Imperial College London
Alternate

ProfessorDominikWeiss

Faculty of Engineering, Department of Earth Science & Engineering

Professor of Environmental Geochemistry
 
 
 
//

Contact

 

+44 (0)20 7594 6383d.weiss

 
 
//

Location

 

2.39Royal School of MinesSouth Kensington Campus

//

Summary

 

Publications

Citation

BibTex format

@article{Kirby:2019:10.1021/acs.jchemed.8b01036,
author = {Kirby, ME and Bullen, JC and Hanif, MD and Heiba, HF and Liu, F and Northover, GHR and Resongles, E and Weiss, DJ},
doi = {10.1021/acs.jchemed.8b01036},
journal = {Journal of Chemical Education},
pages = {215--220},
title = {Determining the effect of pH on iron oxidation kinetics in aquatic environments: exploring a fundamental chemical reaction to grasp the significant ecosystem implications of iron bioavailability},
url = {http://dx.doi.org/10.1021/acs.jchemed.8b01036},
volume = {97},
year = {2019}
}
Download

RIS format (EndNote, RefMan)

TY  - JOUR
AB  - Understanding the controls of the oxidation rate of iron (Fe) in oxygenated aquatic systems is fundamental for students of the Earth and Environmental Sciences as it defines the bioavailability of Fe, a trace metal essential for life. The laboratory experiment presented here was successfully developed and used during a third-year undergraduate lab course at Imperial College London for several years. It employs ultraviolet–visible (UV–vis) spectroscopy calibrated externally with 0 to 50 μM Fe2+ standards created in a 492 μM ferrozine and 0.43 M acetate matrix. The students conducted the oxidation experiments in stirred batch reactors at equilibrium with atmospheric oxygen. The solution contained 40.5 μM initial Fe2+ concentration and a 5.1 mM imidazole buffer. The pH was adjusted to values between 7.22 and 7.77. The students observed a pseudo-first-order reaction with respect to Fe2+ concentration. Plotting the logarithms of the apparent rate constants (k′) at different pH values leads to a gradient of 2.2 ± 0.2 min–1 pH–1, indicating a second-order reaction with respect to OH– concentration, in agreement with published literature. The oxidation reaction occurred rapidly (tens of seconds to tens of minutes) indicating that in oxygenated aquatic systems, Fe3+ will be the dominant oxidation state, significantly reducing the bioavailability of Fe. The simple laboratory experiment presented here allows the students to learn about kinetic parameters for a fundamental chemical reaction. It allows the students to explore the significant implications this has for aquatic ecosystems.
AU  - Kirby,ME
AU  - Bullen,JC
AU  - Hanif,MD
AU  - Heiba,HF
AU  - Liu,F
AU  - Northover,GHR
AU  - Resongles,E
AU  - Weiss,DJ
DO  - 10.1021/acs.jchemed.8b01036
EP  - 220
PY  - 2019///
SN  - 0021-9584
SP  - 215
TI  - Determining the effect of pH on iron oxidation kinetics in aquatic environments: exploring a fundamental chemical reaction to grasp the significant ecosystem implications of iron bioavailability
T2  - Journal of Chemical Education
UR  - http://dx.doi.org/10.1021/acs.jchemed.8b01036
UR  - https://pubs.acs.org/doi/10.1021/acs.jchemed.8b01036
UR  - http://hdl.handle.net/10044/1/74601
VL  - 97
ER  -
Download