title: Flocculation of Escherichia coli using a quaternary ammonium salt grafted carboxymethyl chitosan flocculant.
abstract: Only few studies are available on bacteria removal efficiencies and antibacterial properties of flocculants, which is one of the important requirements in water treatment work. Escherichia coli (E. coli) was selected as an example of a Gram-negative bacteria for testing the flocculating properties of a quaternary ammonium salt grafted chitosan (carboxymethyl chitosan-graft-poly[(2-methacryloyloxyethyl) trimethylammonium chloride] copolymer; i.e., CMC-g-PDMC). The effect of various flocculation parameters, including flocculant dosage, initial bacterial density, nutrient medium content, and pH were successively investigated. The experimental results indicated that, besides flocculation effects, CMC-g-PDMC also exhibited a bactericidal effect (not requiring additional treatment facilities). Moreover, the flocculation mechanisms were investigated via zeta potential measurements, floc observation, and three-dimensional excitation-emission matrix spectra analysis. Apart from its flocculating and settling effect, this chitosan-based material has bactericidal action through the breaking of bacterial cell walls by grafted quaternary ammonium salt.
authors.affiliation: State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, School of Chemistry & Chemical Engineering, Nanjing University , Nanjing 210093, P. R. China.
authors.forename: Zhen
authors.initials: Z
authors.lastname: Yang
authors.forename: Jean-Regis
authors.initials: JR
authors.lastname: Degorce-Dumas
authors.forename: Hu
authors.initials: H
authors.lastname: Yang
authors.forename: Eric
authors.initials: E
authors.lastname: Guibal
authors.forename: Aimin
authors.initials: A
authors.lastname: Li
authors.forename: Rongshi
authors.initials: R
authors.lastname: Cheng
mesh_terms: D048271:Chitosan / Q000031:analogs & derivatives* / Q000494:pharmacology; D003470:Culture Media / Q000737:chemistry; D004777:Environment; D004926:Escherichia coli / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D005427:Flocculation / Q000187:drug effects; D006863:Hydrogen-Ion Concentration; D000644:Quaternary Ammonium Compounds / Q000494:pharmacology*; D012996:Solutions; D013050:Spectrometry, Fluorescence
chemical_list: D003470:Culture Media; D000644:Quaternary Ammonium Compounds; D012996:Solutions; C514968:carboxymethyl-chitosan; D048271:Chitosan