title: Liquid permeation and chemical stability of anodic alumina membranes.
abstract: A study on the chemical stability of anodic alumina membranes and their performance in long-term water and organic solvent permeation experiments is reported. Anodic alumina possesses high stability for both protonic and aprotonic organic solvents. However, serious degradation of the membrane occurs in pure water, leading to a drastic decrease of permeance (over 20% of the initial value after the passing of 0.250 m3/m2of pure water). The drying of the membrane induces further permeance drop-off. The rate of membrane degradation strongly depends on the pH of the penetrant solution and increases in basic media. According to27Al NMR and thermogravimetry results, the degradation of the membranes is associated with the dissolution of water-soluble [Al13O4(OH)24(H2O)12]7+polyhydroxocomplexes and their further redeposition in the form of [Al(OH)4]-, resulting in channels blocking. This process intensifies in basic pH due to the high positive charge of the anodic alumina surface. An approach for improving anodic aluminum oxide stability towards dissolution in water by carbon CVD coating of the membrane walls is suggested.
authors.affiliation: Department of Chemistry, Lomonosov Moscow State University, Moscow 119991 Leninskie hills 1-3, Russia; Department of Materials Science, Lomonosov Moscow State University, Moscow 119991 Leninskie hills, Russia.
authors.forename: Dmitrii I
authors.initials: DI
authors.lastname: Petukhov
authors.affiliation: Department of Materials Science, Lomonosov Moscow State University, Moscow 119991 Leninskie hills, Russia.
authors.forename: Dmitrii A
authors.initials: DA
authors.lastname: Buldakov
authors.affiliation: Department of Materials Science, Lomonosov Moscow State University, Moscow 119991 Leninskie hills, Russia.
authors.forename: Alexey A
authors.initials: AA
authors.lastname: Tishkin
authors.affiliation: Department of Chemistry, Lomonosov Moscow State University, Moscow 119991 Leninskie hills 1-3, Russia; Department of Materials Science, Lomonosov Moscow State University, Moscow 119991 Leninskie hills, Russia.
authors.forename: Alexey V
authors.initials: AV
authors.lastname: Lukashin
authors.affiliation: Department of Chemistry, Lomonosov Moscow State University, Moscow 119991 Leninskie hills 1-3, Russia; Department of Materials Science, Lomonosov Moscow State University, Moscow 119991 Leninskie hills, Russia.
authors.forename: Andrei A
authors.initials: AA
authors.lastname: Eliseev
keywords: anodic alumina; carbon-modified membranes; membrane stability; microfiltration membranes; ultrafiltration membranes