PHYSICAL PRODUCTION OF NIGERIAN RICE HUSK ACTIVATED CARBON: A CASE OF WASTE TO WEALTH

Abstract

The study involves production of activated carbon from Nigerian rice husk waste by physical method. The samples were obtained from milled rice husk dump in Omor, Anambra State. Three treatment stages were carried out involving carbonization of the rice husk, leaching/separation of SiO₂, and activation of the resulting carbonaceous material. Carbonization was done in a Flow Reactor of 5000cm³ capacity at 600^oC. Leaching of carbonized rice husk was done using NaOH followed by precipitation of silica and filtration. Obtained carbonaceous material was activated by physical activation method using water vapor as well as carbon dioxide in a Reactor with external electric heating without access of air. After carbonization, material containing 43.11% C and 25.01 % silicon with a specific surface area of 51.6 m²/g was obtained from material originally containing 39.21% C, 7.01% silica, and specific surface area of about 0.158m²/g . The specific surface area and carbon content of the material increased to 204.5 m2/g and 70.75% by weight respectively while the silicon content decreased to 1.24% by weight after leaching. Activation of carbon material using water vapor at the flow rate of 0.09dm³ /min per 500g of material and at the temperature of 850 °C yields 1346m²/g specific surface area - the best result. Therefore, activated carbon can be effectively produced from Nigerian rice husk by physical method using water vapor which is economical and environmentally friendly method.