A method for characterizing membranes during nanofiltration at extreme pH

Separation of 3′-sialyllactose and lactose by nanofiltration: A trade-off between charge repulsion and pore swelling induced by high pH

“…This is further supported by the decrease in permeate flux for the ETNA01PP membrane observed at pH 10, presumably caused by the increase in osmotic pressure resulting from the increased retention For the tighter membrane NF45, no effect on rejection is seen when changing the pH. This is in accordance with previous findings by Dalwani et al [22], who shows that for a similar tight polyamide membrane changes in pore size are only observed when pH exceeds 10. A drop in lactose rejection as a result of the likely pore swelling was not detected since lactose retention levels were already very low (>20%).…”

A novel cellulose/chitosan composite nanofiltration membrane prepared with piperazine and trimesoyl chloride by interfacial polymerization

“…Usually, the M w of the solute corresponding to a retention rate of 90% on the retention curve is dened as the MWCO of a membrane. 19,20 The experiment measured the retention performance of the solution to characterize the MWCO of the membrane by measuring PEGs of different M w (M w ¼ 400, 600, 800, 1000, and 2000 Da). The concentration of PEG was determined by employing the chromogenic reaction method between PEG and iodine, which was determined from the UV-Vis spectrophotometry.…”

Molecular weight cut-off determination of organic solvent nanofiltration membranes using poly(propylene glycol)

“…In aqueous solutions, a number of methods have been developed to determine the MWCO of a NF membrane. [6,[8][9][10] However, these methods cannot be directly applied for use in organic solvent systems due to various issues such as solute solubility and compatibility in organic solvents, as well as the numerous and complex solute-solvent-membrane interactions present. Suitable techniques for determining the concentration of the probe molecule in the permeate is also problematic when applied across a range of solvents.…”