Environmental Chemistry

The course deals with the fundamentals and critical analysis of chemical processes one encounters in the field of Environmental Engineering. The course deals with:• Application of equilibrium equations and material balance equations to calculate conditions in environmental systems at equilibrium using the concept of components.• Use of chemical equilibrium programs such as VMINTEQ to calculate conditions in environmental systems at equilibrium• Application of kinetic equations, stoichiometric relationships and material balances to calculate conditions in environmental systems in which reactions occur that are not at equilibrium.• Application of fundamental aspects of thermodynamics to describe equilibrium conditions in environmental systems.• Defining equilibrium and kinetic limitations as relating to environmental systems and the relative importance of each for chemical processes in environmental systems.• Knowledge of important terminology for chemical processes occurring in environmental systemsINTENDED AUDIENCE :Environmental engineering professionals and students pursuing a degree with emphasis in Environmental engineeringPREREQUISITES :Entry level chemistry courseINDUSTRIES SUPPORT :CPCB, SPCB, Degremont, ERM, Ramky Enviro Engineers, Veolia Water, SFC Environmental Technologies Pvt. Ltd., Nalco Water, VA Tech Wabag, Ther

Week 1
I. IntroductionII. Fundamentals of chemical processes A. Introduction 1. Terminology 2. Fundamental Aspects of Chemical Processes a) Equilibrium b) Kinetics 3. Relationships between Equilibrium, Kinetics, steady-state B. Equilibrium 1. Introduction (importance, definitions) 2. Gibbs free energy a) Definition b) Process feasibility (criteria, driving forces) c) Application to reactions (1) Mixtures (2) Reactions d) Calculate Gibbs Energies (1) Standard conditions (2) Non-standard conditions (a) Concentration/activity (concept of activity; effect of activities, reaction quotient, equilibrium coefficient, relationship of activities and concentrations, determining activity coefficients, corrected equilibrium coefficients) (b) Temperature (van't Hoff equation) (c) Pressure (effect of change in volume) 3. Phase Equilibrium a) Introduction b) Gas-Liquid c) Fluid-Solid d) Multiphase 4. Equilibrium Models a) Introduction b) Chemical Equilibrium models (1) Structure (2) Example

Week 2 (3) Generalized Approach (a) Species (b) Components (c) Formation equation (d) Tableau (e) Component balance equations (f) Equilibrium equations (g) Solutions C. Kinetics 1. Reactions a) Introduction (importance, terminology) b) Factors affecting rates of reactions (1) Concentrations of reactants (2) Temperature c) Stoichiometry 2. Reactors a) General approach (rate equation, material balance) b) Material balances (1) Batch reactor (assumptions, material balances, stoichiometry examples) (2) Plug flow reactor (assumptions, material balances, stoichiometry examples) (3) Completely mixed reactor (assumptions, material balances, stoichiometry examples) c) Examples

Week 3: d) Reaction Kinetics for Reversible Reactions
3. Determination of rate equation a) Requirements (1) Form of equation (rates, graph, regression for n) (2) Values of coefficients b) Approaches (1) Rate-based (rates, regression, linear or nonlinear, one-point) (2) Concentration-based (concentration model, regression, one-point) c) Regression (1) Linear (2) Linearized (3) Non-linearIII. Acid/Base Reactions A. Introduction (importance, terminology) B. Kinetics C. Equilibrium 1. Single Reaction a) Henderson-Haselbach Equation (1) Acid dissociation constant (2) pKa (3) Strength of Acid (4) Example

Week 4 b) Ionization Fractions
2. Models (multiple reactions) a) Recipe problems (1) Single acid in water (2) Single base in water (3) Mixture of acid and base (4) Titrations (5) Buffering b) Inverse Problems c) Computer solutions (VMINTEQ)

Week 5
1. Log C-pH Graphs a) Introduction b) Preparation c) Example 2. Carbonate System a) Introduction b) Closed system c) Open system 3. Equivalence Point 4. Buffer a) Introduction b) Application by VMINTEQ

Week 6
c) Buffer Intensity at various pH ranges d) Design of Buffers 5. Alkalinity, acidity (1) Definitions (a) Theoretical (b) Operational (2) Acidity (a) Mineral Acidity (b) Phenolphthalein Acidity (c) Total Acidity (3) Multiple Equivalence Points

Week 7
(4) Relationship among ALK,ACD, Ct,co3 (5) Mixing Problems (6) Conservative quantities (a) Introduction (b) Alkalinity due to Carbonate and Non- Carbonate Species (7) Example: Complex Acid/Base Problems
Week 8
IV. Aqueous Complex Formation A. Introduction 1. metals as acids 2. examples 3. terminology 4. importance B. Kinetics C. Equilibrium 1. Equilibrium Coefficients a) stepwise b) one-step 2. Strength of complexes 3. ModelsV. Precipitation A. Introduction 1. Terminology 2. Applications B. Kinetics 1. Relative Importance

Week 9
2. Steps a) Nucleation b) Crystal Growth c) Agglomeration d) Ripening (1) Definition (2) Types (a) Ostwald (b) More crystalline, less soluble 3. Controlling precipitation a) Promoting precipitation b) Inhibiting precipitation C. Equilibrium 1. Coefficients 2. Important concepts 3. Models a) General approach b) Problem types (1) Recipe (2) Solubility (3) Inverse recipe

Week 10
4. Competitive Precipitation 5. Predominance Area Diagram 6. Calcium carbonate precipitation a) Saturation indexesVI. Oxidation/Reduction A. Introduction 1. Terminology 2. Applications 3. Balancing Redox Reactions B. Kinetics 1. Importance 2. Models

Week 11
C. Equilibrium 1. Introduction 2. Alternatives for reaction feasibility a) Q/K approach b) pe approach (1) Definitions of pe, pe0 (2) Reaction feasibility (3) Models

Week 12
c) Eh approach (1) Galvanic cell (2) Nernst equation (3) Relationship of Eh, pe 3. Oxidation-Reduction Potential (ORP) Measurement
a) Introduction b) Advantages c) Limitation 4. Predominance Area Diagrams a) Introduction b) Examples 5. Corrosion a) Introduction b) Corrosion Cell c) Types d) control methods