Pore structure and surface chemistry of adsorbents obtained by pyrolysis of sewage sludge-derived fertilizer

Terrene(R), a fertilizer product derived from New York City municipal sewag e sludge, was pyrolyzed at various temperatures between 400 and 950 degrees C. The pore structure and surface chemistry of the adsorbent materials obta ined were characterized using nitrogen adsorption, thermal analysis, potent iometric titration and FTIR. The adsorbents contain a high percentage of in organic matter (up to 70%) and only up to 30% carbon. The results show that microporosity is developed within the carbon deposit and at the organic/in organic interface with increasing temperature of heat treatment. An increas e in the pyrolysis temperature also results in significant changes in the s urface chemistry towards the development of basic nitrogen centers. In part icular there was an increase in the pH values of adsorbents' surfaces front 7 to 11. (C) 2001 Elsevier Science Ltd. All rights reserved.