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Aquatic Chemistry 367 Civil and Environmental Engineering. Meeting time: MWF 11:00-11:50am Meeting room: Abbott Auditorium in Pancoe Pavillion Instructor: Jean-Francois Gaillard, jf-gaillard@northwestern.edu Grader: Amy Dahl, a-dahl@northwestern.edu. Logistics. Introductions
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Aquatic Chemistry 367Civil and Environmental Engineering Meeting time: MWF 11:00-11:50am Meeting room: Abbott Auditorium in Pancoe Pavillion Instructor: Jean-Francois Gaillard, jf-gaillard@northwestern.edu Grader: Amy Dahl, a-dahl@northwestern.edu
Logistics • Introductions • http://www.civil.northwestern.edu/ehe/courses/ce-367/ce-367.htm • Keep on top of the homework!
Why study Aquatic Chemistry? • Required for life • Pollution transport almost always requires water • Many environmentally relevant reactions occur in water • Critical for controlling cycling of many elements • Nutrients • Toxins • Oxygen, nitrogen, carbon dioxide – atmosphere control
Applications of aquatic chemistry: • Arsenic • Chromium • Mercury • Acid mine drainage • Global warming
What is water? • Universal Solvent • Required for life • Molecular structure • Hydrogen bonding: water clustering • Anomalous behavior compared to other liquids
Hydrated Ion Me (H O) n+ 2 n What is in water? Soluble Species Soluble Species Suspended Particles Suspended Particles Small Complexes Small Complexes Particles Particles • • Colloidal, aggregates Colloidal, aggregates e.g., e.g., Inorganic Inorganic • • Oxides (Al, Fe, Mn, Si) Oxides (Al, Fe, Mn, Si) Metal Complex Metal Complex • • Adsorption: surface Adsorption: surface Me(CO Me(CO ) ) y y - - complexation complexation 3 3 n n • • Co Co - - entrainment entrainment Hydrated Hydrated Ion Ion Me Me (H (H O) O) n+ n+ 2 2 n n Living Organisms Living Organisms • • Intra/extra Intra/extra - - cellular cellular Complexes with Complexes with • • Oligoelements Oligoelements Macromolecules Macromolecules • • Toxicity Toxicity e.g., Fulvic Acid e.g., Fulvic Acid • • Defense Mechanisms Defense Mechanisms Sediments Sediments! e.g., amorphous or crystalline solids (precipitates and mineral formation) e.g., amorphous or crystalline solids
What is in water? • Dissolved ions: • Major Cations (Ca, Na, Mg, K, Fe) • Trace elements (Zn, Cr, Cu, Cd) • Anions (F, Cl, nitrate, sulfate) • Complexes (non-charged) • Organic molecules (humic substances) • http://www.ar.wroc.pl/~weber/kwasy2.htm • Particulate • Organic matter • Clays • Oxides
Chemical Reactions • Acid-base chemistry • Coordination chemistry • Precipitation and dissolution • Redox reactions
Kinetic approach • Does not assume equilibrium has been reached • Use a rate constant, k, to describe the rate of formation of products or consumption of reactants
Thermodynamic explanation • Assumes equilibrium of a reaction is reached • Simplifies solving mathematical expressions of chemical systems • Use an equilibrium constant, K, to describe ratio of products to reactants