STRUCTURAL CHANGES DURING BIOCHAR FORMATION AS ELUCIDATED BY 2-D CORRELATION SPECTROSCOPY: IMPLICATIONS FOR SORPTION CHARACTERISTICS AND ENVIRONMENTAL STABILITY

Properties of biochars, and subsequently how they function in the environment, are determined largely by source material chemistry and biochar formation conditions. We postulated that for a given source material, biochar properties formed along a perturbation gradient are predictable and therefore allows for the development of structure-sorption and structure-stability relationships. To test our hypothesis we used 2D-correlation spectroscopy to study changes in the functional group chemistry of plant-derived biochars formed along a temperature gradient (consistent with natural vegetation fires). Three taxonomically different plant materials were studied. Our results showed a strong link between changes in functional group chemistry, cation exchange capacity and thermal degradability. Implications of these relationships on the role of biochars in the context of biogeochemical cycling of contaminants/nutrients and carbon sequestration in fire-impacted or ammended soils will also be discussed.