The present study was conducted to study the physico-chemical characteristics (proximate and ultimate analyses, particle size distribution, energy content and ash analyses) and investigate the combustion behaviour of empty fruit bunch (EFB)-derived biochar (EFBC) as potential solid fuel for power generation.

In this work, to fabricate a novel composite consisting of chitosan/poly-lactic acid doped with graphene oxide (CS/PLA-GO), composites were prepared via solution blending method to create various compositions of CS and PLA (90/10, 70/30 and 50/50CS/PLA-GO). Graphene oxide (GO) was added into a PLA solution prior to blending it with chitosan (CS). The surface morphology and structural properties of synthesized composites were characterized using FT-IR, SEM and XRD analysis. The performances of synthesized composites on thermal strength, mechanical strength, water absorption, and microbial activity were also evaluated through standard testing methods. The morphology of 70/30CS/PLA-GO became smoother with the addition of GO due to enhanced interfacial adhesion between CS, PLA and GO. The presence of GO has also improved the miscibility of CS and PLA and has superior properties compared to CS/PLA composites. Moreover, the addition of GO has boosted the thermal stability of the composite, with a significant enhancement of Td and Tg. The highest Td and Tg were accomplished at 389 °C and 76.88 °C, respectively, for the 70/30CS/PLA-GO composite in comparison to the CS and PLA that recorded Td at 272 °C and 325 °C and Tg at 61 °C and 60 °C, respectively. In addition, as reinforcement, GO provided a significant influence on the tensile strength of composites where the tensile modulus showed remarkable improvement compared to pure CS and CS/PLA composites. Furthermore, CS/PLA-GO composites showed excellent water-barrier properties. Among other compositions, 70/30CS/PLA revealed the greatest decrement in water absorption. From the antibacterial results, it was observed that 90/10CS/PLA-GO and 70/30CS/PLA-GO showed an inhibitory effect and had wide inhibition zones which were 8.0 and 8.5 mm, respectively, against bacteria Bacillus Subtillis B29.

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Biodiesel obtained from palm oil over an environmentally friendly catalyst is highlydesirable. For that matter, dolomite, a natural material was used as a catalyst in this work, and this included potassium oxide (K2O)-doped dolomite, 5 wt% K/D, 10 wt% K/D, 15 wt% K/D, and 20 wt% K/D. X-ray diffraction analysis of dolomite revealed the CaO and MgO phases with high crystallinity, in which intensity reduced after doped with varying concentrations of K2O. When the catalysts were evaluated, the K2O-doped dolomite exhibited a better catalytic activity for palm oil transesterification. In the presence of K2O, the methyl ester reached 98.7%, with the highest being displayed by 15 wt% K/D as compared to 87% over dolomite at reaction temperature of 60 °C, 12:1 methanol to palm oil ratio, 1 wt% catalyst amount and 1 h reaction time. SEM revealed that as more K2O was doped on dolomite, the particles became more agglomerated, with a reduced BET surface area of 1.3 m2/g in 20 wt% K/D as opposed to homogeneously small-sized MgO and CaO particles in dolomite with a high BET surface area of 19.0 m2/g. However, the high activity of the doped catalyst was dictated by the high amount of basic site, as evidenced in TPD-CO2 which showed an increase in the capacity of the basic site with an increased amount of K2O. The catalyst was also reusable up to six times with a negligible decrease in activity due to K+ leaching.

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