State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing 210008, China; University of Chinese Academy of Sciences, Beijing 100049, China.
State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing 210008, China.
Sci Total Environ. 2020 Jun 15;721:137827. doi: 10.1016/j.scitotenv.2020.137827. Epub 2020 Mar 9.
The binding of dissolved organic matter (DOM) with metals affects the latter's biogeochemical processing in the environment. This study used multi-spectroscopic analyses to compare the heterogeneities of the Cu(II) binding properties of DOM derived from fresh and pyrolyzed biomaterials. The results showed that the DOM derived from fresh macrophyte (MDOM) and their corresponding biochar (BDOM) consisted mostly of protein-like and humic-like substances, respectively. The stability constant (log K) of protein-like matter in the MDOM was 5.27, and the values of humic-like components in the BDOM were 4.32-5.15. Compared with the MDOM, the BDOM exhibited lower affinities and active binding sites for Cu(II). In addition, the BDOM contents decreased after pyrolysis. Therefore, the pyrolysis of fresh biomaterials into biochar is a promising method for reducing the potential migration risk posed by Cu(II) due to the MDOM being a positive carrier for Cu(II) contamination. Polysaccharide was the only functional group that participated in the binding of Cu(II) in both MDOM and BDOM. Aliphatic groups and amides associated with protein-like matter were responsible for the Cu(II) binding to MDOM, whereas phenolic and aromatic groups mainly participated in the complexation of BDOM-Cu(II). The CO group of amide I in the MDOM, and polysaccharide in the BDOM, showed the fastest response to Cu(II). This study was helpful for elucidating the effects of fresh and pyrolyzed biomaterials (biochars) on the environmental behavior of Cu(II) at the molecular level.
溶解有机质（DOM）与金属的结合会影响后者在环境中的生物地球化学过程。本研究采用多种光谱分析方法比较了新鲜和热解生物材料衍生 DOM 对 Cu(II)结合特性的不均匀性。结果表明，来自新鲜大型植物的 DOM（MDOM）及其相应的生物炭（BDOM）主要由类蛋白和类腐殖质物质组成。MDOM 中类蛋白物质的稳定常数（log K）为 5.27，BDOM 中类腐殖质组分的值为 4.32-5.15。与 MDOM 相比，BDOM 对 Cu(II)的亲和力和活性结合位点较低。此外，BDOM 含量在热解后减少。因此，将新鲜生物材料热解成生物炭是一种有前途的方法，可以降低由于 MDOM 是 Cu(II)污染的正载体而导致的 Cu(II)潜在迁移风险。多糖是 MDOM 和 BDOM 中唯一参与 Cu(II)结合的官能团。与类蛋白物质相关的脂肪族基团和酰胺基负责 MDOM 与 Cu(II)的结合，而酚类和芳族基团主要参与 BDOM-Cu(II)的络合。MDOM 中酰胺 I 的 CO 基团和 BDOM 中的多糖对 Cu(II)表现出最快的响应。本研究有助于阐明新鲜和热解生物材料（生物炭）对 Cu(II)在分子水平上的环境行为的影响。
