Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 3/1/2010
Publication Date: 6/27/2010
Citation: Lima, I.M., Coble, C., Klasson, K.T., Uchimiya, S.M. 2010. Effect of nitrogen flow rate on the physical, chemical and adsorptive properties of a broiler manure char (abstract). 2010 US Biochar Initiative Conference, Jun 27-30, 2010, Ames, IA.
Technical Abstract: Thermochemical conversion of biomass involves heating in the absence of oxygen resulting in the decomposition of the organic material. Through this conversion, varying amounts of biochar are produced having diverse degrees of porosity depending on the pyrolysis conditions. Fast pyrolysis processes usually yield chars with negligent porosity while slow pyrolysis generate chars with surface areas that can reach a few hundred square meters per gram. It is possible that some of the gases generated during the slow pyrolysis process might be responsible for the activation of the char during pyrolysis given appropriate time and temperature conditions. These chars can possibly be either used as soil amendments and/or be considered as materials for adsorption applications, particularly for heavy metal removal as an suitable alternative to activated carbons. The objective of this study was to determine the influence of the pyrolysis gases in the final physical, chemical and adsorptive properties of the resulting char. In order to generate different sweeping rates of the pyrolysis gases, the flow rate of nitrogen entering the retort was varied. Pelletized broiler cake was pyrolyzed in a 22 Liter static furnace for 1 hr at 700°C under a stream of nitrogen with flow rates ranging from 100 mL/min to 2,500 mL/min. Resulting chars were characterized for their yield, electron scanning microscopy, surface area, microporosity, pore volume, carbon, hydrogen and oxygen content, elemental analysis, ash content, pH, surface charge and adsorption capacity for copper metal ions. The residence time of pyrolysis gases formed (hydrogen, carbon dioxide, carbon monoxide and hydrocarbons) as affected by the nitrogen sweep rate was found to directly impact the properties of the resulting char in terms of its surface area and surface functionality. Total surface charge and surface function groups in turn were found to relate to the chars ability to adsorb positively charged ions, such as copper.