Preparation of polyelectrolyte-modified membranes for heavy metal ions removal.

Polyethersulfone membranes were modified by polyelectrolyte (PE) multilayers, made of poly(allylamine hydrochloride) with poly(styrene sulfonate), to remove Cu, Zn and Ni heavy metal cations from aqueous solutions in a wide range of metal concentration (50-1200 ppm). After characterization of the modified membranes, the efficiency of the process was estimated for single heavy metal ions solution leading to high rejection rates (>90% for 50 ppm) and good adsorption capacities (7.0-8.

Functionalization of organic membranes by polyelectrolyte multilayer assemblies: application to the removal of copper ions from aqueous solutions.

The functionalization of an organic polyethersulfone membrane (PES) was performed by alternating deposition of poly(allylamine hydrochloride) (PAH) and poly(sodium 4-styrene sulfonate) (PSS), leading to the formation of a polyelectrolyte multilayer film (PEM). The resulting assembly was characterized by tangential streaming potential measurements to determine the charge of the modified membranes as a function of the polyelectrolyte solution concentration and as a function of the immersion time of the membrane in the polyelectrolyte solutions. Then, the modified membranes were used to perform the ultrafiltration of aqueous solutions containing copper(II) ions.

Characterization of an Al-, Ga-based catalyst by Ga NMR and XAS.

Both Nuclear Magnetic Resonance (NMR) and X-Ray absorption spectroscopies characterize local order around the observed nuclei. With the recent progresses of 71Ga solid state NMR, it has become possible to take advantage of the complementary information that can be obtained using these two methods. This opens the possibility of a more thorough description of the first coordination shells of Ga in oxide.