Several

of background cations on the fou membranes by natural organic matte g ev ois at is at U ber 20 r 2007 Adsorptiv matt investigated ques. important foulants through chemical analysis of two Midwestern surface waters. A model feed solution mimicking the lake waters and containing only NOM (Suwannee River NOM) and Ca2+ resulted in a fouling pattern similar to the surface waters; Mg2+ and Na+ caused much lower fouling at the same ionic strength as the calcium solution. Molecular modeling of the model solution allowed detailed probing of the fouling process. This work suggests that divalent ions (Ca2+ and Mg2+) may cause membrane fouling not by forming “ionic bridges ” between the negatively charged func molecules in not. Althoug with the carb is also man