Scope and Motivation. Mass Conservation and Macroscopic Mass Balances. The Principle of Conservation of Mass and the Total Mass Balance. Macroscopic Mass Balance for a Chemical Species in a Mixture. Diffusive Transport: Introductory Concepts. Diffusion Fundamentals. Diffusion as a Mass Transfer Mechanism. Binary Systems. Pseudo-Binary Systems. Multicomponent Systems. One-Dimensional, Steady Diffusion. Diffusion through a Solid Membrane. Analysis of a Pervaporation Process. Evaporation of a Liquid into a Stagnant Gas Layer: The Stefan Problem. Diffusive Transport: Applications of the Diffusion Equation. Conservation of Mass of a Chemical Species in a Mixture. One-Dimensional, Steady Diffusion. Steady Diffusion through an Annular Membrane. Diffusion from a Sphere Submerged in a Stagnant Fluid: Dissolution of a Spherical Solid Particle. Transient Diffusion. Transient Mass Transfer in a Flat Membrane. Transient Mass Transfer in Long Cylinders and Spheres. Transient Leaching from a Semi-Infinite Solid. Diffusive Transport in Reactive Systems. Treatment of Reactive Systems. Transport and Homogeneous Reaction in a Biofilm. Diffusion with Heterogeneous Chemical Reaction. Enhanced (Facilitated) Diffusion. Convective Transport. The Role of Momentum Balances in Convective Transport. Mass and Momentum Balances. Velocity Distributions in One-Dimensional Flows. Velocity Distribution between Parallel Plates When the Fluid Movement Is Induced by the Motion of One of the Plates (Simple Shear Flow) Velocity Distribution in a Liquid Film Flowing Down on an Inclined Surface. Velocity Distribution for Developed Flow in a Pipe. Convective Mass Transfer in the Entrance Region of a Pipe in Laminar Flow. Convective Mass Transfer Correlations. Hydrodynamic Dispersion. The Concept of Hydrodynamic Dispersion and Taylor-Aris Theory. Generalization of the Dispersion Model. Turbulent Dispersion. Solutions of the Convective-Dispersion Equation. Transport in Multiphase Systems. Multiphase Systems and Porous Media. Single-Phase Flow in Porous Media: Darcy's Law. Diffusion in Porous Media and Multiphase Systems. Dispersion in Porous Media. Experimental Determination of the Longitudinal Dispersivity in 1-D Flows. Experimental Determination of the Lateral Dispersivity in 1-D Flows. Transport in Porous Media: Fluid/Solid Interactions. Equilibrium Adsorption in Porous Media: Linear Equilibrium. Equilibrium Adsorption in Porous Media: Nonlinear Equilibrium. Transport in Porous Media with Rate-Limited Adsorption and/or Chemical Reaction. Adsorption and Reaction in Porous Media with Mass Transfer Limitations. References. Appendix A: Vectors and Vector Operations. Appendix B: The Continuity Equation. Appendix C: Mass Transfer Point Equations. Appendix D: Bessel Functions.