title: Comparison and distribution of copper oxide nanoparticles and copper ions in activated sludge reactors.
abstract: Copper oxide nanoparticles (CuO NPs) are being increasingly applied in the industry which results inevitably in the release of these materials into the hydrosphere. In this study, simulated waste-activated sludge experiments were conducted to investigate the effects of Copper Oxide NPs at concentrations of 0.1, 1, 10 and 50 mg/L and to compare it with its ionic counterpart (CuSO4). It was found that 0.1 mg/L of CuO NPs had negligible effects on Chemical Oxygen Demand (COD) and ammonia removal. However, the presence of 1, 10 and 50 mg/L of CuO NPs decreased COD removal from 78.7% to 77%, 52.1% and 39.2%, respectively (P < 0.05). The corresponding effluent ammonium (NH4-N) concentration increased from 14.9 mg/L to 18, 25.1 and 30.8 mg/L, respectively. Under equal Cu concentration, copper ions were more toxic towards microorganisms compared to CuO NPs. CuO NPs were removed effectively (72-93.2%) from wastewater due to a greater biosorption capacity of CuO NPs onto activated sludge, compared to the copper ions (55.1-83.4%). The SEM images clearly showed the accumulation and adsorption of CuO NPs onto activated sludge. The decrease in Live/dead ratio after 5 h of exposure of CuO NPs and Cu2+indicated the loss of cell viability in sludge flocs.
authors.affiliation: a Advanced Environmental Biotechnology Centre , Nanyang Environment and Water Research Institute , Singapore , Singapore.
authors.forename: Dongqing
authors.initials: D
authors.lastname: Zhang
authors.affiliation: b School of Civil Engineering & Surveying , Faculty of Health, Engineering and Sciences, University of Southern Queensland , Queensland , Australia.
authors.forename: Antoine P
authors.initials: AP
authors.lastname: Trzcinski
authors.affiliation: c Singapore Membrane Technology Centre , Nanyang Environment and Water Research Institute , Singapore , Singapore.
authors.forename: Hyun-Suk
authors.initials: HS
authors.lastname: Oh
authors.affiliation: a Advanced Environmental Biotechnology Centre , Nanyang Environment and Water Research Institute , Singapore , Singapore.
authors.forename: Evelyn
authors.initials: E
authors.lastname: Chew
authors.affiliation: a Advanced Environmental Biotechnology Centre , Nanyang Environment and Water Research Institute , Singapore , Singapore.
authors.forename: Soon Keat
authors.initials: SK
authors.lastname: Tan
authors.affiliation: a Advanced Environmental Biotechnology Centre , Nanyang Environment and Water Research Institute , Singapore , Singapore.
authors.forename: Wun Jern
authors.initials: WJ
authors.lastname: Ng
authors.affiliation: a Advanced Environmental Biotechnology Centre , Nanyang Environment and Water Research Institute , Singapore , Singapore.
authors.forename: Yu
authors.initials: Y
authors.lastname: Liu
mesh_terms: D000327:Adsorption; D057919:Biological Oxygen Demand Analysis; D003300:Copper / Q000032:analysis* / Q000737:chemistry; D007477:Ions; D053768:Metal Nanoparticles / Q000032:analysis / Q000737:chemistry; D053758:Nanoparticles / Q000032:analysis*; D012722:Sewage / Q000737:chemistry*; D062065:Wastewater / Q000737:chemistry; D014874:Water Pollutants, Chemical / Q000032:analysis* / Q000737:chemistry; D018508:Water Purification / Q000379:methods*
chemical_list: D003300:Copper; D007477:Ions; D012722:Sewage; D062065:Wastewater; D014874:Water Pollutants, Chemical; C030973:cupric oxide
keywords: CuO nanoparticles; biosorption; copper ions; waste-activated sludge