Chromium VI adsorption on cerium oxide nanoparticles and morphology changes during the process.
In this study, suspended cerium oxide nanoparticles stabilized with hexamethylenetetramine were used for the removal of dissolved chromium VI in pure water. Several concentrations of adsorbent and adsorbate were tested, trying to cover a large range of possible real conditions. Results showed that the Freundlich isotherm represented well the adsorption equilibrium reached between nanoparticles and chromium, whereas adsorption kinetics could be modeled by a pseudo-second-order expression. The separation of chromium-cerium nanoparticles from the medium and the desorption of chromium using sodium hydroxide without cerium losses was obtained. Nanoparticles agglomeration and morphological changes during the adsorption-desorption process were observed by TEM. Another remarkable result obtained in this study is the low toxicity in the water treated by nanoparticles measured by the Microtox(®) commercial method. These results can be used to propose this treatment sequence for a clean and simple removal of drinking water or wastewater re-use when a high toxicity heavy metal such as chromium VI is the responsible for water pollution.
Recillas
Sonia
S
Department of Chemical Engineering, Engineering School, Autonomous University of Barcelona, 08193 Bellaterra, Spain.
Colón
Joan
J
Department of Chemical Engineering, Engineering School, Autonomous University of Barcelona, 08193 Bellaterra, Spain.
Casals
Eudald
E
Catalan Institute of Nanotechnology, Autonomous University of Barcelona Campus, 08193 Bellaterra, Spain.
González
Edgar
E
Catalan Institute of Nanotechnology, Autonomous University of Barcelona Campus, 08193 Bellaterra, Spain.
Puntes
Victor
V
Catalan Institute of Nanotechnology, Autonomous University of Barcelona Campus, 08193 Bellaterra, Spain; Catalan Institute of Research and Advanced Studies, Passeig Lluís Companys, 23, 08010 Barcelona, Spain.
Sánchez
Antoni
A
Department of Chemical Engineering, Engineering School, Autonomous University of Barcelona, 08193 Bellaterra, Spain. Electronic address: antoni.sanchez@uab.cat.
Font
Xavier
X
Department of Chemical Engineering, Engineering School, Autonomous University of Barcelona, 08193 Bellaterra, Spain.
D000327:Adsorption; D002563:Cerium / Q000737:chemistry*; D002857:Chromium / Q000737:chemistry*; D007700:Kinetics; D053768:Metal Nanoparticles; D046529:Microscopy, Electron, Transmission; D008962:Models, Theoretical; D010316:Particle Size; D013816:Thermodynamics; D014961:X-Ray Diffraction
D002857:Chromium; D002563:Cerium; C030583:ceric oxide