Showing papers on "Forward osmosis published in 1989"
TL;DR: In this paper, a new class of selective reverse osmosis membranes is described and the performance of such membranes is demonstrated with an observed negative rejection of the organic ions of molecular weight lower than a few hundred daltons from NaCl.
119 citations
TL;DR: Osmosis across a semipermeable membrane is usually treated in terms of thermodynamics, but the equations for osmosis can also be derived from kinetic considerations by accounting for binding between solvent and solute molecules.
Abstract: Osmosis across a semipermeable membrane is usually treated in terms of thermodynamics, but the equations for osmosis can also be derived from kinetic considerations. Since fewer solvent molecules bombard the semipermeable membrane from the solution side, a kinetic pressure difference (osmotic potential) is generated into pore openings. Intermolecular forces cancel each other and do not affect the osmotic potential. On the other hand, osmotic flow is dependent on intermolecular cohesive forces permitting the generation of large negative pressures in the membrane pores. Osmosis is therefore a unique property of liquids, whereas intermolecular cohesive forces do not affect diffusion. Osmotic pressure up to 180 atm can be correctly determined from the reduction in saturated vapor pressure above the solution because osmotic pressure and reduction in vapor pressure to some extent are analogous phenomena. Osmotic pressures up to 180 atm may also be correctly determined from kinetic considerations by accounting for binding between solvent and solute molecules (4-5 water molecules per solute molecule for sucrose solutions).
29 citations
TL;DR: In this article, a mathematical model was proposed and solved, which can predict the permeate flux, as well as the mass of deposits on the membrane as a function of time, based on the following assumptions: (1) the rate of deposition is proportional to the deviations from equilibrium conditions.
16 citations
Journal Article•
9 citations
TL;DR: In this paper, a high flux, thin film composite reverse osmosis (RO) membrane was used to concentrate L-phenylalanine (L-Phe) from clarified bioreactor harvest media.
7 citations
TL;DR: In this article, a mathematical model was tested to predict the performance of two different membrane configurations at Doha Reverse Osmosis Plant (DROP), based on a generalized transport equation system involving solvent water and any number of completely ionized solutes with different valencies.
5 citations
01 Jan 1989
TL;DR: In this paper, the reverse osmosis separation of aqueous NaC1, MgC12, Na2SO4 and MgSO4 solutions were carried out using CA membranes and 3 composite membranes.
Abstract: Reverse osmosis separation of aqueous NaC1, MgC12, Na2SO4 and MgSO4 solutions were carried out using CA membranes and 3 composite membranes. Membrane constants were calculated by the Spiegler-Kedem's transport model. Hydraulic permeability decreases with increase of concentration of solute in feed, only depends upon osmotic pressure on the surface of the membrane but not upon salt spiecies. Distribution coefficient of salt to CA measured separately was dependent upon concentration of salt in feed and salt spiecies. Diffusion coefficient of each salt in CA (90) membrane calculated decreases with osmotic pressure on the surface of the membrane up to 1 MPa but almost are constant beyond that pressure.
2 citations