ELECTROKINETIC CHARACTERIZATION OF POLYETHERSULFONE UF MEMBRANES

The streaming potential and permeate flux of polyethersulfone organic membranes were determined during the filtration of solutions having va rious compositions. The permeate flux is only marginally affected by p H variations or the nature and concentration of species in solution. S treaming potential measurements for membranes having 20 and 100 kDa cu t-off values give isoelectric points of respectively 2.4 and 2.2. The specific adsorption of divalent ions leads to a decrease in the stream ing potential for a given ionic strength and pH. The zeta potential wa s determined from previous results using the Helmoltz-Smoluchowski rel ation. It leads to results that are incompatible with the classic theo ry because this relation does not take into account the double layer o verlapping which occurs in the pore. Corrections made to take into acc ount this phenomenon lead to more satisfactory results.