of wood sponge derived from sengon wood (Falcataria moluccana Miq.) after multistage delignification. The process involved delignification using NaOH and Na2SO3 solutions at 100°C for 8, 9 and 10 h, followed by further delignification in H2O2 solution at 100°C for 1, 2, 3, and 4 h. The samples were then frozen at 20°C for 24 h and freeze-dried at 53°C for 48 h. The results showed that wood sponges treated at 100°C exhibited lower density, larger pore diameters, brighter color, and superior absorption capacity compared to untreated wood and sponges treated at room temperature for 24 h. FTIR analysis confirmed a decrease in wavelength between 1032–1035 cm−1, indicating the degradation of hemicellulose and lignin. XRD analysis revealed that crystallinity increased as amorphous content decreased with prolonged delignification. The wood sponges demonstrated good porosity, with an absorption capacity ranging from 0.65 to 2.24 g/g. The optimal treatment suggested in this research was multistage delignification using NaOH and Na2SO3 solution for 10 h, followed by a 1 h treatment with H2O2 solution.