Activated carbons can be produced from different precursors, including coals of different ranks, and lignocellulosic materials, by physical or chemical activation processes. The objective of this paper is to characterize oil‐palm shells, as a biomass byproduct from palm‐oil mills which were converted into activated carbons by nitrogen pyrolysis followed by CO₂ activation. The effects of no holding peak pyrolysis temperature on the physical characteristics of the activated carbons are studied. The BET surface area of the activated carbon is investigated using N₂ adsorption at 77 K with selected temperatures of 500, 600, and 700°C. These pyrolysis conditions for preparing the activated carbons are found to yield higher BET surface area at a pyrolysis temperature of 700°C compared to selected commercial activated carbon. The activated carbons thus result in well‐developed porosities and predominantly microporosities. By using this activation method, significant improvement can be obtained in the surface characteristics of the activated carbons. Thus this study shows that the preparation time can be shortened while better results of activated carbon can be produced.

Additive manufacturing (AM) of Natural Fiber-Reinforced Composites through Fused Deposition Modeling is receiving much attention in recent years. AM is very appealing for complex shape structures that can be inconvenient to produce by other methods. In this study, the acoustic panel made from polylactic acid reinforced with wood fiber composite was 3D printed by varying its thickness and infill density. The sound absorption coefficient was measured using an impedance tube. The thin panel with back air gap was found to absorb sound at mid-frequency range resembling the Helmholtz resonator. The absorption performance for the thick panel can be controlled by controlling the infill density of the panel. Customizing the acoustic absorption is therefore possible for panels from biodegradable materials by AM.