Composite inorganic membranes containing nanoparticles of hydrated zirconium dioxide for electrodialytic separation
1 VI Vernadskii Institute of General & Inorganic Chemistry, Palladin Pr. 32/34, Kiev 03142, Ukraine
2 AN Frumkin Institute of Physical Chemistry & Electrochemistry, Leninskii Pr. 31, GSP-1, Moscow 119071, Russia
3 Institute of Macromolecular Chemistry of the NAS of Ukraine, Kharkivske sh., 48, Kiev 02000, Ukraine
Nanoscale Research Letters 2014, 9:271 doi:10.1186/1556-276X-9-271Published: 29 May 2014
The aim of the work was to elucidate the nature of charge-selective properties of macroporous composite inorganic membranes modified with nanoparticles of hydrated zirconium dioxide. The membranes have been investigated using methods of standard contact porosimetry, potentiometry, electron microscopy and small-angle X-ray scattering. The ion exchanger has been found to deposit inside pores of ceramics. Differential curves of pore volume distribution have been resolved using Lorentz functions; each maximum has been related to structure elements of the matrix and ion exchanger by means of calculations according to homogeneous and heterogeneous geometrical models. It was found that the voids, the radius of which is 4 to 8 nm, are responsible for charge selectivity of the composite membranes. These pores are formed due to blocking of macropores of ceramics with aggregates of nanoparticles of the ion exchanger; the radius of these aggregates is 20 to 24 nm. The membranes were applied to desalination of the solution containing NaCl. The removal degree of the salt from the solution reached 95% and 9% for the composite and unmodified membranes, respectively.