Effects of osmotic pressure and adsorption on ultrafiltration of ovalbumin

Abstract

The influence of osmotic pressure and solute adsorption on permeate flux during ultrafiltration of a solute that forms a gel-like layer on membrane surfaces was investigated. Ovalbumin solutions were ultrafiltrated using three different kinds of membranes, polyolefine, polysulfone, and polyacrylonitrile. Flux data were analyzed by three conventional models: gel polarization, osmotic pressure, and resistance in series.The experimental data were in conflict with all conventional models. Data analysis suggested that the main factors which influence permeate flux decline were osmotic pressure increase at the membrane surface and resistance caused by solute adsorption.A new model, which takes into account both osmotic pressure and resistance due to solute adsorption, is proposed. Permeate flux declines observed in the experiments fit this model quite precisely. The gel layer that forms on the membrane surface has little influence on permeate flux and can be neglected.

The role of adsorption on nanofiltration of azo dyes

“…Concentration polarization occurs due to the accumulation of solute that is being retained at the membrane interface. This results in a concentrated layer less permeable to the solvent associated to higher osmotic pressure ( π) at the membrane interface which leads to a decrease of the effective driving force [10].…”

“…For very dilute solutions (concentrations lower than 0.2 mol/l) of a single solute, the calculation of the osmotic pressure can be made by the van't Hoff equation [14]. For higher concentrations, the osmotic pressure, π, can be given by [10,15,16]:…”

“…In nanofiltration, flux is affected by concentration polarization or by fouling phenomena. Either contributes for a decrease of the driving force for the filtration leading to an increase of the osmotic pressure or increase of the resistance to the flux due to adsorption, pore blocking or solute deposition [10].…”

Confirmation of Free Solvent Model Assumptions in Predicting the Osmotic Pressure of Concentrated Globular Proteins

“…Several researchers have studied the osmotic pressure of ovalbumin at different solution conditions (5)(6)(7)(8). Bull and Breese measured the osmotic pressure of concentrated ovalbumin solution in 1 and 2 M salt solutions and at pH around the isoelectric point of ovalbumin (6).…”

【Original Contribution】 Long–term Durability of Desalination Performances of DynamicallyFormed Membranes Using Poly(acrylic acid) and Tubular Ceramic Supports

“…The difference between the membrane configurations was ignored by discussing the real rejection (Rreal), as defined: (2) (3) where C m , J v , and k are the concentration of the salt at the membrane surface, flux, and mass transfer coefficient, respectively. C m was calculated according to the concentration polarization equation 22,23) . k was obtained using the Deissler's equation.…”