Boron transport in forward osmosis: Measurements, mechanisms, and comparison with reverse osmosis

Removal of dissolved organics from produced water by forward osmosis

“…If the porous support layer on the FO membrane faces the feed solution, a polarized layer is established along the inside of the dense active layer and solute propagates to the porous layer. Referred to as concentrative internal CP [32][33], this phenomenon is similar to the concentrative external CP, except that it takes place within the porous layer and cannot be minimized by cross flow. When the feed solution is against the active layer and the draw solution is against the supporting layer, the ICP phenomenon occurs on the permeate side.…”

A novel analysis of reverse draw and feed solute fluxes in forward osmosis membrane process

“…Typical bench-scale crossflow RO and FO systems were used in this study, and their schematic diagrams can be found elsewhere [8][9][10]. The membrane cells in both systems had the same geometry, except that the FO cell had two symmetric channels on both sides of the membrane for co-current flows of the feed and draw solutions.…”

“…Under this condition, water and NaCl solutes move across the FO membrane in the same direction, from feed to draw side. The selection of dextrose for draw solutes was made to prevent draw solutes from interfering and/or hindering feed solute transport, since dextrose molecules hardly diffuse from the support to the active layer due to their large hydrated radius [8,9]. As shown in Fig.…”

“…Such examples include microfiltration (MF) and ultrafiltration (UF) for membrane bioreactors in wastewater treatment [2] and for pre-treatments in seawater desalination [3] as well as nanofiltration (NF) and reverse osmosis (RO) in brackish water [4] and seawater desalination [5][6][7]. The forward osmosis (FO) process has also been attracting great attention for its potential applications in seawater desalination [8,9], wastewater reclamation [10,11], and industrial wastewater treatment such Desalination 352 (2014) 128-135 as shale gas produced wastewater [12][13][14]. Particularly, in terms of membrane fouling/cleaning, FO process is assumed to be more preferable to RO process [9,10,[15][16][17][18].…”

“…Firstly, the parameters related to the active layer of the FO membrane (i.e., A and B) are measured by applying hydraulic pressure in RO mode experiments. Subsequently, the support layer structural parameter (S) is determined by a FO mode experiment which uses osmotic pressure as the driving force [8,16,19]. In addition, the measurements made in pressure retarded osmosis (PRO) mode experiments, with the draw solution facing the active side of the membrane, may be used to complement or substitute those made in FO mode experiments [20,21].…”