Activated carbon from Moringa husks and pods

Moringa oleifera is the most widespread species of the plant family Moringaceae. It is a rapidly growing tree native to the sub-Himalayan regions of north-west India and indigenous to many parts of Africa, South America and Asia, typically reaching a height of 3-4 metres, flowering and fruiting in one year from a 0.3 metre seedling even in poor quality soil (Sutherland, Folkard et al., 1994). It is known by different names around the world (Jahn, 1986), for example in India “Drumstick” or “Horseradish” tree. The tree produces large seed pods which can either be harvested when green for food or left to dry. The dried seeds can be crushed to produce a high quality vegetable oil and the resulting press-cake mixed with water and strained to form a coagulant for water treatment (McConnachie, Mtawali et al., 1994). The residue containing seed husks is currently discarded as waste. The research presented here has been carried out at the University of Edinburgh and the University of Malawi and demonstrates that a simple steam pyrolysis procedure can form high quality microporous activated carbons from both the waste husks of Moringa oleifera and the pods. The work is part of an overall assessment of the viability of the establishment of Moringa oleifera plantations in tropical areas for the benefit of rural communities and is being carried out in collaboration with the Engineering Department, The University of Leicester, U.K.