title: Synthesis of a red iron oxide/montmorillonite pigment in a CO2-rich brine solution.
abstract: The homoionic calcium-montmorillonite was used to synthesize a red iron oxide/clay pigment in a CO2-rich brine solution (0.5 M of NaCl) by using an agitated batch-reactor (engineer autoclave). The operating conditions were 15 days of reaction, 200 bars of pressure and 150 degrees C of temperature. SEM/EDS, STEM/EDS, XRD and Infrared Spectrometry were performed to characterize before and after reaction the solid phase. The results showed the precipitation of spherical nanoparticles (50-500 nm) of iron oxide (Fe2O3) dispersed and/or coagulated in the clay-matrix. Evidently, this oxide produced red coloration in the final product. For this case, the Fe3+ cation was provided to the aqueous solution by the dissolution of Ca-montmorillonite, particularly, the dissolution of most fine particles contained in the starting clay material. The cation exchange process and precipitation of polymorph silica were also observed.
authors.affiliation: UMR-G2R 7566 UHP-CNRS-INPL-CREGU, BP 239, 54506 Vandoeuvre-les-Nancy Cedex, France. german.montes@g2r.uhp-nancy.fr
authors.forename: G
authors.initials: G
authors.lastname: Montes-Hernandez
authors.forename: J
authors.initials: J
authors.lastname: Pironon
authors.forename: F
authors.initials: F
authors.lastname: Villieras
mesh_terms: D001546:Bentonite / Q000138:chemical synthesis* / Q000737:chemistry; D002118:Calcium / Q000737:chemistry*; D002245:Carbon Dioxide / Q000737:chemistry*; D004396:Coloring Agents / Q000138:chemical synthesis* / Q000737:chemistry; D005290:Ferric Compounds / Q000138:chemical synthesis* / Q000737:chemistry; D008855:Microscopy, Electron, Scanning; D046529:Microscopy, Electron, Transmission; D012492:Salts / Q000737:chemistry*; D012996:Solutions / Q000737:chemistry
chemical_list: D004396:Coloring Agents; D005290:Ferric Compounds; D012492:Salts; D012996:Solutions; C017082:brine; D001546:Bentonite; D002245:Carbon Dioxide; C000499:ferric oxide; D002118:Calcium