title: Chemical oxidation of a malodorous compound, indole, using iron entrapped in calcium alginate beads.
abstract: Iron-alginate beads (Fe-ABs) were successfully prepared by the ion-gelation method, and applied as heterogeneous Fenton catalysts for the removal of a malodorous compound 'indole'. Similarly, copper-enriched alginate beads (Cu-ABs) were synthesized and tested as like-Fenton catalyst, however, their application proved not to be effective for this purpose. Fe-ABs catalysts were characterized by FTIR, SEM, EDS and AAS spectroscopy. Results pointed out that the parameters affecting Fenton catalysis must be carefully chosen to avoid excessive iron release. Under optimal conditions, complete indole removal and considerably high reduction of TOC, without significant leaching was achieved. Indole decay followed a pseudo-first-order kinetics. The absolute rate constant for indole hydroxylation was 3.59×10(9) M(-1) s(-1), as determined by the competition kinetics method. Four reaction intermediates (Isatin, Dioxindole, Oxindole and Anthralinic acid) were identified by ULC/MS/MS analysis. Short-chain aliphatic carboxylic acids like formic, acetic, oxalic, maleic, oxamic and pyruvic acids were identified by ion exclusion chromatography and as end-products. Based on the identified by-products, a plausible mineralization pathway was proposed. Moreover, the catalyst was recovered quantitatively by simple filtration and reused for several times without significant loss of activity.
authors.affiliation: Laboratory of Analytical Chemistry and Electrochemistry, National Institute of Applied Sciences and Technology, Carthage University, Centre Urbain Nord B.P. No 676, 1080 Tunis Cedex, Tunisia. Electronic address: Samiabenhammouda@gmail.com.
authors.forename: Samia
authors.initials: S
authors.lastname: Ben Hammouda
authors.affiliation: Laboratory of Analytical Chemistry and Electrochemistry, National Institute of Applied Sciences and Technology, Carthage University, Centre Urbain Nord B.P. No 676, 1080 Tunis Cedex, Tunisia.
authors.forename: Nafaâ
authors.initials: N
authors.lastname: Adhoum
authors.affiliation: Laboratory of Analytical Chemistry and Electrochemistry, National Institute of Applied Sciences and Technology, Carthage University, Centre Urbain Nord B.P. No 676, 1080 Tunis Cedex, Tunisia.
authors.forename: Lotfi
authors.initials: L
authors.lastname: Monser
mesh_terms: D000327:Adsorption; D000464:Alginates / Q000737:chemistry*; D002264:Carboxylic Acids / Q000737:chemistry; D002384:Catalysis; D020723:Glucuronic Acid / Q000737:chemistry; D006603:Hexuronic Acids / Q000737:chemistry; D006861:Hydrogen Peroxide / Q000737:chemistry; D007211:Indoles / Q000737:chemistry*; D007501:Iron / Q000737:chemistry*; D009812:Odorants; D010084:Oxidation-Reduction; D014865:Waste Disposal, Fluid / Q000379:methods; D014874:Water Pollutants, Chemical / Q000737:chemistry*; D018508:Water Purification / Q000379:methods; D062367:ortho-Aminobenzoates / Q000737:chemistry
chemical_list: D000464:Alginates; D002264:Carboxylic Acids; D006603:Hexuronic Acids; D007211:Indoles; D014874:Water Pollutants, Chemical; D062367:ortho-Aminobenzoates; C031385:anthranilic acid; C030374:indole; D020723:Glucuronic Acid; D006861:Hydrogen Peroxide; D007501:Iron
keywords: Alginate beads; Fenton process; Malodorous compound; Supported catalyst