title: Graphene oxide as electron shuttle for increased redox conversion of contaminants under methanogenic and sulfate-reducing conditions.
abstract: Graphene oxide (GO) is reported for the first time as electron shuttle to increase the redox conversion of the azo compound, reactive red 2 (RR2, 0.5mM), and the nitroaromatic, 3-chloronitrobenzene (3CNB, 0.5mM). GO (5mgL(-1)) increased 10-fold and 7.6-fold the reduction rate of RR2 and 3CNB, respectively, in abiotic incubations with sulfide (2.6mM) as electron donor. GO also increased by 2-fold and 3.6-fold, the microbial reduction rate of RR2 by anaerobic sludge under methanogenic and sulfate-reducing conditions, respectively. Deep characterization of GO showed that it has a proper size distribution (predominantly between 450 and 700nm) and redox potential (+50.8mV) to promote the reduction of RR2 and 3CNB. Further analysis revealed that biogenic sulfide plays a major role on the GO-mediated reduction of RR2. GO is proposed as an electron shuttle to accelerate the redox conversion of recalcitrant pollutants, such as nitro-benzenes and azo dyes.
authors.affiliation: División de Ciencias Ambientales, Instituto Potosino de Investigación Científica y Tecnológica (IPICyT), Camino a la Presa San José 2055, Col. Lomas 4ª, Sección, San Luis Potosí, SLP 78216, Mexico.
authors.forename: Alejandra
authors.initials: A
authors.lastname: Colunga
authors.affiliation: División de Ciencias Ambientales, Instituto Potosino de Investigación Científica y Tecnológica (IPICyT), Camino a la Presa San José 2055, Col. Lomas 4ª, Sección, San Luis Potosí, SLP 78216, Mexico.
authors.forename: J Rene
authors.initials: JR
authors.lastname: Rangel-Mendez
authors.affiliation: División de Ciencias Ambientales, Instituto Potosino de Investigación Científica y Tecnológica (IPICyT), Camino a la Presa San José 2055, Col. Lomas 4ª, Sección, San Luis Potosí, SLP 78216, Mexico.
authors.forename: Lourdes B
authors.initials: LB
authors.lastname: Celis
authors.affiliation: División de Ciencias Ambientales, Instituto Potosino de Investigación Científica y Tecnológica (IPICyT), Camino a la Presa San José 2055, Col. Lomas 4ª, Sección, San Luis Potosí, SLP 78216, Mexico. Electronic address: fjcervantes@ipicyt.edu.mx.
authors.forename: Francisco J
authors.initials: FJ
authors.lastname: Cervantes
mesh_terms: D000693:Anaerobiosis; D001419:Bacteria / Q000378:metabolism; D001673:Biodegradation, Environmental; D004583:Electrons; D004785:Environmental Pollutants / Q000378:metabolism*; D006108:Graphite / Q000737:chemistry*; D007700:Kinetics; D008697:Methane / Q000378:metabolism*; D009282:Naphthalenesulfonates / Q000378:metabolism; D009578:Nitrobenzenes / Q000378:metabolism; D010084:Oxidation-Reduction; D010316:Particle Size; D012722:Sewage / Q000382:microbiology; D013431:Sulfates / Q000378:metabolism*; D013440:Sulfides / Q000378:metabolism; D014227:Triazines / Q000378:metabolism
chemical_list: D004785:Environmental Pollutants; D009282:Naphthalenesulfonates; D009578:Nitrobenzenes; D012722:Sewage; D013431:Sulfates; D013440:Sulfides; D014227:Triazines; C098610:reactive red 2; D006108:Graphite; C032785:2-chloronitrobenzene; D008697:Methane
keywords: Anaerobic sludge; Graphene oxide; Methanogenesis; Redox mediator; Sulfate reduction