Open AccessBiotransformation of congo red in a UASB reactor under salinity conditions using immobilized redox mediator in granular activated carbon
Author(s) -
Glenda A. Espinoza,
Verónica Almaguer-Cantú,
Refugio Bernardo García-Reyes,
Edna R. Meza,
Denisse SerranoPalacios,
Luis H. Álvarez
Publication year - 2021
Publication title -
mexican journal of biotechnology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.124
H-Index - 3
ISSN - 2448-6590
DOI - 10.29267/mxjb.2021.6.4.17
Subject(s) - biotransformation , chemistry , bioreactor , activated sludge , hydraulic retention time , activated carbon , substrate (aquarium) , anaerobic exercise , biosorption , salinity , anthraquinone , biodegradation , congo red , redox , chromatography , nuclear chemistry , wastewater , inorganic chemistry , organic chemistry , environmental engineering , adsorption , enzyme , sorption , biology , physiology , ecology , engineering , oceanography , geology
Azo dyes are susceptible to be treated by reductive biotransformation process under anaerobic conditions. The process can be accelerated by the addition of quinones and humic substances acting as redox mediators (RM). In this study, the anthraquinone-2-sulfonate (AQS) was immobilized on granular activated carbon (GAC) to evaluate the reductive biotransformation of congo red (CR) in an up-flow anaerobic sludge blanket reactor (UASB). The syudy was divided in five stages, where the reactors with immobilized RM and without RM were operated under different salinity levels (1% and 3%) and hydraulic retention times (HRT = 5 and 10 h). The reactor with immobilized RM (GAC-AQS) achieved a decolorization efficiency of 96.1% and substrate consumption of 98.8% with a HRT = 15 h and 1% of salinity. Nonetheless, with a salinity of 3% and the same HRT, the efficiency was similar (95.6%). The reactor provided with unmodified GAC achieved values below those observed in the reactor GAC-AQS, with decolorization efficiencies of 90.8% and 75.8%, and substrate consumption of 97.1% and 88.4%, for the stages IV and V, respectively. The microbial consortium sued was able to promote the biotransformation of azo dye and no inhibitory effects were identified.