Composite Anion Exchange Membranes Based on Quaternary Ammonium-Functionalized Polystyrene and Cerium(IV) Phosphate with Improved Monovalent-Ion Selectivity and Antifouling Properties

Membranes. 2023. Vol. 13. No. 7. Article 624.

Manin A., Golubenko D., Novikova S., Andrey Yaroslavtsev

The possibility of targeted change of the properties of ion exchange membranes by incorporation
of various nanoparticles into the membranes is attracting the attention of many research
groups. Here we studied for the first time the influence of cerium phosphate nanoparticles on
the physicochemical and transport properties of commercial anion exchange membranes based
on quaternary ammonium-functionalized polystyrenes, such as heterogeneous Ralex® AM and
pseudo-homogeneous Neosepta® AMX. The incorporation of cerium phosphate on one side of the
membrane was performed by precipitation from absorbed cerium ammonium nitrate (CAN) anionic
complex with ammonium dihydrogen phosphate or phosphoric acid. The structures of the obtained
hybrid membranes and separately synthesized cerium phosphate were investigated using FTIR,
P31 MAS NMR, EDX mapping, and scanning electron microscopy. The modification increased the
membrane selectivity to monovalent ions in the ED desalination of an equimolar mixture of NaCl
and Na2SO4. The highest selectivities of Ralex® AM and Neosepta® AMX-based hybrid membranes
were 4.9 and 7.7, respectively. In addition, the modification of Neosepta® membranes also increased
the resistance to a typical anionic surfactant, sodium dodecylbenzenesulfonate.

Keywords: selectivity, Ion exchange membranes, cerium phosphate, electrodialysis desalination, antifouling properties