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Interactions between uronic acids and chromium(III)
Zeynep Cetin1, Cetin Kantar, Musa Alpaslan
1Department of Environmental Engineering, Mersin University, Engineering Faculty, Ciftlikkoy Kampusu, 33343 Mersin, Turkey.
Environmental Toxicology and Chemistry
|March 19, 2009
Summary
Chromium(III) readily binds to uronic acids found in bacterial exopolymeric substances, forming complexes that influence its environmental behavior. This study quantifies chromium binding with specific uronic acids like glucuronic and galacturonic acid.
Area of Science:
- Environmental Chemistry
- Biogeochemistry
- Microbial Ecology
Background:
- Bacterial exopolymeric substances (EPS) are crucial in aquatic environments.
- Chromium (Cr(III)) is a metal ion with significant environmental implications.
- Uronic acids are key components of bacterial EPS, influencing metal interactions.
Purpose of the Study:
- To investigate the complexation of Chromium(III) with uronic acids.
- To determine the stoichiometry and stability of Cr-uronic acid complexes.
- To understand the influence of these complexes on Cr(III) environmental fate.
Main Methods:
- Laboratory ion-exchange experiments.
- Chemical equilibrium modeling using FITEQL software.
- Analysis of Cr(III) binding with galacturonic, glucuronic, and alginic acids.
Main Results:
- Cr(III) forms 1:1 and 1:2 complexes with glucuronic and galacturonic acids.
- Cr(III) binding with alginic acid can be modeled as a 1:1 complex.
- Complexation primarily occurs via carboxylic groups across a range of pH conditions (pH < 8).
Conclusions:
- Cr(III)-uronic acid complex formation significantly affects Cr(III) transport and solubility.
- These complexes can alter the bioavailability of chromium in natural systems.
- Understanding these interactions is vital for predicting chromium's environmental impact.
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