Production and characterization of activated carbon from bituminous Nasarawa coal

Abstract

Some varieties of coals, lignocellulosic materials like wood, coconut husk and various agricultural wastes can be used for production of activated carbon (AC). This study looks into the production of an AC from bituminous Lafia-Obi Nasarawa coal by chemical activation with phosphoric acid. The effects of activation temperature and time on the textural characteristics were investigated. A preliminary proximate analysis put the fixed carbon content of the raw coal sample at 63.6%, thereby effectively putting the coal within the rank of bituminous coal. The coal sample was activated with phosphoric acid in a coal to acid mass ratio of 1:4. As carbonization temperatures were varied between 550 and 700°C, and carbonization times of 2 and 3 hours, the effects of these two process variables on BET surface area, DR micropore volume and HK pore size were investigated. The AC sample produced at 550°C and 2 hours residence time was found to possess a BET surface area of 331.3.2 m²/g, DR micropore volume of 0.125 cm³/g and HK pore size of 9.237 Å, while AC sample produced at 700°C and 3 hours residence time was found to possess a BET surface area of 596.2 m²/g, DR micropore volume of 0.173 cm³/g and HK pore size of 9.435 Å. When using the water adsorption technique, the Langmuir and BET surface areas were 3855 m²/g and 748.3 m²/g respectively. These values are all within the ranges of most commercial activated carbon.