Removal of salts and dyes by low ZnAl2O4-TiO2 ultrafiltration membrane deposited on support made from raw clay

This paper reports the dynamic characterizations of a ZnAl2O4-TiO2 membrane deposited on a macroporous support prepared from Moroccan clay coated with a zirconia microfiltration interlayer. The water permeability of the membrane is 0.26 × 10−10 m s−1 Pa−1, its thickness is less than 700 nm with an average pore diameter of 5 nm, and a cut off about 4500 Da. The investigations of filtrations performed with different salts (NaCl, CaCl2, Na2SO4, CaSO4) prove the rejection mechanism is governed by a Donnan exclusion of the coion. Results obtained with solutions charged in heavy metal ions such as CrIII and synthetic dyes are very promising to consider the use of this membrane in depolluting filtration processes.