Ferrous iron-induced ternary complexation of arsenite with dissolved organic matter: insights from X-ray absorption spectroscopy

Description

Studies have highlighted that natural organic matter (NOM) can bind arsenic (As) species by ternary complexation via a polyvalent metal cation (Mn+) bridging (As-M-NOM) and, therefore, regulate As mobility at the soil/sediment-water interface. Ferric iron (Fe3+) has been identified as a key bridging metal ion for such complexation. However, high As in natural waters often coexist with high concentrations of ferrous iron (Fe2+) instead of Fe3+, together with dissolved organic matter (DOM). Therefore, it is important to assess whether Fe2+ can induce a similar complexation of As species with DOM to understand the complete role of As-DOM interactions in As mobility. Despite its importance, the possible role of Fe2+ in the As-DOM interactions has not been thoroughly investigated. Therefore, we incubated arsenite with the original and hydrogenated Leonardite Humic Acid (LHA) and Suwannee River aquatic DOM (SRNOM) in the presence of varying concentrations of Fe2+ to determine its extent of bindings onto DOM under anoxic conditions. The role played by Fe2+ in the As binding was determined by the As and Fe K-edge X-ray absorption spectroscopic (XAS) analysis of the As-Fe-DOM complexes. These data files are related to the manuscript published on this study.

Institutions

• Indian Institute of Science Education and Research Bhopal

  Madhya Pradesh, Bhopal

Categories

Funders

• Science and Engineering Research Board

  Delhi, India

  Grant ID: ECR/2017/002353
• Scheme for Transformational and Advanced Research in Sciences (STARS), Ministry of Education (MoE), Government of India

  Grant ID: MoE-STARS/STARS-2/2023-0408

Licence