title: Fate of cerium dioxide (CeO2) nanoparticles in municipal wastewater during activated sludge treatment.
abstract: This study investigated the fate of nano-CeO(2) during municipal wastewater treatment using a laboratory-scale activated sludge (A/S) system fed with primarily-treated municipal wastewater and nano-CeO(2) (55.0 mg Ce/L). Nano-CeO(2) was highly removed during A/S treatment (96.6% total Ce). Extensive removal of CeO(2) <200 nm was also attained and the concentration escaping treatment was only 0.11 mg Ce/L. Elimination occurred mainly by aggregation and settling of CeO(2) particles, promoted by circumneutral pH values and by nanoparticle interactions with organic and/or inorganic wastewater constituents. Biosorption also contributed to CeO(2) removal as shown by sludge analysis and batch adsorption studies. Batch bioassays demonstrated that nano-CeO(2) only exerted inhibition of O(2) uptake by A/S at concentrations exceeding those in the bioreactor feed (50% inhibition at 950 mg CeO(2)/L). These findings indicate that A/S treatment is expected to provide extensive removal of nano-CeO(2) in municipal wastewaters.
authors.affiliation: Department of Chemical and Environmental Engineering, University of Arizona, P.O. Box 21011, Tucson, AZ 85721, USA.
authors.forename: Francisco
authors.initials: F
authors.lastname: Gómez-Rivera
authors.forename: James A
authors.initials: JA
authors.lastname: Field
authors.forename: Dustin
authors.initials: D
authors.lastname: Brown
authors.forename: Reyes
authors.initials: R
authors.lastname: Sierra-Alvarez
mesh_terms: D000327:Adsorption; D002563:Cerium / Q000737:chemistry*; D006863:Hydrogen-Ion Concentration; D053758:Nanoparticles / Q000737:chemistry*; D010100:Oxygen / Q000378:metabolism; D010316:Particle Size; D012722:Sewage / Q000737:chemistry* / Q000382:microbiology; D013057:Spectrum Analysis; D014865:Waste Disposal, Fluid / Q000379:methods*; D014874:Water Pollutants, Chemical / Q000737:chemistry*; D018508:Water Purification / Q000379:methods*
chemical_list: D012722:Sewage; D014874:Water Pollutants, Chemical; D002563:Cerium; C030583:ceric oxide; D010100:Oxygen