Nanocomposites and nanomaterials

Membranes modified with nanocomposites of hydrated zirconium dioxide and oxidized graphene
Rozhdestvenska L.M.1, Kudelko K.O.1, Ogenko V.M.1, Kolomiyets E.O.1, Plisko T.V.2, Bildyukevich O.V.2, СhmilenkoV.V.3, Borisenko Y.V.3
1 V.I. Vernadskii Institute of General and Inorganic Chemistry of the NAS of Ukraine, 32/34 Palladin ave., 03142 Kyiv, Ukraine
E-mail: kolomiyetsy@gmail.com
2 Institute  of  Physical-Organic  Chemistry, NAS  of  Belarus,  Surganov str. 13, 220072 Minsk, Belarus
3 Kyiv  National  University  of  Technologies  and Design of the MES of  Ukraine, Nemyrovych-Danchenko str. 2, 01011 Kyiv, Ukraine

Organіс- inorganic  membranes  were  obtained  by impregnating  ultrafiltration  membranes  with  a composite  modifier  -  hydrated zirconium (IV) dioxide (HZD) containing  oxidized  graphene  (GO, 0.5  wt.%).  The  modifier  was  precipitated  in  the  active  layer  of the membrane forming a "secondary active layer".  The  layer  thickness  calculated  according to  the   Kozeny-Carman   equation  is  0.66-1.38 μm. A thinner layer is formed  in  the  membrane with  smaller  pore  size, which is identified according to the rejection of calibrant (polyvinylpyrrolidone, molexular mass of which is 40 kDa). The  diffusion  coefficients of Li+ and Na+ ions  were  determined, the effect of HZD and HZD-GO composite on the ion transport was discussed. The influence of  the  modifier  on  the  retention  ability  relatively  to  hardness  ions  (10-14%)  and  to  protein compounds  (95-98%)  was established. The mathematical  modeling  of  the  dependence  of  the  permeate  flux  versus  time  showed  that the  ion  exchanger  particles  in  the polymer  active  layer  prevents  the  accumulation of organic  substances  in  pores.  Therefore, only  the  outer  surface  of  the membrane is contaminated, and the precipitate  can be easily removed mechanically. It was shown that the insertion of  GO into pores of  the  membranes is  advisable  only  in  the  case  of  a finely porous active layer. In particular, the performance  of the initial  polymer  membrane  (20 dm3 m-3 h-1) and  the  selectivity to  the  calibrant of  40  kDa (99%)  is  the criteria of the choice of polymer matrix.  In  comparison  with  a  membrane  modified  only with  inorganic  ion-exchanger, the membrane containing GO shows high filtration rate of protein solutions and  considerable resistance against contamination. The results are discussed from the point of view of hydrophilic-hydrophobic properties of composite membranes.