Characteristics of oil palm shell biochar and activated carbon prepared at different carbonization times

Palm shells, which are agricultural by-products from palm oil processing, were used to produce low-cost activated carbons. Effect of different carbonization times (1–4 h) on the biochar and activated carbon properties was investigated. The carbonization was carried out at 700°C followed by CO₂ activation. Carbons were characterized using Fourier transform infrared spectroscopy, ultimate analysis, scanning electron microscopy (SEM), proximate analysis and nitrogen adsorption. The proximate analysis of the palm shell showed low moisture content (5.5%), high percentage of volatile matter (70%), average contents of fixed carbon (23%) and ash content (4.28%). Carbonization times (1–4 h) within the range investigated have little influence on the char yield, thermal and chemical properties of the material but had more effect on the textural properties. SEM micrographs revealed that more pore networks and cavities were formed after carbonization and activation of the palm shells. The textural characteristics of the biochars and activated carbon reveal that the pore size is predominantly mesoporous. The properties of the palm shell activated carbon prepared at 700°C for 2 h indicated its ability to be used in volatile organics removal from wastewater and in gas-related adsorption applications.