Grantee Research Project Results

Kinetic and Mechanistic Framework for Remediation Using Zerovalent Iron (SEERII)

EPA Grant Number: R829422E03
Title: Kinetic and Mechanistic Framework for Remediation Using Zerovalent Iron (SEERII)
Investigators: Zhang, Tian C. , Shea, Patrick J.
Institution: University of Nebraska at Lincoln
EPA Project Officer: Chung, Serena
Project Period: August 5, 2002 through August 4, 2004 (Extended to August 4, 2005)
Project Amount: $215,061
RFA: EPSCoR (Experimental Program to Stimulate Competitive Research) (2001) RFA Text | Recipients Lists
Research Category: EPSCoR (The Experimental Program to Stimulate Competitive Research)

Description:

Objective:

This project further investigates zerovalent iron (Fe⁰) as an alternative remediation technology for treating soil and water contaminated with nitrate and chlorinated or nitrogenated organic compounds. Project objectives of our project are to: (1) elucidate the kinetics and mechanisms of Fe⁰ treatment processes, (2) develop new approaches to enhance Fe⁰ performance, and (3) implement a successful cleanup of a contaminated field site. Major hypotheses are that (1) the semiconducting properties of (hydr)oxides coating the Fe⁰ surface and electric field enhancement arising from surficial cations are major operating mechanisms for effective contaminant reduction during oxidation of Fe⁰, and (2) the performance of Fe⁰ treatment systems can be enhanced by certain amendments (such as aluminum and iron salts) and optimizing reaction conditions (particularly Eh and pH). Therefore, with careful management, Fe⁰ treatment processes can be sufficiently robust for effective yet practical on-site remediation.

Approach:

The project will be conducted using batch and column reactors and field-scale equipment. To approach Objective 1, the reduction of nitrate, chlorinated and nitrogenated organic contaminants by Fe⁰ will be studied. Major hypotheses centering on process kinetics and mechanisms (semiconductor and electric field enhancement) and the role of iron oxides (particularly magnetite and green rusts) in promoting chemical reduction will be tested. A "Langmuir" model describing the process will be developed and tested. To approach Objective 2, technologies to regenerate reactive sites, remove passivating films, overcome clogging of permeable Fe⁰ barriers through addition of aluminum and iron salts, and optimize reaction conditions (primarily pH and Eh) will be developed. Finally, a field demonstration project will be conducted (Objective 3) to test the technologies developed in the laboratory.

Expected Results:

The proposed kinetic model will be calibrated using experimental results. Several new procedures for enhancing Fe⁰ treatment processes will result from the project. Further evaluation of the roles of iron oxides and environmental variables will lead to broader use of this promising treatment technology. A successful field demonstration is anticipated.

Publications and Presentations:

Publications have been submitted on this project: View all 34 publications for this project

Journal Articles:

Journal Articles have been submitted on this project: View all 14 journal articles for this project

Supplemental Keywords:

cleanup, sediments, restoration, engineering, environmental chemistry., Scientific Discipline, Geographic Area, Waste, Water, POLLUTANTS/TOXICS, Remediation, State, Contaminated Sediments, Groundwater remediation, Ecology and Ecosystems, Water Pollutants, kinetic studies, sediment treatment, water quality, contaminated sediment, Nebraska (NE), groundwater contamination, contaminated aquifers, environmental engineering, chlorinated organic compounds, nitrate, contaminated groundwater, contaminated soil, remediation technologies, reductive treatment, fate and transport, hazardous waste, zero valent iron, ecology assessment models, predictive understanding, dehalogenation

Progress and Final Reports:

The perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Conclusions drawn by the principal investigators have not been reviewed by the Agency.