The Reactivity of Green Rust Towards Redox-Stable Trace Metals in Reducing Environments

点击翻译按钮获取中文摘要

This award from the Environmental Chemical Sciences Program in the Division of Chemistry supports Professor Evert Elzinga and his students to study green rust (GR). GR is an iron-hydroxide mineral that forms in certain natural and engineered environments such soils along river banks, aquifers, drinking water lines, and barriers used for groundwater remediation. These minerals are very reactive and are known to degrade both organic and inorganic pollutants through reduction/oxidation (redox) reactions. Little is known about the reactions involved. The goal of this project is to study the chemical reactivity of GR with a series of environmentally relevant trace metals. The work aims to improve knowledge of the mobility of metal pollutants in reducing environments and provide basic insights into the surface chemistry of green rust minerals. The project provides scientific training for graduate students. Underrepresented minority undergraduate students from the Louis Stokes Alliances for Minority Participation (LSAMP) program at Rutgers-Newark are involved in the research.Trace metals of different sizes and valences (Mn(II), Ni(II), Zn(II), Cd(II), Pb(II) and Cr(III)) are reacted with GR in pre-equilibrated anoxic suspensions over a range of environmentally relevant geochemical conditions. Metal sorption is being monitored over time, and operative mechanisms are determined using synchrotron-based X-ray absorption spectroscopy. The team studies Fe atom cycling between the aqueous phase and the GR solid with Fe-55 radiotracers, and monitors the structure and morphology of GR using X-ray diffraction and transmission electron microscopy analyses. The research provides educational opportunities and exposure to research to graduate and undergraduate students, including members of underrepresented groups.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.