Pyrolysis Temperature-Dependent Changes in the Characteristics of Biochar-Borne Dissolved Organic Matter and Its...

The dissolved organic matter (DOM) samples from biochars produced from Jerusalem artichoke stalks by pyrolysis at 300, 500, and 700 °C were characterized using a combination of spectroscopic techniques. Additionally, the binding affinities (long K_M) and the complexation capacities (C_L) of the DOM samples with Cu(II) were calculated to assess their Cu binding properties. The biochar-borne DOM contained mainly humic-like components (C1-C3) with a small amount of a protein-like component (C4). As the charring temperature increased, the concentrations of released DOM decreased. The low temperature biochar-borne DOM was found to have more carboxyl groups than its high temperature counterparts, and thus it had larger C_L values. In contrast, the high temperature biochar-borne DOM had larger long K_M values. Low temperature biochars, if applied in a large quantity, would alter copper mobility in the environment because of their high DOM contents and large copper binding capacities.