Effect of dye structure and redox mediators on anaerobic azo and anthraquinone dye reduction

Costa, Mayara Carantino; Mota, Francisco Suetônio Bastos; Santos, André Bezerra dos; Mendonça, Glaydson L.F.; Nascimento, Ronaldo F.

doi:10.1590/s0100-40422012000300008

Cited by 29 publications

(9 citation statements)

References 19 publications

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“…3,4 Certain characteristics of dyes such as toxicity, resistance to degradation and photodegradation rates are believed to be dependent on the chemical structure of each dye. 4,5 For example, Giwa et al, 6 investigated the photodegradation of Reactive Yellow 81 and Reactive Violet 1 in aqueous solution with TiO 2 -P25 (Degussa) and observed that structural variation between the dyes molecules may have influenced their degradation rates. With regards to aromatic compounds, the number, position and the electronic nature of the substituents determine the efficiency of the photocatalytic degradation process.…”

Section: Introductionmentioning

confidence: 99%

Comparative photocatalytic degradation of monoazo and diazo dyes under simulated visible light using Fe3+/C/S doped-TiO2 nanoparticles

Anku

Oppong²,

Shukla³

et al. 2016

ACSi

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This research work delved into the photocatalytic degradation of monoazo dye (methyl orange) and diazo dye (congo red) in aqueous solution using Fe 3+ /C/S-doped TiO 2 nanocomposites. The nanocomposites were synthesised through sol-gel method and characterized using XRD, FTIR, SEM, TEM, EDX, BET and UV-Vis. Photocatalytic degradation of the dyes was monitored under simulated visible light using pristine TiO 2 , C/S/doped-TiO 2 and Fe 3+ /C/S doped-TiO 2 with varying concentrations of Fe 3+ . The influence of catalyst doping, solution pH, and light intensity were also examined. Doping TiO 2 with Fe 3+ /C/S caused reduction in its band gap value with the resultant improvement in its visible light activity. The photocatalytic efficiency of the catalysts is given as follows: TiO 2 < C/S/TiO 2 < Fe 3+ /C/S-TiO 2 with Fe 3+ /C/S-TiO 2 (0.3% Fe 3+ ) as the best performing photocatalyst. The monoazo dye experienced higher degradation efficiency than the diazo dye. Degradation of the azo dyes was observed to decrease with increasing pH from 2 to 12. Increased visible light intensity enhanced the photodegradation efficiency of the dye. Dye decolourization was observed to be faster than its mineralization.

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Section: Introductionmentioning

confidence: 99%

Comparative photocatalytic degradation of monoazo and diazo dyes under simulated visible light using Fe3+/C/S doped-TiO2 nanoparticles

Anku

Oppong²,

Shukla³

et al. 2016

ACSi

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“…This is in line with recent reports of anoxic fungal degradation in terrestrial ( Ivarsson et al, 2016 ; Drake and Ivarsson, 2018 ) and marine environments ( Barone et al, 2019 ; Zain UI Arifeen et al, 2019 ). CR was the substrate that was most decolorized by fungi under anoxia; this is not surprising, as CR is the most soluble and least recalcitrant of all substrates tested ( Costa et al, 2012 ). Under oxic conditions the color change of CR media varied between species, from a loss in color to the media becoming dark (red, gray, or black) and, in some cases, later becoming losing color again after initially darkening.…”

Section: Discussionmentioning

confidence: 89%

Oxic and Anoxic Organic Polymer Degradation Potential of Endophytic Fungi From the Marine Macroalga, Ecklonia radiata

et al. 2021

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Cellulose and chitin are the most abundant polymeric, organic carbon source globally. Thus, microbes degrading these polymers significantly influence global carbon cycling and greenhouse gas production. Fungi are recognized as important for cellulose decomposition in terrestrial environments, but are far less studied in marine environments, where bacterial organic matter degradation pathways tend to receive more attention. In this study, we investigated the potential of fungi to degrade kelp detritus, which is a major source of cellulose in marine systems. Given that kelp detritus can be transported considerable distances in the marine environment, we were specifically interested in the capability of endophytic fungi, which are transported with detritus, to ultimately contribute to kelp detritus degradation. We isolated 10 species and two strains of endophytic fungi from the kelp Ecklonia radiata. We then used a dye decolorization assay to assess their ability to degrade organic polymers (lignin, cellulose, and hemicellulose) under both oxic and anoxic conditions and compared their degradation ability with common terrestrial fungi. Under oxic conditions, there was evidence that Ascomycota isolates produced cellulose-degrading extracellular enzymes (associated with manganese peroxidase and sulfur-containing lignin peroxidase), while Mucoromycota isolates appeared to produce both lignin and cellulose-degrading extracellular enzymes, and all Basidiomycota isolates produced lignin-degrading enzymes (associated with laccase and lignin peroxidase). Under anoxic conditions, only three kelp endophytes degraded cellulose. We concluded that kelp fungal endophytes can contribute to cellulose degradation in both oxic and anoxic environments. Thus, endophytic kelp fungi may play a significant role in marine carbon cycling via polymeric organic matter degradation.

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“…Lawsone, RF, and AQDS were effective in stimulating on Te IV reduction rates; however, RF was the most effective RM for Te IV . RF has previously been successfully used to catalyze the reduction of several azo dyes, , chloroform, and ferric iron (Fe III ) . Likewse AQDS was also previously shown to be effective in shuttling electrons for azo dye reduction and Fe III reduction .…”

Section: Results and Discussionmentioning

confidence: 99%

Recovery of Elemental Tellurium Nanoparticles by the Reduction of Tellurium Oxyanions in a Methanogenic Microbial Consortium

Ramos-Ruiz

Field

Wilkening

et al. 2016

Environ. Sci. Technol.

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This research focuses on the microbial recovery of elemental tellurium (Te0) from aqueous streams containing soluble tellurium oxyanions, tellurate (TeVI) and tellurite (TeIV). An anaerobic mixed microbial culture occurring in methanogenic granular sludge was able to biocatalyze the reduction of both Te oxyanions to produce Te0 nanoparticles (NPs) in sulfur-free medium. TeIV reduction was 7-fold faster than that of TeVI, such that TeIV did not accumulate to a great extent during TeVI reduction. Endogenous substrates in the granular sludge provided the electron equivalents required to reduce Te oxyanions; however, the reduction rates were modestly increased with an exogenous electron donor such as H2. The effect of four redox mediators (anthraquinone-2,6-disulfonate, hydroxocobalamin, riboflavin, and lawsone) was also tested. Riboflavin increased the rate of TeIV reduction by 11-fold and also enhanced the fraction Te recovered as extracellular Te0 NPs from 21% to 64%. Lawsone increased the rate of TeVI reduction by 5-fold and the fraction of Te recovered as extracellular material increased from 49% to 83%. The redox mediators and electron donors also impacted the morphologies and localization of Te0 NPs, suggesting that NP production can be tailored for a particular application.

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Effect of dye structure and redox mediators on anaerobic azo and anthraquinone dye reduction

Cited by 29 publications

References 19 publications

Comparative photocatalytic degradation of monoazo and diazo dyes under simulated visible light using Fe3+/C/S doped-TiO2 nanoparticles

Comparative photocatalytic degradation of monoazo and diazo dyes under simulated visible light using Fe3+/C/S doped-TiO2 nanoparticles

Oxic and Anoxic Organic Polymer Degradation Potential of Endophytic Fungi From the Marine Macroalga, Ecklonia radiata

Recovery of Elemental Tellurium Nanoparticles by the Reduction of Tellurium Oxyanions in a Methanogenic Microbial Consortium

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