title: Dye adsorption onto mesoporous materials: pH influence, kinetics and equilibrium in buffered and saline media.
abstract: Mesoporous materials were used as adsorbents for dye removal in different media: non-ionic, buffered and saline. The mesoporous materials used were commercial (silica gel) as well as as-synthesised materials (SBA-15 and a novel mesoporous carbon). Dye adsorption onto all the materials was very fast and the equilibrium was reached before 1 h. The pH has a significant influence on the adsorption capacity for the siliceous materials since the electrostatic interactions are the driving forces. However, the influence of the pH on the adsorption capacity of the carbonaceous material was lower, since the van der Waals interactions are the driving forces. The ionic strength has a great impact on the siliceous materials adsorption capacity, being their adsorption capacity in a buffered medium six times higher than the corresponding to a non-ionic medium. Nevertheless, ionic strength does not influence on the dye adsorption on the mesoporous carbon. Overall, the as-synthesised carbon material presents a clear potential to treat dye effluents, showing high adsorption capacity (q(e) ≈ 200 mg/g) in all the pH range studied (from 3 to 11); even at low concentrations (C(e) ≈ 10 mg/L) and at short contact times (t(e) < 30 min).
authors.affiliation: Chemical Engineering Department, CyPS Group, Complutense University of Madrid, Avda. Complutense s/n, 28040 Madrid, Spain. Electronic address: segojmgm@ucm.es.
authors.forename: J M
authors.initials: JM
authors.lastname: Gómez
authors.affiliation: Chemical Engineering Department, CyPS Group, Complutense University of Madrid, Avda. Complutense s/n, 28040 Madrid, Spain.
authors.forename: J
authors.initials: J
authors.lastname: Galán
authors.affiliation: Chemical Engineering Department, CyPS Group, Complutense University of Madrid, Avda. Complutense s/n, 28040 Madrid, Spain.
authors.forename: A
authors.initials: A
authors.lastname: Rodríguez
authors.affiliation: School of Chemistry and Chemical Engineering, Queen's University of Belfast, David Keir Building, Stranmillis Road, Belfast BT9 5AG, UK; Materials Surface Science Institute, Department of Chemical and Environmental Sciences, University of Limerick, Ireland.
authors.forename: G M
authors.initials: GM
authors.lastname: Walker
mesh_terms: D000327:Adsorption; D002021:Buffers; D002244:Carbon / Q000737:chemistry; D004396:Coloring Agents / Q000737:chemistry*; D006801:Humans; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D010316:Particle Size; D012822:Silicon Dioxide / Q000737:chemistry; D012965:Sodium Chloride
chemical_list: D002021:Buffers; D004396:Coloring Agents; C509969:SBA-15; D012965:Sodium Chloride; D002244:Carbon; D012822:Silicon Dioxide
keywords: Adsorption; Buffer; Dye; Ionic strength; Mesoporous