Ferrihydrite surface behavior
Collaborative Research: Toward a unified model for ferrihydrite nanoparticles behavior in the environment: a multi-pronged investigation of surface structure and reactivity
NSF Award 1404643: Chemistry Division, Environmental Chemical Sciences Program
Project Collaborators: Nadine Kabengi, Georgia State University; James Kubicki, University of Texas at El Paso; Michael Machesky, Illinois State Water Survey
Ph.D. students: Nefeli Bompoti (graduated), Yaguang Du (graduated)
Undergraduate students: Austin Connell, Jennifer Mulqueen, Rachel Albino, Will Adsit, Harrison Mangines
This project is a collaboration between four different teams: an environmental engineer and geochemist (Dr. Chrysochoou), a soil scientist (Dr. Kabengi), a computational chemist (Dr. Kubicki) and a modeler (Dr. Machesky). This group effort is investigating the interplay between the bulk structure, surface properties, and environmental reactivity of ferrihydrite, a ubiquitous complex iron oxide. To meet this challenge, the groups are integrating experimental thermodynamics obtained through flow adsorption microcalorimetry with computational chemistry, spectroscopy, and surface complexation modeling. This framework utilizes, for the first time, a recently proposed ferrihydrite structure to model its surface reactivity. The ultimate goal of the surface studies is to develop a predictive-mechanistic understanding of the interplay between a surface structure and its environmental reactivity, which will demonstrate the strength and applicability of incorporating directly measured thermodynamics data into environmental studies of mineral-solution interfaces. The project’s impact is enhanced by the inclusion of its intellectual approaches in many courses taught by faculty in the Chemistry, Geoscience, and Environmental Engineering departments at the institutions, which exposes a larger number of students to important environmental geochemical concepts and techniques.
Bompoti N., Chrysochoou M. and Machesky M. 2019. A unified surface complexation modeling approach for chromate adsorption on iron oxides, Environmental Science and Technology, 53(11), 6352-6361.
Bompoti N., Chrysochoou M. and Machesky M. 2018., Assessment of modeling uncertainties using a multi-start optimization tool for surface complexation equilibrium parameters (MUSE), ACS Earth and Space Chemistry, doi:10.1021/acsearthspacechem.8b00125
Kubicki J., Kabengi N., Chrysochoou M. and Bompoti N. 2018. Density functional theory modeling of chromate adsorption onto ferrihydrite nanoparticles, Geochemical Transactions, 19:8, https://doi.org/10.1186/s12932-018-0053-8.
Bompoti N., Chrysochoou M. and Machesky M., 2017. Surface structure of ferrihydrite: Insights from modeling surface charge. Chemical Geology, DOI: 10.1016/j.chemgeo.2016.12.018.
Kabengi N., Chrysochoou M., Bompoti N. and Kubicki J. 2017. An integrated flow microcalorimetry, infrared spectroscopy and density functional theory approach to the study of chromate complexation on hematite and ferrihydrite, Chemical Geology, http://dx.doi.org/10.1016/j.chemgeo.2017.01.017.
Bompoti N., Chrysochoou, M., Machesky, M.. “Advances in surface complexation modeling for chromium adsorption on iron oxides,” Juried Conference paper Geochicago 2016: Sustainability, Energy, and the Geoenvironment. Chicago, August 14-18, v.273, 2016, p. 1. doi:10.1061/9780784480168.001
Johnston C.P. and Chrysochoou M.. “Mechanisms of Chromate, Selenate, and Sulfate Adsorption on Al-Substituted Ferrihydrite: Implications for Ferrihydrite Surface Structure and Reactivity,” Environmental Science and Technology, v.50, 2016, p. 3589. doi:10.1021/acs.est.5b05529
Bompoti N., Chrysochoou M. and Machesky M., 2018. Towards a unified thermodynamic database: U (VI) and Cr (VI) adsorption on iron oxides. Goldschmidt 2018, Boston, MA, August 12 -17. (oral presentation)
Bompoti N., Chrysochoou M. and Machesky M., 2018. Iron oxide – solution interface: Insights from Surface Complexation Modeling. 255thAmerican Chemical Society National Meeting & Exposition, New Orleans, March 18-22. (oral presentation)
Chrysochoou M., Bompoti N., and Machesky M., 2018.The MUSE: A MUlti – Start optimization algorithm for surface complexation Equilibrium parameters in complex systems. Symposium in Honor of James A Davis, 255th American Chemical Society National Meeting & Exposition, New Orleans, March 18-22. (oral presentation)
Bompoti N., Chrysochoou M. and Machesky M., 2017. Advances on reactive transport modeling: Modeling adsorption of heavy metals on iron oxides using an innovative surface complexation model. SETAC North America 38th Annual Meeting, Minneapolis, MN, Nov 12-16, 2017.
Bompoti N., Chrysochoou M. and Machesky M., 2017. Predicting Chromate Adsorption on Iron Oxides: A surface complexation modeling study. 2017 ASA, CSSA, and SSSA Annual Meeting in Tampa, FL, Oct. 22-25.
Bompoti N., Chrysochoou M. and Machesky M., 2017. The MUSE: A MUlti –start optimization algorithm for Surface complexation Equilibrium parameters. Goldschmidt 2017, Paris, France, August 13 -18, 2017.
Bompoti N., Chrysochoou M. and Machesky M., 2017. The MUSE application: A Unified Surface Complexation Modeling approach for chromate binding to iron oxides. Goldschmidt 2017, Paris, France, August 13 -18, 2017.
Bompoti N., Chrysochoou M. and Machesky M. 2016. Surface complexation modeling for chromium adsorption on iron oxides, A&WMA Conference: Climate Change: Risks, Rewards and Resiliency, October 27th, 2016
Chrysochoou M., Kabengi N. Bompoti N., Kubicki J. and Machesky M. 2016. Resolving the fine-scale reactivity of chromate complexation on iron oxide surfaces, 251st American Chemical Society National Meeting & Exposition, San Diego, CA, March 13-17.
Chrysochoou M. and Bompoti N. 2016. Carbonate adsorption on ferrihydrite: a semi-quantitative IR study, 251st American Chemical Society National Meeting & Exposition, San Diego, CA, March 13-17.
Bompoti N., Chrysochoou M. and Machesky M. 2016. Surface complexation modelling of chromate adsorption on iron oxides, 251st American Chemical Society National Meeting & Exposition, San Diego, CA, March 13-17.
Johnston C.P. and Chrysochoou M. 2016. Oxyanion Adsorption on Al-Substituted Ferrihydrite, 251st American Chemical Society National Meeting & Exposition, San Diego, CA, March 13-17.
Bompoti N., Chrysochoou M. and Machesky M. 2015. Massachusetts Water Resources Research Center, New England Graduate Student Water Symposium, University of Massachusetts, September 2015, oral presentation.
K-12 Outreach activities:
Teaching soil properties to K-4: Southeast Elementary School, Mansfield, CT
Dr. Chrysochoou and NSF-funded Ph.D. student Nefeli Bompoti participated in a 4-week program of Southeast Elementary School, during which K-4 students spent 4 afternoons exploring different areas of science. In the modules taught by Dr. Chrysochoou and Ms. Bompoti, students learned to recognize different soil types (sand, silt and clay) and also how soil acts as a filter for pollution. They also learned how vegetation affects soil erosion and the resulting water quality by creating their own water filter from soil and grass in the school back yard. Hands got dirty!
4th graders conducting water flow experiments with Ph.D. student Nefeli Bompoti
Teaching soil-contaminant interactions to high school students: UCONN Explore Engineering Program
In this program, high school seniors spend 5 days at UCONN, learning about different aspects of engineering by attending lectures and participating in hands on activities. In this lab activity, students learned about soil-contaminant interactions by measuring hexavalent chromium concentrations in an initial solution, in the filtrate collected from a soil column, and in the soil itself before and after interaction with the solution. The students learned to use the spectrophotometer, construct a calibration curve, observed the use of an X-ray Fluorescence spectrometer and learned how to do a mass balance. The handout for this activity may be downloaded here Highschool activity handout