TY - JOUR
T1 - Removal of Escherichia coli and total bacteria from water by granulated micelle-clay complexes
T2 - Filter regeneration and modeling of filtration kinetics
AU - Kalfa, Ayelet
AU - Rakovitsky, Nadya
AU - Tavassi, Mordechay
AU - Ryskin, Mark
AU - Ben-Ari, Julius
AU - Etkin, Hanoch
AU - Shuali, Uri
AU - Nir, Shlomo
N1 - Publisher Copyright:
© 2017 Elsevier B.V.
PY - 2017/10
Y1 - 2017/10
N2 - Granulated micelle-clay composites (0.3 to 2 mm) formed from Na-bentonite and the organic cations Octadecyltrimethylammonium (ODTMA), or Benzyldimethylhexadecylammonium (BDMHDA) were employed to remove from water by filtration (a) Escherichia coli S-17 and (b) total bacteria count (TBC). In (a) filters included 4 g to 27 g of complex mixed with sand, and bacteria numbers were 6.4·105 to 5·106/mL. A model which considered convection, adsorption, and desorption simulated the filtration results and yielded predictions. Bacteria capture by filtration was independent of the complex used, but BDMHDA complexes were superior in reducing numbers of emerging bacteria, due to a larger biocidal, or biostatic effect of released cations. Placing a layer of activated carbon after the micelle-clay filter reduced the released cations to 1 μg/L. Regeneration was by: (i) passing a solution of 0.1% NaOCl, or 0.01 M of HCl, or (ii) heating in a furnace at 105 °C for 2.5 h. Capacities for removal of bacteria after first and second regenerations by (i) were 86% and 57% of those with fresh granules, respectively. It is suggested that the technology can provide a safe and economical treatment for drinking water contaminated by pathogenic bacteria. In (b) the capacity of filters was smaller than in (a), but the technology enables to avoid using UV lamps in domestic filters.
AB - Granulated micelle-clay composites (0.3 to 2 mm) formed from Na-bentonite and the organic cations Octadecyltrimethylammonium (ODTMA), or Benzyldimethylhexadecylammonium (BDMHDA) were employed to remove from water by filtration (a) Escherichia coli S-17 and (b) total bacteria count (TBC). In (a) filters included 4 g to 27 g of complex mixed with sand, and bacteria numbers were 6.4·105 to 5·106/mL. A model which considered convection, adsorption, and desorption simulated the filtration results and yielded predictions. Bacteria capture by filtration was independent of the complex used, but BDMHDA complexes were superior in reducing numbers of emerging bacteria, due to a larger biocidal, or biostatic effect of released cations. Placing a layer of activated carbon after the micelle-clay filter reduced the released cations to 1 μg/L. Regeneration was by: (i) passing a solution of 0.1% NaOCl, or 0.01 M of HCl, or (ii) heating in a furnace at 105 °C for 2.5 h. Capacities for removal of bacteria after first and second regenerations by (i) were 86% and 57% of those with fresh granules, respectively. It is suggested that the technology can provide a safe and economical treatment for drinking water contaminated by pathogenic bacteria. In (b) the capacity of filters was smaller than in (a), but the technology enables to avoid using UV lamps in domestic filters.
KW - Bacterial removal
KW - Cation release
KW - Filtration modeling
KW - Granulated micelle-clay
UR - http://www.scopus.com/inward/record.url?scp=85024127456&partnerID=8YFLogxK
U2 - 10.1016/j.clay.2017.06.023
DO - 10.1016/j.clay.2017.06.023
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AN - SCOPUS:85024127456
SN - 0169-1317
VL - 147
SP - 63
EP - 68
JO - Applied Clay Science
JF - Applied Clay Science
ER -