title: Adsorption of Cr(VI) from synthetic solutions and electroplating wastewaters on amorphous aluminium oxide.
abstract: The adsorption behaviour of amorphous aluminium oxide was studied with respect to Cr(VI) in order to consider its application to purify electroplating wastewaters. A batch method was employed using Cr(VI) concentrations ranged from 10 to 200mg/l. The Langmuir model was found to describe the adsorption process well, offering a maximum adsorption capacity of 78.1mg/g. The effect of ionic strength (0-0.1M KNO(3)), pH (3-9) and competitive solutes (molar ratio [Cr(VI)]/[SO(4)(2-)]=1 and 100) on the retention process was evaluated. Cr(VI) adsorption on amorphous aluminium oxide appeared to be dependent on ionic strength with a more pronounced effect in acid conditions. Conversely, adsorption was not affected by pH in acid medium, but decreased when pH sifted to alkaline values. The presence of SO(4)(2-) greatly reduced Cr(VI) removal across the entire pH range when both solutes were present in similar concentrations. Amorphous aluminium oxide also showed a high adsorption capacity when used in the purification of Cr(VI) electroplating wastewaters. The adsorbent doses required to attain more than 90% of Cr(VI) removal varied between 1 and 5 g/l depending on Cr(VI) concentration in wastewaters.
authors.affiliation: Institute of Earth Sciences Jaume Almera (CSIC), C/ Lluís Solé i Sabarís, s/n, 08028 Barcelona, Spain. ealvarez@ija.csic.es
authors.forename: E
authors.initials: E
authors.lastname: Alvarez-Ayuso
authors.forename: A
authors.initials: A
authors.lastname: García-Sánchez
authors.forename: X
authors.initials: X
authors.lastname: Querol
mesh_terms: D000327:Adsorption; D000537:Aluminum Oxide / Q000737:chemistry*; D002857:Chromium / Q000737:chemistry*; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D012996:Solutions; D013816:Thermodynamics; D014874:Water Pollutants, Chemical
chemical_list: D012996:Solutions; D014874:Water Pollutants, Chemical; D002857:Chromium; D000537:Aluminum Oxide