title: Bovine serum albumin adsorption to iron-oxide coated sands can change microsphere deposition mechanisms.
abstract: Particulate colloids often occur together with proteins in sewage-impacted water. Using Bovine Serum Albumin (BSA) as a surrogate for protein in sewage, column experiments investigating the capacity of iron-oxide coated sands to remove latex microspheres from water revealed that microsphere attenuation mechanisms depended on antecedent BSA coverage. Dual pulse experiment (DPE) results suggested that where all BSA was adsorbed, subsequent multiple pore volume microsphere breakthrough curves reflected progressively reduced colloid deposition rates with increasing adsorbed BSA content. Modeling colloid responses suggested adsorption of 1 μg BSA generated the same response as blockage by between 7.1 × 10(8) and 2.3 × 10(9) deposited microspheres. By contrast, microsphere responses in DPEs where BSA coverage of the deposition sites approached/reached saturation revealed the coated sand maintained a finite capacity to attenuate microspheres, even when incapable of further BSA adsorption. Subsequent microsphere breakthrough curves demonstrated the matrix's colloid attenuation capacity progressively increased with continued microsphere deposition. Experimental findings suggested BSA adsorption on the sand surface approaching/reaching saturation generated attractive deposition sites for colloids, which became progressively more attractive with further colloid deposition (filter ripening). Results demonstrate that adsorption of a single type of protein may either enhance or inhibit colloid mobility in saturated porous media.
authors.affiliation: School of Planning, Architecture & Civil Engineering, Queen's University Belfast, David Keir Building, Stranmillis Road, Belfast BT9 5AG N Ireland, UK. r.flynn@qub.ac.uk
authors.forename: Raymond M
authors.initials: RM
authors.lastname: Flynn
authors.forename: Xinyao
authors.initials: X
authors.lastname: Yang
authors.forename: Thilo
authors.initials: T
authors.lastname: Hofmann
authors.forename: Frank
authors.initials: F
authors.lastname: von der Kammer
mesh_terms: D000327:Adsorption; D000818:Animals; D002417:Cattle; D003198:Computer Simulation; D005290:Ferric Compounds / Q000737:chemistry*; D008863:Microspheres; D008956:Models, Chemical; D010316:Particle Size; D016062:Porosity; D012710:Serum Albumin, Bovine / Q000737:chemistry*; D012822:Silicon Dioxide / Q000737:chemistry*; D055672:Static Electricity
chemical_list: D005290:Ferric Compounds; C000499:ferric oxide; D012710:Serum Albumin, Bovine; D012822:Silicon Dioxide