Ceramic-supported graphene oxide membrane bioreactor for the anaerobic decolorization of azo dyes

Identifier:  imarina:9242333

Handle: https://hdl.handle.net/20.500.11797/imarina9242333

Authors:  Amin, MSA; Stüber, F; Giralt, J; Fortuny, A; Fabregat, A; Font, J

Abstract:
A continuous compact membrane bioreactor consisted of ceramic-supported graphene oxide membrane (CSGoM) was implemented for the first time for anaerobic biodecolorization of monoazo Acid Orange 7 (AO7), diazo Reactive Black 5 (RB5), and triazo Direct Blue 71 (DB71) solutions, showing excellent decolorization potential. The membrane was prepared by vacuum filtration of various graphene oxide solutions using a UF ceramic flat element. The decolorization efficiency of the CSGoM bioreactor, made from 1 mg·mL?1 of GO solution (B-CSGoM-1), was investigated for several structurally distinct azo dyes, initial feed concentrations, and permeate fluxes. Maximum color removal was achieved under low feed concentration (50 mg·L?1) and permeate flux (0.05 L·m?2·h?1), reaching 99% for AO7, 96% RB5, and 92% for DB71. At this low permeate flux, the biodecolorization was stable for all azo dye solutions irrespective of the feed concentration. In a subsequent experiment under higher feed concentration and permeate flux (100 mg·L?1 and 0.10 L·m?2·h?1), the decolorization slightly fell to 93%, 85%, and 81% for monoazo, diazo, and triazo solutions, respectively. The existence of anaerobic bacteria (Geobacter and Pseudomonas guangdongensis) in the B-CSGoM-1 biofilm confirms that they could perform efficient biodegradation of azo dye molecules in association with the graphene oxide membrane. © 2021 The Authors