Modification of the Selectivity Properties of Tubular Ceramic Membranes after Alkaline Treatment
International audience; This work focuses on the selectivity modification of ceramic membranes after a mild alkaline treatment. Filtration of pure saltwater solutions was carried out with commercial titania membranes before and after the treatment. After treatment, the rejection of NaF significantly decreased, while the rejection of NaCl and NaBr increased. Additionally, NaI and Na 2 SO 4 remained close to zero. Pore size and electrical charge being almost unchanged, only significant modifications in the dielectric effects can explain this modification of selectivity. Therefore, the surface chemistry and the interaction (nature and magnitude) with the solvent and with the species present in…
Understanding the separation of anion mixtures by TiO2 membranes: Numerical investigation and effect of alkaline treatment on physicochemical properties
Abstract Mechanisms governing the rejection of ions from multi-ionic solutions, and especially the selectivity between various anions are not fully understood at the present time. In this study, it is proposed, in a first part, to investigate the evolution of electric and dielectric exclusion mechanisms when anions are mixed in a solution. For this purpose, the volumetric membrane charge Xd and the dielectric constant of the solution confined within pores ep are numerically assessed from rejection curves with a classic transport model. This study highlights that the rejection of the various anions is differently governed by electric and dielectric mechanisms but their contribution to mixtur…