Analysis of membrane fouling in the treatment of water solutions containing humic acids and mineral salts

Reduction of disinfection by-products precursors by nanofiltration process

“…For tannic acid with medium MW, at pH values lower than its ionization constant, the molecule is neutral and may form a compact and coiled conformation because of the suppression of dissociation of ionogenic groups. Kabsch-Korbutowicz et al [19] conducted a similar investigation for the humic and fulvic acids and found the same result as this study. The suppression effect leads to a restriction of electrostatic intra-chain repulsion and thus a reduction in the tannic acid molecular size under acidic conditions.…”

“…Hardness in source water may introduce calcium which may interfere with the removals of DBPs. The fate of NOM in source water may be affected by the following physical chemical processes: binding, transport, and deposition of organic and inorganic pollutants [19]. A thorough understanding of the rejection mechanisms of DBP precursors and performance of NF membrane is necessary to determine the proper type of membrane to be used for the removals of DBPs and the prediction of rejection.…”

Humic acid fouling in the membrane distillation process

“…The cake layer was then formed on the region which had been blocked. The deterioration of permeation flux during the ultrafiltration of humic acids was studied by Kabsch-Korbutowicz et al [8]. They reported that the membrane with a higher degree of hydrophilicity was the least affected.…”

“…The significant flux decline at low pH was attributed to the thick humie acid deposit layer contributed by the reduction of electrostatic repulsion between humic acid molecules and the strong tendency to sorption on the membrane surface [8,9]. Similarly, at high ionic strength, the increase in fouling was due to the tightly packed, and low permeable deposit caused by the increased electrostatic shielding among the charged humic acid molecules [4,9].…”

“…Similarly, at high ionic strength, the increase in fouling was due to the tightly packed, and low permeable deposit caused by the increased electrostatic shielding among the charged humic acid molecules [4,9]. The presence of multivalent ions increased the rate of flux decline and lowered the steady-state flux due to charge screening and complex formation [6,8].…”