Palm oil has been the world's main source of oil and fats since 2004, producing over 45 million tonnes in 2009. Malaysia alone has over 4·5 million hectares planted with oil palm and, based on common practice, ∼300 palm fronds are pruned per hectare per year. This agricultural waste is currently either being used as roughage feed or, more frequently, being left between rows of palm trees to prevent soil erosion, or for nutrient recycling purposes. This paper proposes an alternative use for palm frond as a source of biochar. A traditional method commonly use by gardeners in Malaysia to improve soil fertility was used to produce the biochar. A shallow earth pit was dug in the ground for the carbonisation process. The process is described and the impact of carbonisation on the earth wall is analysed and presented. The process was later re-assessed by using TGA-FTIR. Most of the hemicelluloses had fully disintegrated, but the depolymerisation of the cellulose was still incomplete at the carbonisation temperature. Most of the lignin aromatic structure was still present in the biochar. The carbonisation process was repeated in the laboratory and biochar was characterised by using BET, SEM and FTIR. An adsorption isotherm study was conducted and the experimental data were fitted to the Langmuir model. The model predicted Pb2+ adsorption rates of 83·3 mg/g, Cu2+ 41·4 mg/g, Ni2+ 13·0 mg/g and Zn2+ 19·7 mg/g.

This study is concerned with the relationship between carbonisation conditions and properties of the resultant bagasse char, and the challenging proposal for the use of fine bagasse char particles as high-performance solar light collectors. Bagasse char was obtained by carbonising raw bagasse at temperatures of 200–900°C for three hours in nitrogen (N2) gas. Characterisation of the resultant bagasse char was performed by elemental analysis (EA), scanning electric microscope (SEM) observation, estimation of colour, nominal bulk density and evaluation of specific surface area and pore structure by N2 gas absorption/desorption. The most typical property of the resultant bagasse char is its unique pore structure, which is clear in SEM observation. The largest specific surface area of bagasse char in this study was about 600 m2/g, which is as large as commercial activated carbon materials. Macro-, meso- and micro-porous structures in the bagasse char induce many important characteristics, such as increased hydrophilicity, very low bulk density and excellent light absorption and accumulation. We also suggest the use of bagasse char as an excellent heat insulation material. The energy used for air conditioning in a private house or office building can be decreased by more than 50–60% by use of this insulator on the roof or walls.