Heterogeneous Membranes Modified with Nanoparticles of Inorganic Ion-Exchangers for Whey Demineralization

Composite materials were obtained by modification of polymer ion exchange membranes with nanoparticles of zirconium hydrophosphate and hydrated zirconium dioxide. Empirical parameters related to porosity of the membranes and ion transport were proposed. Nanoparticles (4-20 nm) in clusters and channels of ion exchange polymer improve transport of counter-ions: transport number of cations increases from 0.46 to 0.78 under limiting current. The aggregates in non-transport pores are a barrier against organic matters. The composites were applied to whey electrodialysis. Current efficiency reaches 97% for K+, Na+, Ca2+, Mg2+ cations and 11-22% for HPO42− and H2PO4− anions.