Utilization of charcoal in environmental protection

The microstructures of wood and rice hull charcoal were assessed against a commercial activated carbon using a X-ray diffractometer and scanning electron microscope. The adsorption kinetics of nitrogen contained in water by wood charcoal and activated carbon was further studied, and the effects of rice hull charcoal on soil pH and plant growth were also investigated. X ray diffraction patterns indicated that wood charcoal, rice hull charcoal and activated carbon could be considered as aggregates of fine graphite crystalline. The wood charcoal and activated carbon contained more fine (on square level) and large (mum level) pores than that the rice hull charcoal had. Nitrogen (11 and 32 mg) was removed from a test solution of potassium nitrate by 1 g of wood charcoal and activated carbon, respectively. An adsorption rate constant of 0.118 min(-1) for the wood charcoal, and 0.165 min(-1) for the activated carbon were obtained. However, there was no noticeable adsorption of nitrogen from the solutions of ammonium chloride by the wood charcoal and activated carbon. The soil acidity and plant growth could be substantially improved by the application of 25-33% rice hull charcoal together with compost in culture medium.