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Use of Desulfovibrio and Escherichia coli Pd‐nanocatalysts in reduction of Cr(VI) and hydrogenolytic dehalogenation of polychlorinated biphenyls and used transformer oil
Author(s) -
Macaskie Lynne E.,
Humphries Andrea C.,
Mikheenko Iryna P.,
BaxterPlant Victoria S.,
Deplanche Kevin,
Redwood Mark D.,
Bennett James A.,
Wood Joe
Publication year - 2012
Publication title -
journal of chemical technology and biotechnology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.64
H-Index - 117
eISSN - 1097-4660
pISSN - 0268-2575
DOI - 10.1002/jctb.3763
Subject(s) - nanomaterial based catalyst , catalysis , desulfovibrio , chemistry , escherichia coli , nuclear chemistry , halogenation , metal , reductive dechlorination , sulfate , organic chemistry , biochemistry , biodegradation , gene
BACKGROUND: Desulfovibrio spp. biofabricate metallic nanoparticles (e.g. ‘Bio‐Pd’) which catalyse the reduction of Cr(VI) to Cr(III) and dehalogenate polychlorinated biphenyls (PCBs). Desulfovibrio spp. are anaerobic and produce H 2 S, a potent catalyst poison, whereas Escherichia coli can be pre‐grown aerobically to high density, has well defined molecular tools, and also makes catalytically‐active ‘Bio‐Pd’. The first aim was to compare ‘Bio‐Pd’ catalysts made by Desulfovibrio spp. and E. coli using suspended and immobilized catalysts. The second aim was to evaluate the potential for Bio‐Pd‐mediated dehalogenation of PCBs in used transformer oils, which preclude recovery and re‐use. RESULTS: Catalysis via Bio‐Pd D . desulfuricans and Bio‐Pd E . coli was compared at a mass loading of Pd:biomass of 1:3 via reduction of Cr(VI) in aqueous solution (immobilized catalyst) and hydrogenolytic release of Cl − from PCBs and used transformer oil (catalyst suspensions). In both cases Bio‐Pd D . desulfuricans outperformed Bio‐Pd E . coli by ∼3.5‐fold, attributable to a ∼3.5‐fold difference in their Pd‐nanoparticle surface areas determined by magnetic measurements (Bio‐Pd D . desulfuricans ) and by chemisorption analysis (Bio‐Pd E . coli ). Small Pd particles were confirmed on D. desulfuricans and fewer, larger ones on E. coli via electron microscopy. Bio‐Pd D . desulfuricans ‐mediated chloride release from used transformer oil (5.6 ± 0.8 µg mL −1 ) was comparable with that observed using several PCB reference materials. CONCLUSIONS: At a loading of 1:3 Pd:biomass Bio‐Pd D . desulfuricans is 3.5‐fold more active than Bio‐Pd E . coli , attributable to the relative catalyst surface areas reflected in the smaller nanoparticle sizes of the former. This study also shows the potential of Bio‐Pd D . desulfuricans to remediate used transformer oil. Copyright © 2012 Society of Chemical Industry