Pressure Retarded Osmosis and Forward Osmosis Membranes: Materials and Methods

Abstract

Abstract:In the past four decades, membrane development has occurred based on the demand in pressure driven processes. However, in the last decade, the interest in osmotically driven processes, such as forward osmosis (FO) and pressure retarded osmosis (PRO), has increased. The preparation of customized membranes is essential for the development of these technologies. Recently, several very promising membrane preparation methods for FO/PRO applications have emerged. Preparation of thin film composite (TFC) membranes with a customized polysulfone (PSf) support, electorspun support, TFC membranes on hydrophilic support and hollow fiber membranes have been reported for FO/PRO applications. These novel methods allow the use of other materials than the traditional asymmetric cellulose acetate (CA) membranes and TFC polyamide/polysulfone membranes. This review provides an outline of the membrane requirements for FO/PRO and the new methods and materials in membrane preparation.

Forward Osmosis as a Pre-Treatment Step for Seawater Dilution and Wastewater Reclamation

“…Forward osmosis has inherent potential advantages that highlight it as a promising alternative to pressure-driven membrane separation technologies [16]. These advantages include low energy consumption due to minimal or non-use of external hydraulic pressure.…”

“…Several advantages make the forward osmosis process a more attractive alternative compared to other techniques and they include low energy utilization, lower membrane fouling propensity, simplicity as well as the good rejection of a wide variety of foulants compared to pressure-driven membrane processes [13,15]. The forward osmosis can also be fitted as an additional step to pressure-driven processes resulting in hybrid processes with potentially improved water recovery and energy savings [16,17].…”

Investigation of pressure retarded osmosis power production

“…[5] It is clear from equation (1) that if ΔP=0 we have direct osmosis (DO), for which J w =A Δπ. However if 0<ΔP<Δπ we have Pressure Retarded Osmosis (PRΟ), so defined because the direction of permeation flux is still the same as in direct osmosis but the flux is decreased as the hydraulic pressure increases (in contrast to reverse osmosis (RO), a well developed technology, for which ΔP>Δπ and in which an increase in ΔP increases the flux).…”

Modification of Nanofiber Support Layer for Thin Film Composite Forward Osmosis Membranes via Layer-By-Layer Polyelectrolyte Deposition

“…Selectively permeable asymmetric cellulose acetate membrane was prepared by Sidney Loeb and Srinivasa Sourirajan in 1963, providing a breakthrough in reverse osmosis processes and membrane science [6]. However, membranes were fabricated more for application to RO rather than FO and pressure retarded osmosis (PRO).…”