title: Adhesion of bacteria to pyrophyllite clay in aqueous solution.
abstract: The aim of this study was to investigate the adhesion of bacteria (Escherichia coli) to pyrophyllite clay using batch and flow-through column experiments. Batch results demonstrated that pyrophyllite was effective in removing bacteria (94.5 +/- 2.0%) from aqueous solution (1 mM NaCl solution; pyrophyllite dose of 1 g/ml). At solution pH 7.1, negatively-charged bacteria could be removed due to their adhesion to positively-charged surfaces of pyrophyllite (point of zero charge = 9.2). Column results showed that pyrophyllite (per cent removal of 94.1 +/- 2.3%) was far more effective in bacterial adhesion than quartz sand (53.6 +/- 5.3%) under the given experimental conditions (flow rate of 0.3 ml/min; solution of 1 mM NaCl + 0.1 mM NaHCO3). Bacterial removal in pyrophyllite columns increased from 90 to 100% with decreasing flow rate from 0.6 to 0.15 ml/min due to increasing contact time between bacteria and filter materials. In addition, bacterial removal remained relatively constant at 94-97% even though NaHCO3 concentration increased from 0.1 to 10 mM (flow rate of 0.3 ml/min). This could be related to the fact that pyrophyllite remained positively-charged even though the solution conditions changed. This study demonstrates that pyrophyllite could be used as adsorptive filter materials in the removal of bacteria.
authors.affiliation: Environmental Biocolloid Engineering Laboratory, Seoul National University, Seoul, Korea.
authors.forename: Jin-Kyu
authors.initials: JK
authors.lastname: Kang
authors.forename: Chang-Gu
authors.initials: CG
authors.lastname: Lee
authors.forename: Jeong-Ann
authors.initials: JA
authors.lastname: Park
authors.forename: Song-Bae
authors.initials: SB
authors.lastname: Kim
authors.forename: Nag-Choul
authors.initials: NC
authors.lastname: Choi
authors.forename: Seong-Jik
authors.initials: SJ
authors.lastname: Park
mesh_terms: D000327:Adsorption; D000538:Aluminum Silicates / Q000737:chemistry*; D001422:Bacterial Adhesion / Q000502:physiology*; D000077215:Clay; D004926:Escherichia coli / Q000302:isolation & purification* / Q000502:physiology*; D014462:Ultrafiltration / Q000379:methods*; D014867:Water / Q000737:chemistry*; D014871:Water Microbiology; D018508:Water Purification / Q000379:methods
chemical_list: D000538:Aluminum Silicates; D014867:Water; C049037:aluminosilicate; D000077215:Clay