Abstract:

Osmosis technologies are proposed for educational purposes, especially for practical trainings of graduated and under-graduated students from different educational fields (Physics, Chemical Engineering, Environmental and Materials Engineering, etc.). Engineered Osmosis (EO) is an emerging platform technology that includes both isothermal and non-isothermal membrane processes used for production of water and energy. EO includes three isothermal processes Forward Osmosis (FO), Pressure Retarded Osmosis (PRO) and Reverse Osmosis (RO); and three non-isothermal processes Thermo-osmosis (TO); Osmotic Distillation (OD) and Osmotic Membrane Distillation (OMD).

EO offers a unique learning opportunity for students permitting them explore different membrane separation processes running with different driving forces (temperature, concentration, hydrostatic pressure, partial vapor pressure, or in general chemical potential difference between both sides of the membrane). The key engineering differences between these osmosis membrane processes, benefits, similarities and drawbacks are emphasized.

Osmosis technologies are used to teach heat and mass transfer fundamentals. Students understand and differentiate between the osmosis membrane processes, learn the mechanism of transport through each type of membrane, bring into practice the non-equilibrium thermodynamics theory, understand the effects of temperature polarization (i.e. feed and permeate temperature boundary layers) and concentration polarization (i.e. feed and permeate concentration boundary layers), select hydrodynamic conditions depending on the characteristic of each membrane, select and use adequately the draw solute concentration and its effect on the osmotic pressure, calculate the permeate fluxes and compare them with the experimental ones, etc.

Acknowledgment: The author gratefully acknowledges the financial support of Abengoa Water S.L.U. (Artículo 83: 320/2011, MEMsa and 85/2013, HOFI-MED-Plant).

Keywords:

Forward Osmosis, Pressure Retarded Osmosis, Reverse Osmosis, Thermo-osmosis, Osmotic Distillation, Osmotic Membrane Distillation.