title: DLVO, hydrophobic, capillary and hydrodynamic forces acting on bacteria at solid-air-water interfaces: Their relative impact on bacteria deposition mechanisms in unsaturated porous media.
abstract: Experimental and modeling studies were performed to investigate bacteria deposition behavior in unsaturated porous media. The coupled effect of different forces, acting on bacteria at solid-air-water interfaces and their relative importance on bacteria deposition mechanisms was explored by calculating Derjaguin-Landau-Verwey-Overbeek (DLVO) and non-DLVO interactions such as hydrophobic, capillary and hydrodynamic forces. Negatively charged non-motile bacteria and quartz sands were used in packed column experiments. The breakthrough curves and retention profiles of bacteria were simulated using the modified Mobile-IMmobile (MIM) model, to identify physico-chemical attachment or physical straining mechanisms involved in bacteria retention. These results indicated that both mechanisms might occur in both sand. However, the attachment was found to be a reversible process, because attachment coefficients were similar to those of detachment. DLVO calculations supported these results: the primary minimum did not exist, suggesting no permanent retention of bacteria to solid-water and air-water interfaces. Calculated hydrodynamic and resisting torques predicted that bacteria detachment in the secondary minimum might occur. The capillary potential energy was greater than DLVO, hydrophobic and hydrodynamic potential energies, suggesting that film straining by capillary forces might largely govern bacteria deposition under unsaturated conditions.
authors.affiliation: Sorbonne Universités, Université de Technologie de Compiègne, UTC/ESCOM, EA 4297 TIMR, Centre de Recherche Royallieu, CS 60 319, 60 203 Compiègne Cedex, France.
authors.forename: Hongjuan
authors.initials: H
authors.lastname: Bai
authors.affiliation: Sorbonne Universités, Université de Technologie de Compiègne, UTC/ESCOM, EA 4297 TIMR, Centre de Recherche Royallieu, CS 60 319, 60 203 Compiègne Cedex, France.
authors.forename: Nelly
authors.initials: N
authors.lastname: Cochet
authors.affiliation: Sorbonne Universités, Université de Technologie de Compiègne, UTC/ESCOM, EA 4297 TIMR, Centre de Recherche Royallieu, CS 60 319, 60 203 Compiègne Cedex, France.
authors.forename: André
authors.initials: A
authors.lastname: Pauss
authors.affiliation: Sorbonne Universités, Université de Technologie de Compiègne, UTC/ESCOM, EA 4297 TIMR, Centre de Recherche Royallieu, CS 60 319, 60 203 Compiègne Cedex, France. Electronic address: edvina.lamy@utc.fr.
authors.forename: Edvina
authors.initials: E
authors.lastname: Lamy
mesh_terms: D000388:Air; D001422:Bacterial Adhesion; D001692:Biological Transport; D003198:Computer Simulation; D003470:Culture Media; D057446:Hydrodynamics; D057927:Hydrophobic and Hydrophilic Interactions; D007700:Kinetics; D007709:Klebsiella / Q000502:physiology*; D015233:Models, Statistical; D016062:Porosity; D012240:Rhodococcus / Q000502:physiology*; D013816:Thermodynamics; D019415:Torque; D014867:Water / Q000737:chemistry
chemical_list: D003470:Culture Media; D014867:Water
keywords: Bacteria deposition; Capillary forces; DLVO; Hydrodynamic forces; Hydrophobic forces; Unsaturated conditions