title: Adsorption/desorption of linear alkylbenzenesulfonate (LAS) and azoproteins by/from activated sludge flocs.
abstract: Our study investigated the adsorption/desorption by/from activated sludge flocs, dispersed in river water or in diluted wastewater, of organic compounds (C(11)-LAS, azoalbumin and azocasein) at concentrations relevant to environmental conditions. Activated sludge flocs, used as a model of biological aggregates, are characterized by a very heterogeneous matrix able to sorb the three organic compounds tested at 4 degrees C. The adsorbed amount of C(11)-LAS by activated sludge flocs was higher than that of azocasein or azoalbumin, as shown by the Freundlich parameters (K(ads)=8.6+/-1.7, 1.6+/-0.3 and 0.3+/-0.1 micromol(1-1/n)g(-1)l(1/n) for C(11)-LAS, azocasein and azoalbumin, respectively; n=3 sludges). C(11)-LAS sorption from activated sludge appeared to be partially reversible in river water, while a marked hysteresis phenomenon was observed for azocasein and azoalbumin, implying a low degree of reversibility in their exchange between activated sludge and river water. It has also been displayed that the conductivity variation of bulk water (comprised between 214 and 838 microS cm(-1)) exerted no dramatic effect on the C(11)-LAS desorption from activated sludge flocs, while a little effect of it on azocasein desorption was observed. Thus, biological aggregates as activated sludge flocs can serve as an intermediate carrier for C(11)-LAS, while it represents a sink for proteins.
authors.affiliation: LCPME, UMR 7564 CNRS-Université Henri Poincaré Nancy 1, Faculté de Pharmacie, Pôle de l'Eau, 15 avenue du Charmois, 54500 Vandoeuvre-lès-Nancy, France.
authors.forename: A
authors.initials: A
authors.lastname: Conrad
authors.forename: A
authors.initials: A
authors.lastname: Cadoret
authors.forename: P
authors.initials: P
authors.lastname: Corteel
authors.forename: P
authors.initials: P
authors.lastname: Leroy
authors.forename: J-C
authors.initials: JC
authors.lastname: Block
mesh_terms: D000327:Adsorption; D000418:Albumins / Q000032:analysis*; D017738:Alkanesulfonic Acids / Q000032:analysis*; D002364:Caseins / Q000032:analysis*; D002851:Chromatography, High Pressure Liquid; D012722:Sewage / Q000737:chemistry*; D014874:Water Pollutants, Chemical / Q000032:analysis*; D018508:Water Purification / Q000379:methods*
chemical_list: D000418:Albumins; D017738:Alkanesulfonic Acids; D002364:Caseins; D012722:Sewage; D014874:Water Pollutants, Chemical; C030641:alkylbenzyl sulfonic acid; C031460:azoalbumin; C026018:azocasein