title: Cation exchange properties of zeolites in hyper alkaline aqueous media.
abstract: Construction of multibarrier concrete based waste disposal sites and management of alkaline mine drainage water requires cation exchangers combining excellent sorption properties with a high stability and predictable performance in hyper alkaline media. Though highly selective organic cation exchange resins have been developed for most pollutants, they can serve as a growth medium for bacterial proliferation, impairing their long-term stability and introducing unpredictable parameters into the evolution of the system. Zeolites represent a family of inorganic cation exchangers, which naturally occur in hyper alkaline conditions and cannot serve as an electron donor or carbon source for microbial proliferation. Despite their successful application as industrial cation exchangers under near neutral conditions, their performance in hyper alkaline, saline water remains highly undocumented. Using Cs(+) as a benchmark element, this study aims to assess the long-term cation exchange performance of zeolites in concrete derived aqueous solutions. Comparison of their exchange properties in alkaline media with data obtained in near neutral solutions demonstrated that the cation exchange selectivity remains unaffected by the increased hydroxyl concentration; the cation exchange capacity did however show an unexpected increase in hyper alkaline media.
authors.affiliation: Centre for Surface Chemistry and Catalysis, KU Leuven , Kasteelpark Arenberg 23 - box 2461, 3001 Heverlee, Belgium.
authors.forename: Leen
authors.initials: L
authors.lastname: Van Tendeloo
authors.forename: Benny
authors.initials: B
authors.lastname: de Blochouse
authors.forename: Dirk
authors.initials: D
authors.lastname: Dom
authors.forename: Jacqueline
authors.initials: J
authors.lastname: Vancluysen
authors.forename: Ruben
authors.initials: R
authors.lastname: Snellings
authors.forename: Johan A
authors.initials: JA
authors.lastname: Martens
authors.forename: Christine E A
authors.initials: CE
authors.lastname: Kirschhock
authors.forename: André
authors.initials: A
authors.lastname: Maes
authors.forename: Eric
authors.initials: E
authors.lastname: Breynaert
mesh_terms: D002411:Cation Exchange Resins / Q000737:chemistry; D002412:Cations / Q000737:chemistry*; D002586:Cesium / Q000737:chemistry; D006863:Hydrogen-Ion Concentration; D000068357:Saline Waters / Q000737:chemistry; D012996:Solutions; D014867:Water / Q000737:chemistry; D017641:Zeolites / Q000737:chemistry*
chemical_list: D002411:Cation Exchange Resins; D002412:Cations; D012996:Solutions; D014867:Water; D017641:Zeolites; D002586:Cesium