title: A characterization study of some aspects of the adsorption of aqueous Co2+ ions on a natural bentonite clay.
abstract: The natural bentonite used in this study contained montmorillonite in addition to low cristobalite. The uptake of aqueous Co(2+) ions was investigated as a function of time, concentration, and temperature. In addition, the change in the interlayer space of montmorillonite was analyzed using XRPD, and the distribution of fixed Co(2+) ions on the heterogeneous clay surface was recorded using EDS mapping. The sorbed amount of Co(2+) appeared to closely follow Freundlich isotherm, with the sorption process showing apparent endothermic behavior. The relevance of the apparent DeltaH(o) values is briefly discussed. Analysis of the Co-sorbed bentonite samples using SEM/EDS showed that the montmorillonite fraction in the mineral was more effective in Co(2+) fixation than the cristobalite fraction. XRPD analysis demonstrated that the interlayer space of montmorillonite was slightly modified at the end of sorption.
authors.affiliation: Department of Chemistry, Izmir Institute of Technology, 35430 Urla, Izmir, Turkey. talalshahwan@iyte.edu.tr
authors.forename: T
authors.initials: T
authors.lastname: Shahwan
authors.forename: H N
authors.initials: HN
authors.lastname: Erten
authors.forename: S
authors.initials: S
authors.lastname: Unugur
mesh_terms: D000327:Adsorption; D000538:Aluminum Silicates; D001546:Bentonite / Q000737:chemistry; D055598:Chemical Phenomena; D002627:Chemistry, Physical; D000077215:Clay; D003035:Cobalt / Q000737:chemistry*; D003102:Colloids / Q000737:chemistry; D006358:Hot Temperature; D007477:Ions; D008855:Microscopy, Electron, Scanning; D012822:Silicon Dioxide / Q000737:chemistry; D013696:Temperature; D013816:Thermodynamics; D013997:Time Factors; D014867:Water / Q000737:chemistry; D014961:X-Ray Diffraction
chemical_list: D000538:Aluminum Silicates; D003102:Colloids; D007477:Ions; D014867:Water; D001546:Bentonite; D003035:Cobalt; D012822:Silicon Dioxide; D000077215:Clay