Estimation of transport parameters of RO membranes for seawater desalination

Membrane transport parameters from a running plant data were studied to understand their changes with time, as well as the causes of membrane fouling under various running conditions. First, the mass‐transfer coefficient of a spiral‐type reverse osmosis (RO) element was measured using a polyamide membrane, designated UTC‐80, and an appropriate correlation equation was obtained. Then, a computer program was developed to obtain membrane transport parameters from flux and rejection data of an actual RO plant. When it became apparent that the temperature corrections should be applied, laboratory experiments were used to determine them. Thus, the time course change of both solution and salt permeabilities and the relation between them could be followed. The permeability of each ion or solute can be obtained by the same method when their analytical data are available.