The Innovation Team of Soil Health Care of the Institute of Agricultural Resources and Regional Planning (IARRP) of the Chinese Academy of Agricultural Sciences (CAAS), has made significant progress in understanding the interface mechanism of the impact of straw-derived dissolved organic carbon on the sorption of arsenic by iron oxides. Their related findings, titled "Arsenic(III) sorption on organo-ferrihydrite coprecipitates: Insights from maize and rape straw-derived DOM," have been published in "Chemosphere" (IF = 8.9).

The enrichment and exceeding of arsenic in farmland soil are important environmental issues affecting the quality and health of soil in China. Soil iron oxides, especially ferrihydrite, are typical minerals that affect the mobility and bioavailability of arsenic in soil. With a high rate of straw return in China, the release of dissolved organic matter from straw profoundly affects the surface properties of ferrihydrite and its interfacial sorption mechanism with arsenic. However, the interaction of straw-derived dissolved organic matter with ferrihydrite and its molecular mechanism in arsenic interface adsorption are still unclear and require further research.

This study utilized dissolved organic matter (DOM) extracted from typical maize and rapeseed straw in China to form organic-ferrihydrite composites (OFC) through coprecipitation with ferrihydrite (Fh). With techniques including synchrotron X-ray absorption spectroscopy, the study found that the loading of straw-derived dissolved organic matter significantly reduced the adsorption of arsenic by organic-ferrihydrite composites. However, the influence of solution ionic strength on this process was limited, indicating that organic-ferrihydrite composites primarily immobilize arsenic through inner-sphere complexation. Under high pH conditions, straw-derived dissolved organic matter increased the mobility of arsenic associated with organic-ferrihydrite composites. These research findings provide important reference for the conservation of farmland with arsenic enrichment, the safe utilization of farmland with arsenic exceeding standards, and the management of straw return in China.

Prof. Yang Jianjun, from the IARRP, is the corresponding author of the paper. This work was found by the Top-Notch Young Talents Program of China, National Natural Science Foundation of China, the earmarked fund for China Agriculture Research System, and the Agricultural Science and Technology Innovation Program of Chinese Academy of Agricultural Science.

Citation and original link:

Darma, A.; Liu, Y.; Xia, X.; Wang, Y.; Jin, L.; Yang, J., Arsenic(III) sorption on organo-ferrihydrite coprecipitates: Insights from maize and rape straw-derived DOM. Chemosphere 2024, 352, 141372.

Paper link: https://doi.org/10.1016/j.chemosphere.2024.141372