Characterization of nanofiltration membranes

A novel method for fabricating composite mosaic membrane with unique NF selectivity

“…3d also implies that retention difference between identically charged solutes such as xylenol orange and 1-nitroso-2-naphthol-3,6-disulphonic sodium salt depends on size effect, that is, the solute with larger molecular weight has higher retention than that with smaller molecular weight. These experimental results suggest that steric (sieving) effect and Donnan effect might be the main factors controlling dye permeation in the membranes (Peeters, 1997;He et al, 2002).…”

“…Figures 3b and 3d show that the membrane can pass almost all the electrolytes, but significantly reject the dyes. These characteristics of membrane retention exhibit the functions of the mosaic structure, highly different from both the conventional negatively charged NF membranes (whose retention to Na 2 SO 4 is normally greater than 90%) and the positively charged NF membranes (whose retention to MgCl 2 is normally greater than 90% ) (Peeters, 1997). Although the membrane prepared in the present study contains both positively and negatively charged groups, it is quite difficult to fabricate an ideal charged mosaic membrane, with the capacity of the negatively charged groups exactly the same as that of the positively charged groups.…”

“…Most of these processes are quite complicated and time consuming. Although numerous studies have been conducted on composite membranes via interfacial polymerization, however, most of them were limited to the preparation of reverse osmosis (RO) membranes or conventional NF membranes (Peeters, 1997;Morgan, 1965). The trial fabrication of a charged mosaic composite membrane by interfacial polymerization has not been reported yet.…”

Size and Charge Effects on Crossover of Flow Battery Reactants Evaluated by Quinone Permeabilities Through Nafion

“…a sulfonated quinone in Nafion) may be approximated by considering the concentration of membrane fixed charges and the condition of electroneutrality, without involving any other membrane properties (Supplementary Note 2). 9,33 To fulfill this condition, the co-ion concentration in the membrane phase must be lower than in the contacting electrolyte: this is the Donnan exclusion effect. The effect is strengthened when the valence of co-ions is higher, such that fewer dianions (e.g.…”

Membrane fouling in waste water filtration: causes, consequences and prevention

“…In order to investigate the outer surface charges of membranes, streaming potential measurements were carried out by the same method and set-up as was described by Peeters (Peeters, 1997) -Different electrolyte concentrations of 10-5 to 10-1 M KCl. (Merck pro analysis) were used.…”