title: Effects of CeO2nanoparticles on sludge aggregation and the role of extracellular polymeric substances - Explanation based on extended DLVO.
abstract: The extended DLVO (XDLVO) theory was applied to elucidate the potential effects of CeO2nanoparticles (CeO2NPs) on sludge aggregation and the role of extracellular polymeric substances (EPS). In this study, seven different concentrations of CeO2NPs were added to activated sludge cultured in sequencing batch reactors (SBRs) and compared with a control test that received no CeO2NPs. After exposure to 50mg/L CeO2NPs, a negligible change (p>0.1) occurred in the sludge volume index (SVI), whereas the flocculability and aggregation of the sludge decreased by 18.8% and 11.2%, respectively, resulting in a high effluent turbidity. The XDLVO theory demonstrated that the adverse effects of the CeO2NPs on sludge aggregation were due to an enhanced barrier energy. Compared to the van der Waals energies (WA) and the electric double layer (WR), the acid-base interaction (WAB) markedly changed for the various concentrations of CeO2NPs. The EPS played a decisive role in the sludge surface characteristics, as the removal of EPS equals to the negative effects induced by 5-10mg/L CeO2NPs on the sludge flocculability and aggregation. The presence of CeO2NPs induced negative contributions to the tight boundary EPS (TB-EPS) and core bacteria while positive contributions to the total interaction energy of the loose boundary EPS (LB-EPS).
authors.affiliation: Key Laboratory of Integrated Regulation and Resources Development on Shallow Lakes, Ministry of Education, Hohai University, Nanjing 210098, People's Republic of China; College of Environment, Hohai University, Nanjing 210098, People's Republic of China.
authors.forename: Guoxiang
authors.initials: G
authors.lastname: You
authors.affiliation: Key Laboratory of Integrated Regulation and Resources Development on Shallow Lakes, Ministry of Education, Hohai University, Nanjing 210098, People's Republic of China; College of Environment, Hohai University, Nanjing 210098, People's Republic of China. Electronic address: hhuhjyhj@126.com.
authors.forename: Jun
authors.initials: J
authors.lastname: Hou
authors.affiliation: Key Laboratory of Integrated Regulation and Resources Development on Shallow Lakes, Ministry of Education, Hohai University, Nanjing 210098, People's Republic of China; College of Environment, Hohai University, Nanjing 210098, People's Republic of China. Electronic address: pfwang2005@hhu.edu.cn.
authors.forename: Peifang
authors.initials: P
authors.lastname: Wang
authors.affiliation: Key Laboratory of Integrated Regulation and Resources Development on Shallow Lakes, Ministry of Education, Hohai University, Nanjing 210098, People's Republic of China; College of Environment, Hohai University, Nanjing 210098, People's Republic of China.
authors.forename: Yi
authors.initials: Y
authors.lastname: Xu
authors.affiliation: Key Laboratory of Integrated Regulation and Resources Development on Shallow Lakes, Ministry of Education, Hohai University, Nanjing 210098, People's Republic of China; College of Environment, Hohai University, Nanjing 210098, People's Republic of China.
authors.forename: Chao
authors.initials: C
authors.lastname: Wang
authors.affiliation: Key Laboratory of Integrated Regulation and Resources Development on Shallow Lakes, Ministry of Education, Hohai University, Nanjing 210098, People's Republic of China; College of Environment, Hohai University, Nanjing 210098, People's Republic of China.
authors.forename: Lingzhan
authors.initials: L
authors.lastname: Miao
authors.affiliation: Key Laboratory of Integrated Regulation and Resources Development on Shallow Lakes, Ministry of Education, Hohai University, Nanjing 210098, People's Republic of China; College of Environment, Hohai University, Nanjing 210098, People's Republic of China.
authors.forename: Bowen
authors.initials: B
authors.lastname: Lv
authors.affiliation: Key Laboratory of Integrated Regulation and Resources Development on Shallow Lakes, Ministry of Education, Hohai University, Nanjing 210098, People's Republic of China; College of Environment, Hohai University, Nanjing 210098, People's Republic of China.
authors.forename: Yangyang
authors.initials: Y
authors.lastname: Yang
authors.affiliation: Key Laboratory of Integrated Regulation and Resources Development on Shallow Lakes, Ministry of Education, Hohai University, Nanjing 210098, People's Republic of China; College of Environment, Hohai University, Nanjing 210098, People's Republic of China.
authors.forename: Hao
authors.initials: H
authors.lastname: Luo
mesh_terms: D001422:Bacterial Adhesion; D019149:Bioreactors / Q000382:microbiology; D002563:Cerium / Q000737:chemistry*; D005109:Extracellular Matrix / Q000737:chemistry*; D005427:Flocculation; D008962:Models, Theoretical; D053758:Nanoparticles / Q000737:chemistry*; D012722:Sewage / Q000737:chemistry / Q000382:microbiology*; D018508:Water Purification / Q000379:methods*
chemical_list: D012722:Sewage; D002563:Cerium; C030583:ceric oxide
keywords: CeO(2) nanoparticle; Extended DLVO theory; Extracellular polymeric substances; Sludge aggregation; Total interaction energy