title: Simultaneous Cr(VI) reduction and non-ionic surfactant oxidation by peroxymonosulphate and iron powder.
abstract: Some industrial wastewaters contain both hexavalent chromium and surfactants. In this work, their removal from aqueous solution by zero-valent iron (ZVI) and peroxymonosulphate (PMS) was studied using Brij 35 as a representative non-ionic surfactant. The performance of the ZVI/PMS system in the simultaneous removal of both pollutants was compared to that achieved with control solutions containing either Cr(VI) or Brij 35 separately. Reactions were carried out over 24h at initial pH=2.3 with variable initial amounts of Cr(VI) and Brij 35. The results showed that surfactant removal was enhanced in the system also containing Cr(VI). Surfactant degradation followed zero-order kinetics and produced formic acid as the main by-product, together with hydroxylated aldehydes, formates and alcohols that were identified by LC/MS. The presence of surfactant similarly enhanced Cr(VI) reduction, which also followed zero-order kinetics. Chromium removal was quantitative only when the initial chromium concentration was lower than 140 mg L(-1). Reduced chromium was mainly in the solution phase together with dissolved iron. Precipitation with NaOH was therefore required to definitively remove dissolved metals from the investigated system.
authors.affiliation: Consiglio Nazionale delle Ricerche, Istituto di Ricerca Sulle Acque, Sezione di Bari, via Francesco De Blasio, 5, 70132 Bari, Italy. angela.volpe@ba.irsa.cnr.it
authors.forename: Angela
authors.initials: A
authors.lastname: Volpe
authors.forename: Michele
authors.initials: M
authors.lastname: Pagano
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Mascolo
authors.forename: Antonio
authors.initials: A
authors.lastname: Lopez
authors.forename: Ruggiero
authors.initials: R
authors.lastname: Ciannarella
authors.forename: Vito
authors.initials: V
authors.lastname: Locaputo
mesh_terms: D000438:Alcohols / Q000737:chemistry; D002851:Chromatography, High Pressure Liquid; D002857:Chromium / Q000737:chemistry*; D052918:Environmental Restoration and Remediation; D005561:Formates / Q000737:chemistry; D006863:Hydrogen-Ion Concentration; D007501:Iron / Q000737:chemistry*; D007700:Kinetics; D013058:Mass Spectrometry; D010084:Oxidation-Reduction; D010545:Peroxides / Q000737:chemistry*; D011092:Polyethylene Glycols / Q000737:chemistry; D013501:Surface-Active Agents / Q000737:chemistry*; D014874:Water Pollutants, Chemical / Q000737:chemistry*
chemical_list: D000438:Alcohols; D005561:Formates; D010545:Peroxides; D013501:Surface-Active Agents; D014874:Water Pollutants, Chemical; D002857:Chromium; C030544:formic acid; C074702:chromium hexavalent ion; C038288:peroxymonosulfate; D011092:Polyethylene Glycols; D007501:Iron; C515901:Brij 35