Dissolved organic matter released from rice straw and straw biochar: Contrasting molecular composition and lead binding behaviors

It remains debatable whether carbonized straw reapplying is a better solution than direct straw reapplying. Comparison of the characteristics and complexation behaviors of dissolved organic matter (DOM) derived from straw (ST) and biochar (BC) may offer new insights, but little current information e...

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Published in:The Science of the total environment 2020-10, Vol.739, p.140378-140378, Article 140378
Main Authors: Huang, Mei, Li, Zhongwu, Chen, Ming, Wen, Jiajun, Luo, Ninglin, Xu, Weihua, Ding, Xiang, Xing, Wenle
Format: Article
Language:English
Subjects:
Biochar
Complexation modeling
Dissolved organic matter
FTICR mass spectrometry
Parallel factor
Rice straw
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Summary:It remains debatable whether carbonized straw reapplying is a better solution than direct straw reapplying. Comparison of the characteristics and complexation behaviors of dissolved organic matter (DOM) derived from straw (ST) and biochar (BC) may offer new insights, but little current information exists. Herein, DOM samples were characterized by Fourier transform ion cyclotron resonance mass spectrometry (FTICR-MS), revealing that the molecular weight and condensed aromatic components of BCDOM (457.70 Da and 71.16%, respectively) were higher than those of STDOM (433.48 Da and 3.13%, respectively). In particular, the N-containing compounds of BCDOM was more aromatic than STDOM. By combining spectroscopic techniques, complexation modeling, and chemometric analysis, BCDOM was shown to exhibit higher binding parameters (log KM) and more binding sites for Pb than STDOM. Noteworthily, the two binding sites, aromatic NO and aromatic NO2, existed only in the interaction of BCDOM with Pb. Furthermore, while phenol-OH displayed the fastest response to Pb in both STDOM and BCDOM, the binding sequences were not exactly the same. These differences may be related to the variations in the aromaticity and N-containing structures of DOM detected by FTICR-MS. These findings have implications on the stewardship of straw- and biochar-amended soil. [Display omitted] •Dissolved organic matter (DOM) derived from rice straw (ST) contains 73.46% lignin.•DOM derived from biochar (BC) was mainly composed of condensed aromatics (71.16%).•BCDOM exhibited higher Pb-binding capacities than STDOM.•BCDOM contained two extra Pb-binding sites, aromatic NO and aromatic NO2.•Different aromaticity and N-structure may explain Pb-binding differences of DOM.
ISSN:0048-9697
1879-1026
DOI:10.1016/j.scitotenv.2020.140378