title: Immobilization of metal-humic acid complexes in anaerobic granular sludge for their application as solid-phase redox mediators in the biotransformation of iopromide in UASB reactors.
abstract: Metal-humic acid complexes were synthesized and immobilized by a granulation process in anaerobic sludge for their application as solid-phase redox mediators (RM) in the biotransformation of iopromide. Characterization of Ca- and Fe-humic acid complexes revealed electron accepting capacities of 0.472 and 0.556milli-equivalentsg(-1), respectively. Once immobilized, metal-humic acid complexes significantly increased the biotransformation of iopromide in upflow anaerobic sludge blanket (UASB) reactors. Control UASB reactor (without humic material) achieved 31.6% of iopromide removal, while 80% was removed in UASB reactors supplied with each metal-humic acid complex. Further analyses indicated multiple transformation reactions taking place in iopromide including deiodination, N-dealkylation, decarboxylation and deacetylation. This is the first successful application of immobilized RM, which does not require a supporting material to maintain the solid-phase RM in long term operation of bioreactors. The proposed redox catalyst could be suitable for enhancing the redox conversion of different recalcitrant pollutants present in industrial effluents.
authors: División de Ciencias Ambientales, Instituto Potosino de Investigación Científica y Tecnológica (IPICYT), Camino a la Presa San José 2055, Col. Lomas 4ª. Sección, C. P. 78216 San Luis Potosí, SLP, Mexico.
authors: Aracely S
authors: AS
authors: Cruz-Zavala
authors: División de Ciencias Ambientales, Instituto Potosino de Investigación Científica y Tecnológica (IPICYT), Camino a la Presa San José 2055, Col. Lomas 4ª. Sección, C. P. 78216 San Luis Potosí, SLP, Mexico.
authors: Aurora M
authors: AM
authors: Pat-Espadas
authors: División de Ciencias Ambientales, Instituto Potosino de Investigación Científica y Tecnológica (IPICYT), Camino a la Presa San José 2055, Col. Lomas 4ª. Sección, C. P. 78216 San Luis Potosí, SLP, Mexico.
authors: J Rene
authors: JR
authors: Rangel-Mendez
authors: División de Ciencias Ambientales, Instituto Potosino de Investigación Científica y Tecnológica (IPICYT), Camino a la Presa San José 2055, Col. Lomas 4ª. Sección, C. P. 78216 San Luis Potosí, SLP, Mexico.
authors: Luis F
authors: LF
authors: Chazaro-Ruiz
authors: Facultad de Ciencias Químicas, Departamento de Investigación en Alimentos (DIA-UAdeC), Universidad Autónoma de Coahuila, Saltillo 25280, Coahuila, Mexico.
authors: Juan A
authors: JA
authors: Ascacio-Valdes
authors: Facultad de Ciencias Químicas, Departamento de Investigación en Alimentos (DIA-UAdeC), Universidad Autónoma de Coahuila, Saltillo 25280, Coahuila, Mexico.
authors: Cristobal N
authors: CN
authors: Aguilar
authors: División de Ciencias Ambientales, Instituto Potosino de Investigación Científica y Tecnológica (IPICYT), Camino a la Presa San José 2055, Col. Lomas 4ª. Sección, C. P. 78216 San Luis Potosí, SLP, Mexico. Electronic address: fjcervantes@ipicyt.edu.mx.
authors: Francisco J
authors: FJ
authors: Cervantes
mesh_terms: D000693:Anaerobiosis; D057919:Biological Oxygen Demand Analysis; D019149:Bioreactors / Q000382:microbiology*; D001711:Biotransformation; D056831:Coordination Complexes / Q000737:chemistry*; D004563:Electrochemistry; D004583:Electrons; D004777:Environment; D006812:Humic Substances / Q000032:analysis*; D007472:Iohexol / Q000031:analogs & derivatives* / Q000378:metabolism; D010084:Oxidation-Reduction; D012722:Sewage / Q000382:microbiology*
chemical_list: D056831:Coordination Complexes; D006812:Humic Substances; D012722:Sewage; D007472:Iohexol; C038192:iopromide
keywords: Humus; Immobilization; Iopromide; Redox mediator; Wastewater