Solute rejection by porous thin film composite nanofiltration membranes at high feed water recoveries

Removal of Cr(III) ions from salt solution by nanofiltration: experimental and modelling analysis

“…The equations (14) and (15) The membranes properties are usually determined by retention of ion i -R i (16) and permeate fl ux J P (17). (16) (17) where R i is the retention of ion i [%], c i,p is the concentration of ion in permeate [mol m -3 ], c i,w is the concentration of ion i in the feed [mol m -3 and characterized by pH ≈ 4 were investigated.…”

“…After analysing of the literatures data 15- 25 we have stated that both theoretical and experimental works concerning the ions separation mechanism into nanofi ltration membranes are not still satisfactory and require further actions. Recently the modelling of nanofi ltration of salt solution has been widely investigated [15][16][17][18][19][20][21][22][23][24][25] . The mass transfer through the membrane was described by different models such as Kedem-Katchalsky 19, 20 or Spiegler-Kedem 19, 21, 25 .…”

Nanofiltration – Theory and Application

“…For binary salt solutions (e.g., NaCl only) at fi xed pH, rejection primarily depends on the effective membrane pore size (due to steric effects), the ratio of membrane charge density to salt concentration, and permeate fl ux [21,22]. In general, ion rejection increases with increasing ion size and decreasing effective pore radius (steric effect), increasing salt valence (Donnan exclusion), decreasing salt concentration for a fi xed membrane surface charge (Donnan exclusion, Figure 4.2), and increasing permeate fl ux.…”

“…This approach is often described as a 'black-box' model as the two model coeffi cients (σ and P) encompass the structural and electrical properties of the membrane and solute that infl uence rejection. Recently, Sharma and Chellam [21] used the phenomenological model to predict the removal of organic matter and salts by NF treatment of surface water at high system recoveries. For example, describing salt rejection by NF requires characterization of σ and P through experimentation and model fi tting with the water matrix and membrane of interest.…”

Prediction of The Chromium (III) Separation From Acidic Salt Solutions On Nanofiltration Membranes Using Donnan And Steric Partitioning Pore (DSP) Model

“…According to the literature data [5,7,8] and our own investigations [6,9], one of the most important and interesting research area of nanofiltration is separation of chromium (III) from acidic salt solutions. The nanofiltration membrane in such processes, according to its properties, becomes non-permeable for multi-charged ions and permeable for one-charged anions and cations [10][11][12]. That is why nanofiltration seems to be a promising process allowing for effective and efficient treatment of chromium tannery wastewater [5,6,8].…”