Electrical and mechanical properties of carbon pellets from acid (HNO3)treated self-adhesive carbon grain from oil palm empty fruit bunch

Factors such as its natural properties, low cost and availability in large quantities as a by-product may give oil palm empty fruit bunches (EFB) a great potential as a candidate precursor for solid carbon products. Self-adhesive carbon grains (SACG) were prepared from EFB by a low temperature pre-carbonization process. Green pellets were prepared from SACG and SACG treated with nitric acid having concentration of 1, 3 and 5 Molar (M). Carbon pellets were produced by carbonization of green pellets up to 1000°C in a nitrogen environment using multi-step heating profile. Measurements on carbon pellets show that the electrical conductivity (σ), hardness (H) and Young's modulus (Y) follow the linear equations σ/[10−3 × (μm Ω)−1] = 0.57M + 4.74, H/[Vickers hardness] = 27M + 148 and Y/[GPa] = 2.6M + 5.0, respectively. This indicates that nitric acid systematically affected the properties of the product. The behavior that σ, H and Y increase linearly with M seems to be associated with the effect of acid treatment on the weight loss, lignocellulosic structure and particle size of the SACG.