Pore structure and adsorption characteristics of steam pyrolysis carbons from Moringa oleifera Original Research Article

A series of activated carbons has been prepared from the waste seed husks of the tropical multi-purpose tree Moringa oleifera, using a single-stage steam pyrolysis activation. Carbons were characterised by N2 adsorption, CHN analysis and scanning electron microscopy. Nitrogen adsorption isotherms were analysed by the BET, t-plot and Horváth and Kawazoe methods. All the carbons were microporous, with those activated at 750 °C for 120 minutes (750120) and 800 °C for 30 or 60 minutes having the highest BET surface areas, of 730, 713 and 774 m2 g−1, respectively. A simple acid rinse of the 800 °C/30 minutes carbon increased the surface area to 932m2g−1. The 800/60 carbon had the highest mesopore and macropore surface area, 135.7 m2g−1, compared to 92.7m2g−1 for the 80030 carbon. Scanning electron micrographs of the 80030 carbon showed a lignocellulosic macropore structure, cleaned by the steam pyrolysis.