The science of reverse osmosis-mechanisms, membranes, transport and applications

Abstract

-A view of the science of reverse osmosis on the basis of the preferential sorption-capillary flow mechanism is presented. Preferential sorption at the membrane-solution interface is a function of solute-solventmembrane material interactions arising from polar-, steric-, nonpolar-, and/or ionic-character of each one of the above components. Quantitative parameters for characterizing solutes and membrane materials at aqueous solution-membrane interfaces have been generated. Basic transport equations suitable for membrane specification and system analysis, and applicable for all membrane materials and membranes at all levels of solute separations have been developed for reverse osmosis systems involving aqueous solutions and preferential sorption of water at the membrane-solution interface. The polar, steric, and nonpolar parameters characterizing solutes have been built into the above transport equations through appropriate additional equations and correlations. As a result, it is now possible to predict the performance of a membrane for a large number of single and mixed solute aqueous feed solutions from only a single set of experimental reverse osmosis data for a reference NaC1-H20 feed solution. This is illustrated.

Reverse Osmosis Concentration of Flavor Components in Apple Juice-and Grape Juice-Waters

“…Tables II and III give the experimental data on concentrations of each flavor component identified in the apple juice-and grape Table I and applicaiion of relevant equations governing reverse osmosis transport and system analysis. These equations, which have been derived, discussed, verified and reviewed extensively in the literature (12b, [17][18][19][20][21], need only to be recalled for the purpose of this discussion. There are essentially four steps involved in the procedure for predicting solute concentrations in the concentrate and permeate solutions; these steps may be outlined as follows.…”

“…O. AO and <l at 5" C by system analysis. Under isothermal operating conditions, the following relationships are applicable to the reverse osmosis systems involved in this work (19)(20)(21): . exp~-2) dC 3 (22) where ( The above relationships show that of the 12 quantities 'Y, 9, X (or M), Z, 8, C" C 2 , C~, C), C~, C), 'T or X, only four are independent.…”

Control and monitoring of MSF-RO hybrid desalination process

“…The large scale (50,000 -75,000 m 3 /day) MSF brine recirculation (MSF-BR) plants are almost as cost efficient as reverse osmosis plants [7], but the smaller (27,000 -32,000 m 3 /day) conventional MSF plants are lagging in terms of cost efficiency. For RO plant water flux rate through the membrane increase with the feed water temperature due to decrease in the viscosity of the solution [8]. However, it also increases salt diffusion rate through membrane and also accelerate membrane degradation rate.…”

Analysis of Structural Characteristics of MGA-95 Membrane in Different Physical Conditions by X-Ray Scattering Method

“…Первой физической моделью, основанной на том, что мембрана состоит из кристаллических и аморф-ных областей, включающей в себя поровое пространство, через которое осущест-вляется перенос молекул и ионов в полупроницаемых мембранах, явилась капил-лярно-пористая гипотеза. Причем вода и растворенные вещества проникают не через кристаллические области, а проходят через аморфные области [1,2]. В зави-симости от размера аморфных областей полупроницаемых мембран изменяется степень проницания растворителя и растворенного вещества через мембрану.…”