Characterization of copper binding to biochar-derived dissolved organic matter: Effects of pyrolysis temperature and natural wetland plants

Characterization of the biochar-derived dissolved organic matter (BDOM) is essential to understanding the environmental efficacy of biochar and the behavior of heavy metals. In this study, the binding properties of BDOM derived from different pyrolysis temperatures, wetland plants, and plant organs with Cu was investigated based on a multi-analytical approach. In general, the pyrolysis temperature exhibited a more significant impact on both the spectral characteristics of BDOM and Cu binding behavior than those of the feedstocks. With the pyrolysis temperature increased, the dissolved organic carbon, aromaticity, and fluorescence substance of BDOM decreased and the structure became more condensed. Humic-and tryptophan-like substance was more suscep-tible to the addition of Cu for BDOM pyrolyzed at 300 degrees C and 500 degrees C, respectively. In addition, the more tyrosine-like substance is involved in Cu binding at higher pyrolysis temperature (500 degrees C). However, the fluvic-like substance occurred preferentially with Cu than the other fluorophores. Moreover, the higher binding capacity for Cu was exhibited by the humic-like substance and by BDOM derived from the higher pyrolysis temperature and the lower elevation plants with the corresponding average stability constants (log KM) of 5.58, 5.36, and 5.16.