title: An assembled poly-4-vinyl pyridine and cellulose triacetate membrane and Bi2S3 electrode for photoelectrochemical diffusion of metallic ions.
abstract: The transport phenomena across ion exchange membrane may be enhanced by applying various strengths inside or outside the system. The electrical current, generated by n-type semiconductor, is used to catalyse the separation of metal ions. The cation exchange membrane located between the two compartments allows both the separation and concentration of M(n+) (Ag(+), Cu(2+), Pb(2+) and Ni(2+)). The flows of M(n+) from the aqueous solution to-and inside the membrane are monitored by the determination of the fluxes and the potentials. In this study, the four cations are investigated alone or in quaternary systems. From photoelectrochemical measurement, the gap of Bi(2)S(3) is found to be indirect at 1.65 eV. The shape of photocurrent potential curve and the negative flat band potential (-1.02 V(SCE)) give evidence of n-type character. The conduction band (-1.25 V(SCE)) yields thermodynamically M(2+) photoreduction and catalyzes the diffusion process. The photoelectrode Bi(2)S(3) makes the flux twofold greater than that observed in the dark. In all cases, the potential of the electrode M(2+)/M in the feed compartment increases until a maximal value, reached at approximately 100 min above which it undergoes a diminution. The membrane is more selective to Cu(2+) and this selectivity decreases in the quaternary system.
authors.affiliation: Laboratory of Hydrometallurgy and Molecular Inorganic Chemistry Faculty of Chemistry, USTHB, El Alia, 16111 Algiers, Algeria.
authors.forename: Mourad
authors.initials: M
authors.lastname: Amara
authors.forename: Omar
authors.initials: O
authors.lastname: Arous
authors.forename: Fatima
authors.initials: F
authors.lastname: Smail
authors.forename: Hacène
authors.initials: H
authors.lastname: Kerdjoudj
authors.forename: Mohamed
authors.initials: M
authors.lastname: Trari
authors.forename: Aissa
authors.initials: A
authors.lastname: Bouguelia
mesh_terms: D001729:Bismuth; D002482:Cellulose / Q000031:analogs & derivatives; D004058:Diffusion; D055664:Electrochemical Techniques / Q000295:instrumentation* / Q000379:methods* / Q000592:standards; D004566:Electrodes; D008567:Membranes, Artificial; D008670:Metals / Q000302:isolation & purification*; D055668:Photochemical Processes; D011145:Polyvinyls; D013440:Sulfides
chemical_list: D008567:Membranes, Artificial; D008670:Metals; D011145:Polyvinyls; D013440:Sulfides; C019535:poly(4-vinylpyridine); D002482:Cellulose; C024671:cellulose triacetate; D001729:Bismuth; C049897:bismuth sulfide