MIEX resins, a three-dimensional structure with polymeric chains,
which have electrically charged functional groups located on the
chains and different charged ions (counter-ions) attached to the
functional groups through electrostatic forces, could remove the ions
in the raw water by ion exchange [62], and can exchange weak
organic acid ions from a pH around 7.0 due to its strong base
functionality [63–65]. Kabsch-Korbutowicz et al. [27] compared the
efficacy of coagulation and MIEX resin adsorption as a pretreatment of
ultrafiltration, and reported that both of the pretreatment methods
could increase the permeate quality and decrease the membrane
fouling. Importantly, MIEX resin could remove organic matter more
effectively than coagulation due to its ability for the removal of lowmolecular
fractions, which is claimed by Lee et al. [17] as a main
foulant to the UF membrane. However, there is a lack of data about the
pilot-scale or large-scale of MIEX as a pretreatment option for
ultrafiltration of various source waters, so more studies are needed
to better understand the mechanism of MIEX on fouling of ultrafiltration.
Besides, due to the higher cost, the research and application
of MIEX are more popular in developed countries than developing
countries.