title: Box-Behnken experimental design for chromium(VI) ions removal by bacterial cellulose-magnetite composites.
abstract: In this study bacterial cellulose-magnetite composites were synthesised for the removal of chromium(VI) from aqueous solutions. Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), thermogravimetric analysis and X-ray Photoelectron Spectroscopy (XPS) were used to characterize the bacterial cellulose-magnetite composites and to reveal the uniform dispersion of nanomagnetite in the BC matrix. Magnetic properties were also measured to confirm the magnetite immobilization on bacterial cellulose membrane. The effects of initial Cr(VI) concentration, solution pH and solid/liquid ratio upon chromium removal were examined using the statistical Box-Behnken Design. Because of the possibility of magnetite dissolution during chromium(VI) adsorption, the degree of iron leaching was also analysed in the same conditions as Cr(VI) adsorption. From the factors affecting chromium(VI) adsorption the most important was solution pH. The highest Cr(VI) removal efficiency was observed at pH 4, accompanied by the lowest iron leaching in the solution. The adsorption experiments also indicated that the adsorption process of chromium(VI) is well described by Freundlich adsorption model. Our results proved that the BC-magnetite composites could be used for an efficient removal of chromium(VI) from diluted solutions with a minimum magnetite dissolution during operation.
authors.affiliation: University "Politehnica" of Bucharest, Faculty of Applied Chemistry and Materials Science, 1-3 Polizu Street, Bucharest 011061, Romania.
authors.forename: Anicuta
authors.initials: A
authors.lastname: Stoica-Guzun
authors.affiliation: University "Politehnica" of Bucharest, Faculty of Applied Chemistry and Materials Science, 1-3 Polizu Street, Bucharest 011061, Romania. Electronic address: marta_stroescu@yahoo.com.
authors.forename: Marta
authors.initials: M
authors.lastname: Stroescu
authors.affiliation: University "Politehnica" of Bucharest, Faculty of Applied Chemistry and Materials Science, 1-3 Polizu Street, Bucharest 011061, Romania.
authors.forename: Sorin Ion
authors.initials: SI
authors.lastname: Jinga
authors.affiliation: University of Bucharest, Faculty of Chemistry, 4-12 Bd. Regina Elisabeta, Bucharest, Romania.
authors.forename: Nicoleta
authors.initials: N
authors.lastname: Mihalache
authors.affiliation: Research and Development National Institute for Metals and Radioactive Resources, 70 Bd. Carol I, Bucharest 020917, Romania.
authors.forename: Adriana
authors.initials: A
authors.lastname: Botez
authors.affiliation: University "Politehnica" of Bucharest, Faculty of Applied Chemistry and Materials Science, 1-3 Polizu Street, Bucharest 011061, Romania.
authors.forename: Cristian
authors.initials: C
authors.lastname: Matei
authors.affiliation: University "Politehnica" of Bucharest, Faculty of Applied Chemistry and Materials Science, 1-3 Polizu Street, Bucharest 011061, Romania.
authors.forename: Daniela
authors.initials: D
authors.lastname: Berger
authors.affiliation: University "Politehnica" of Bucharest, Faculty of Applied Chemistry and Materials Science, 1-3 Polizu Street, Bucharest 011061, Romania.
authors.forename: Celina Maria
authors.initials: CM
authors.lastname: Damian
authors.affiliation: University "Politehnica" of Bucharest, Faculty of Electrical Engineering, 313 Spl. Independentei Street, 060042 Bucharest, Romania.
authors.forename: Valentin
authors.initials: V
authors.lastname: Ionita
mesh_terms: D000327:Adsorption; D002482:Cellulose / Q000737:chemistry*; D002857:Chromium / Q000737:chemistry* / Q000302:isolation & purification*; D052203:Ferrosoferric Oxide / Q000737:chemistry*; D041821:Gluconacetobacter / Q000737:chemistry*; D007700:Kinetics; D060328:Magnetic Phenomena; D014867:Water / Q000737:chemistry; D014874:Water Pollutants, Chemical / Q000737:chemistry* / Q000302:isolation & purification*; D018508:Water Purification
chemical_list: D014874:Water Pollutants, Chemical; D014867:Water; D002857:Chromium; C074702:chromium hexavalent ion; D002482:Cellulose; D052203:Ferrosoferric Oxide
keywords: Adsorption; Bacterial cellulose-magnetite; Chromium(VI)