The aim of this study was to select the optimal conditions for the carbonization process followed by surface modification treatment with sodium hydroxide (NaOH) to obtain a highly microporous activated carbon structure derived from palm kernel shells (PKS) and coconut shells (CS). The effects of the carbonization temperature and NaOH concentration on the physiochemical properties, adsorption capability, specific surface area, surface morphology, and surface chemistry of PKS and CS were evaluated in this study. The results show that surface-modified activated carbons presented higher surface area values (CS: 356.87 m2 g−1, PKS: 427.64 m2 g−1), smaller pore size (CS: 2.24 nm, PKS: 1.99 nm), and larger pore volume (CS: 0.34 cm3 g−1, PKS: 0.30 cm3 g−1) than the untreated activated carbon, demonstrating that the NaOH surface modification was efficient enough to improve the surface characteristics of the activated carbon. Moreover, surface modification via 25% NaOH greatly increases the active functional group of activated carbon, thereby directly increasing the adsorption capability of activated carbon (CS: 527.44 mg g−1, PKS: 627.03 mg g−1). By applying the NaOH post-treatment as the ultimate surface modification technique to the activated carbon derived from PKS and CS, a highly microporous structure was produced.

An integrated and feasible approach was proposed using the underutilized grass fibre (stem) derived from Napier grass and sugarcane for paper production in this study. To enhance paper strength, pre-hydrolysis and beating techniques have been used to improve the chemical pulps and mechanical pulping process, respectively. Napier grass and sugarcane are promising non-wood sources for pulp production, owing to their high cellulose and low lignin and extractive content. With the additional mild alkaline pre-treatment to the mechanical pulping process, the lignin content was greatly reduced. The results reveal that the mechanical pulping with alkaline pre-treatment may indeed potentially replace the most prevalent pulping process (chemical pulping). As evidenced by the paper strength properties, mechanical pulping is far more suitable for grass-type biomass, particularly Napier grass, which had a folding endurance capability five times greater than chemical pulping. Furthermore, the remaining high hemicellulose content from mechanical pulping contributed to a high pulp yield, while also facilitating the fibrillation on the sugarcane’s laboratory paper handsheet. The findings also demonstrated that the additional beating process from chemical pulping causes the fibres to be drawn toward each other, resulting in a more robust fibre network that contributes to good paper strength. Consequently, this work sheds new light on the development of advanced paper derived from grass fibre.

The development of low-environmental-impact technologies for the elimination of biological damage is one of the vital goals of the wood protection industry. The possibility of utilizing pyroligneous acid as a wood preservative can be a great solution to extend the application of the currently fast-growing timber species, which has lower natural durability against biological damage. In this study, the effectiveness of pyroligneous acid as a wood preservative was evaluated by impregnating rubberwood with pyroligneous acid using vacuum-pressure treatment, and the treated woods were exposed to mould fungi, wood-decay fungi and termite attacks under laboratory conditions. Pyroligneous acids produced from rubberwood (RWPA) and oil palm trunk (OPTPA) at different pyrolysis temperatures were evaluated. To fully understand the effectiveness of pyroligneous acids as wood preservatives, different concentrations of pyroligneous acids were impregnated into rubberwood. Concentrations of 50% RWPA and 30% OPTPA were sufficient against mould and decay fungi on rubberwood. Rubberwood impregnated with pyroligneous acid acted as a slow-acting toxic bait to cause a high termite mortality rate due to toxic feeding and does not serve as a good repellent to prevent termites from feeding on the wood. In general, OPTPA has better biological durability compared to RWPA.

As the products made from wood–plastic composites (WPCs) become more sophisticated and required more detail profiles, the injection moulding processing method with wood pulp as the reinforcing material is the answer to cater to the rapid change and demands of composite products. The general objective of this study was to study the effects of the material formulation, as well as the injection moulding process parameters, on the properties of a polypropylene composite reinforced with chemi-thermomechanical pulp from oil palm trunks (PP/OPTP composite) via the injection moulding process. The PP/OPTP composite with a material formulation of 70% pulp/26% PP/4% Exxelor PO produced using injection moulding at 80 °C as the mould temperature and with 50 tonnes of injection pressure exhibited the highest physical and mechanical properties. The increment loading of pulp increased the water absorption capacity of the composite. Higher loading of the coupling agent effectively reduced the water absorption capacity and increased the flexural strength of the composite. The increase in mould temperature from unheated to 80 °C prevented excessive heat loss of the flowing material, which enabled the molten material to flow better and filled up all cavities in the mould. The increased injection pressure slightly improved the physical properties of the composite, but the effect on the mechanical properties was insignificant. For the future development of WPCs, further studies should be focused on the viscosity behaviour, as a greater understanding of the processing parameters’ effects on the PP/OPTP’s viscosity behaviour will lead to improved product design and enable great potential usage of WPCs.

Granular activated carbon (GAC) and powdered activated carbon (PAC) are the two most common forms of activated carbon with varying particle size range. The goal of this study was to analyze the key factors (particle size and activation temperature) affecting the surface characteristics of GAC and PAC derived from palm kernel shell (PKS). The surface morphology suggested that the pore network in PKS-PAC is more developed than that in PKS-GAC owing to the presence of a micropore structure when prepared at lower activation temperatures. This study also demonstrated that activation performed on different PKS particle size range influenced the mesopore domain of the activated carbon produced. The PKS-GAC was found to have more mesopores than PKS-PAC, which made it more reliable for dye adsorption in water treatment. Overall, this study demonstrated that applying different particle size range of PKS during the activation process can have a significant influence on the surface characteristics, thus having a direct impact on the application of activated carbon. An accurate particle size range will ensure that the most cost-effective activated carbon is selected to achieve the desired performance objectives.