Modeling mass transfer using surface morphology in full-scale reverse osmosis membrane processes

    Authors

    Y. M. Fang;S. J. Duranceau

    Comments

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    Abbreviated Journal Title

    Desalin. Water Treat.

    Keywords

    Membrane active-layer; Reverse osmosis; Mass transfer coefficients; Concentration polarization; Mathematical models; CONCENTRATION POLARIZATION; SYSTEMS; RO; Engineering, Chemical; Water Resources

    Abstract

    The influence of surface characteristics on membrane process performance is considered significant and is not well understood. Current mass transport models generally assume constant mass transfer coefficients (MTCs) based on a homogeneous flat surface. This study evaluated membrane mass transfer by incorporating surface morphology into a diffusion-based model assuming that the MTCs are dependent on the thickness variation of the membrane's active layer. Concentration polarization is also affected by this nonuniform surface property and was incorporated into the model. A simulation was performed using parameters from a full-scale 4.5million gallon per day brackish water reverse osmosis membrane process. The process was simulated by modeling one thousand uniform slices of the membrane channel and the permeate water quality was determined locally through a finite difference approach. It was determined that solute mass transport is controlled by diffusion in the nonhomogeneous thinner regions (membrane valleys) of the active layer. This nonuniform surface affected the concentration polarization layer, where more solutes tended to accumulate within the valleys than on the ridges. Prediction of the permeate total dissolved solids concentration was accurate, ranging between 5 and 15%, as measured as an average percent difference between predicted and actual values.

    Journal Title

    Desalination and Water Treatment

    Volume

    51

    Issue/Number

    34-36

    Publication Date

    1-1-2013

    Document Type

    Article

    Language

    English

    First Page

    6459

    Last Page

    6471

    WOS Identifier

    WOS:000326371800003

    ISSN

    1944-3994

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