The production of rice straw-derived biochar and its application for enhanced decolorization of azo dye as the role of redox mediator

The role of sulphate reduction on the reductive decolorization of the azo dye reactive orange 14

Water Science & Technology ◽

10.2166/wst.2006.501 ◽

2006 ◽

Vol 54 (2) ◽

pp. 171-177 ◽

Cited By ~ 15

Author(s):

F.J. Cervantes ◽

J.E. Enriquez ◽

M.R. Mendoza-Hernandez ◽

E. Razo-Flores ◽

J.A. Field

Keyword(s):

Electron Donor ◽

Azo Dye ◽

Redox Mediator ◽

Sulphate Reduction ◽

Anaerobic Sludge ◽

Biological Mechanisms ◽

Azo Reduction ◽

Reactive Orange ◽

The Impact

The aim of this study was to investigate the impact of a broad range of sulphate concentrations (0–10 g SO4−2 L−1) on the reduction of an azo dye (reactive orange 14 (RO14)) by an anaerobic sludge. An increase in the sulphate concentration generally stimulated the reduction of RO14 by sludge incubations supplemented with glucose, acetate or propionate as electron donor. Sulphate and azo dye reductions took place simultaneously in all incubations. However, there was a decrease on the rate of decolorization when sulphate was supplied at 10 g SO4−2 L−1. Abiotic incubations at different sulphide concentrations (0–2.5 g sulphide L−1) promoted very poor reduction of RO14. However, addition of riboflavin (20 μM), as a redox mediator, accelerated the reduction of RO14 up to 44-fold compared to a control lacking the catalyst. Our results indicate that sulphate-reduction may significantly contribute to the reduction of azo dyes both by biological mechanisms and by abiotic reductions implicating sulphide as an electron donor. The contribution of abiotic decolorization by sulphide, however, was only significant when a proper redox mediator was included. Our results also revealed that sulphate-reduction can out-compete with azo reduction at high sulphate concentrations leading to a poor decolorising performance when no sufficient reducing capacity is available.

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Role of Nanocrystallites of Al-Based Glasses and H2O2 in Degradation Azo Dyes

Materials ◽

10.3390/ma14010039 ◽

2020 ◽

Vol 14 (1) ◽

pp. 39

Author(s):

Qi Chen ◽

Zhicheng Yan ◽

Hao Zhang ◽

KiBuem Kim ◽

Weimin Wang

Keyword(s):

Metallic Glasses ◽

Azo Dye ◽

Amorphous Matrix ◽

Nano Scale ◽

Transmission Electron ◽

Melt Spun ◽

Degradation Ability ◽

Tem Transmission Electron Microscopy ◽

Dye Solutions

Al-based metallic glasses have a special atomic structure and should have a unique degradation ability in azo dye solutions. The Al88Ni9Y3 (Y3), Al85Ni9Y6 (Y6) and Al82Ni9Y9 (Y9) glassy ribbons are melt spun and used in degrading methyl orange (MO) azo dye solution with adding H2O2. With increasing cY, the as-spun ribbons have an increasing GFA (glass formability) and gradually decreased the degradation rate of MO solution. TEM (transmission electron microscopy) results show that the Y3 ribbon has nano-scale crystallites, which may form the channels to transport elements to the surface for degrading the MO solution. After adding H2O2, the degradation efficiency of Al-based glasses is improved and the Y6 ribbon has formed nano-scale crystallites embedded in the amorphous matrix and it has the largest improvement in MO solution degradation. These results indicate that forming nano-scale crystallites and adding H2O2 are effective methods to improve the degradation ability of Al-based glasses in azo dye solutions.

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Quinone-reducing enrichment culture enhanced the direct and mediated biotransformation of azo dye with soluble and immobilized redox mediator

Journal of Water Process Engineering ◽

10.1016/j.jwpe.2021.102424 ◽

2021 ◽

Vol 44 ◽

pp. 102424

Author(s):

Yair A. Del Ángel ◽

Refugio B. García-Reyes ◽

Lourdes B. Celis ◽

Denisse Serrano-Palacios ◽

Pablo Gortáres ◽

...

Keyword(s):

Azo Dye ◽

Enrichment Culture ◽

Redox Mediator

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PURIFICATION OF BIODIESEL USING RICE STRAW AND DIOSCOREA ALATA STARCH AS NATURAL ADSORBENTS

Jurnal Natural ◽

10.24815/jn.v19i1.12452 ◽

2019 ◽

Vol 19 (1) ◽

pp. 12-17

Author(s):

Yulidar Yulidar ◽

Saiful Saiful ◽

Ilham Maulana

Keyword(s):

Rice Straw ◽

Acid Value ◽

National Standard ◽

Dioscorea Alata ◽

Potassium Oleate ◽

Natural Adsorbents ◽

Washing Method ◽

Initial Content

Janeng starch (Dioscorea Alata) and rice straws are developed to be used as adsorbents in dry washing method to purify crude biodiesel. In this study, we evaluate the potential of rice straw and janeng starch as natural adsorbents in the purification of biodiesel that replace the role of water in absorbing contaminants from biodiesel. The SEM characterization results show that the starch adsorbent and rice straw has an open and porous surface and is evenly distributed for janeng starch. Both adsorbents, either the janeng starch or rice straw, can be applied for the purification of biodiesel. The quality of biodiesel is influenced by the amount of adsorbents used in biodiesel purification. The effectiveness of the adsorbent is shown by the decrease in free fatty acids, alkali numbers, soap numbers and turbidity levels in biodiesel. The concentration of free fatty acid oil in crude biodiesel before the purification step was 0.769 mg-KOH/g, then decreased to 0.128 mg-KOH/g after the adsorption. This acid value had been very low and met the Indonesian quality national standard for biodiesel spesically 0.50 mg-KOH/g. Either janeng starch or rice straw adsorbent was able to reduce the soap content of potassium oleate to level 53.33 ppm from the initial content of 106.67 ppm. These two natural adsorbents can be the alternative adsorbents in the purification of biodiesel that employs dry washing method.

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Role of Enzymes From Microbes in the Treatment of Recalcitrant From Industries

Research Advancements in Pharmaceutical, Nutritional, and Industrial Enzymology - Advances in Medical Technologies and Clinical Practice ◽

10.4018/978-1-5225-5237-6.ch018 ◽

2018 ◽

pp. 395-420

Author(s):

Veena Gayathri Krishnaswamy

Keyword(s):

Fresh Water ◽

Azo Dyes ◽

Azo Dye ◽

Dye Degradation ◽

Anthropogenic Activities ◽

Bacterial Degradation ◽

Wide Range ◽

Pharmaceutical Industries ◽

Degradation Of Azo Dye

The limited availability of fresh water is a global crisis. The growing consumption of fresh water due to anthropogenic activities has taken its toll on available water resources. Unfortunately, water bodies are still used as sinks for waste water from domestic and industrial sources. Azo dyes account for the majority of all dye stuffs, produced because they are extensively used in the textile, paper, food, leather, cosmetics, and pharmaceutical industries. Bacterial degradation of azo dyes under certain environmental conditions has gained momentum as a method of treatment, as these are inexpensive, eco-friendly, and can be applied to wide range of such complex dyes. The enzymatic approach has attracted much interest with regard to degradation of azo dyes from wastewater. The oxido-reductive enzymes are responsible for generating highly reactive free radicals that undergo complex series of spontaneous cleavage reactions, due to the susceptibility of enzymes to inactivation in the presence of the other chemicals. The oxidoreductive enzymes, such as lignin peroxidase, laccases, tyrosinase, azoreductase, riboflavin reductive, polyphenol oxidase, and aminopyrine n-demethylase, have been mainly utilized in the bacterial degradation of azo dye. Along with the reductive enzymes, some investigators have demonstrated the involvement in some other enzymes, such as Lignin peroxides and other enzymes. This chapter reviews the importance of enzymes in dye degradation.

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