Submitted to: Journal of Agricultural and Food Chemistry
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: October 22, 2010
Publication Date: November 4, 2010
Citation: Uchimiya, M., Wartelle, L.H., Lima, I.M., Klasson, K.T. 2010. Sorption of deisopropylatrazine on broiler litter biochars. Journal of Agricultural and Food Chemistry. 58(23):12350-12356. Interpretive Summary: Thermal conversion of agricultural wastes is a promising on-farm waste-to-energy process necessary for sustainable agriculture. Biochar is one of the products of the thermal conversion process and can be beneficial for crop production when added to soils. In this study, manure, a major agricultural waste, was converted to biochar using different thermal conversion methods. Obtained biochars were tested for the ability to sorb a toxic pollutant resulting from the herbicide use in farming. The results suggest that different thermal conversion methods result in measurably different properties of biochars that can be used to predict the ability of biochars to sorb pollutants. This information will allow us to design biochars having desirable properties for use as soil amendment in sustainable farming.
Technical Abstract: Biochars have received increasing attention in recent years for a large-scale soil amendment to improve soil fertility, immobilize contaminants, and to serve as a recalcitrant carbon stock. Information is currently lacking in factors controlling the sorption capacity of manure-derived biochars. In this study, sorption isotherms for deisopropylatrazine, a stable metabolite of widely applied herbicide atrazine, were obtained in acidic aqueous media (pH 5.5) for broiler litter-derived biochars formed by pyrolysis at 350 and 700 degrees C with and without steam activation at 800 degrees C. An increase in Freundlich distribution coefficient (KF) and isotherm nonlinearity (nF) was observed with pyrolysis temperature and steam-activation, suggesting that the surface area and aromaticity (degree of carbonization) are the factors controlling the sorption capacity of chars at low surface coverage. At high surface coverage, the isotherms became increasingly linear, suggesting sorption on noncarbonized fraction of biochars. In binary-solute experiments, sorption of deisopropylatrazine was significantly diminished by CuII, further suggesting the predominance of surface adsorption mechanism at low surface coverage of biochars.