Bacterial attachment to iron-impregnated granular activated carbon.
Bacterial attachment to iron-impregnated granular activated carbon (Fe-GAC) was investigated in this study using Enterococcus faecalis ATCC 10100 and charcoal-based GAC. Two sets of column experiments were performed under different ionic strengths and pH conditions. Breakthrough curves of bacteria were obtained by monitoring effluent. Mass recoveries and attachment rate coefficients were quantified from these curves. In addition, characteristics of Fe-GAC were analyzed using field emission scanning electron microscopy (FESEM) and X-ray spectrometry (EDS). Results show that Fe-GAC was characterized by mosaic-like deposition layers of iron oxides with about 2 microm in thickness. Color mapping with FESEM visualized the spatial distribution of carbon (yellow-green) and iron (red) on Fe-GAC. EDS indicates that iron was distinctly found from Fe-GAC at three peak positions. Results also reveal that bacterial attachment to Fe-GAC was affected by ionic strength and pH. Bacterial mass recoveries decreased from 62.9 to 41.7% with increasing ionic strength from 1 to 50 mM. This indicates that bacterial attachment to the surfaces of Fe-GAC was enhanced with increasing ionic strength. With increasing pH from 6.46 to 9.19, mass recoveries increased from 50.5 to 84.2%, indicating that bacterial attachment to Fe-GAC was reduced with increasing pH. This study demonstrates that iron oxides offer favorable attachment sites for bacteria on the surfaces of Fe-GAC and further improves the knowledge of bacterial removal in Fe-GAC.
Kim
Hyon-Chong
HC
Environmental Biocolloid Engineering Laboratory/Research Institute for Agriculture and Life Sciences, Seoul National University, Seoul 151-921, Republic of Korea.
Park
Seong-Jik
SJ
Lee
Chang-Gu
CG
Kim
Song-Bae
SB
Kim
Ki-Woo
KW
D001422:Bacterial Adhesion; D018533:Biomass; D002606:Charcoal / Q000378:metabolism*; D013293:Enterococcus faecalis / Q000166:cytology* / Q000648:ultrastructure; D006863:Hydrogen-Ion Concentration; D007501:Iron / Q000737:chemistry*; D008855:Microscopy, Electron, Scanning; D009994:Osmolar Concentration; D012996:Solutions
D012996:Solutions; D002606:Charcoal; D007501:Iron