Kinetics and mechanism of the oxidation of Coomassie Brilliant Blue-R dye by hypochlorite and role of acid therein

Nadupalli, Srinivasu; Dasireddy, Venkata D.B.C.; Koorbanally, Neil A.; Jonnalagadda, Sreekantha B.

doi:10.17159/0379-4350/2015/v68a13

Cited by 8 publications

(6 citation statements)

References 31 publications

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“…As water is present in the reaction mixture in a large excess as compared with the amount of intermediate A , the reaction is proposed to follow pseudo-first-order kinetics. The pseudo-first-order kinetics behavior of hypochlorite was also observed by other researchers. − …”

Section: Resultssupporting

confidence: 77%

Selectivity of Oxidizing Agents toward Axial and Equatorial Hydroxyl Groups

Kašpar

Kudová

2022

J. Org. Chem.

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A total of 16 oxidizing reagents were screened to compare their oxidation selectivities for axial and equatorial hydroxyl moieties using steroidal methyl chenodeoxycholate, methyl deoxycholate, and 4-tert-butylcyclohexanol (cis/trans 1:1 mixture). These compounds were selected for their stable chair conformations. The results of our study demonstrated that, for the oxidation of a scaffold bearing both axial and equatorial hydroxyl groups, nitroxide-radical-based reagents should be the first choice if oxidation of the equatorial hydroxyl group is needed and Stevens or Dess−Martin reagents should be the first choice for the preferential oxidation of the axial hydroxyl group.

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Section: Resultssupporting

confidence: 77%

Selectivity of Oxidizing Agents toward Axial and Equatorial Hydroxyl Groups

Kašpar

Kudová

2022

J. Org. Chem.

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“…45,46 Dyes have been shown to degrade to small chlorinated organic compounds with molar masses as low as 234 g/mol and with a less branched structure compared to the original dye. 47,48 Similarly, natural organic matter, such as humic acid, has exhibited ring-opening reactions and degradation to low molecular weight trihalomethanes such as chloroform (MW = 119.4 g/mol) under chlorinating conditions. 46,49 Based on the degradation of these organic foulants into smaller byproducts, the observed improvement in permeance following hypochlorite treatment can be attributed to the degradation of the previously adsorbed organic material from within the GO galleries of the membrane.…”

Section: Resultsmentioning

confidence: 99%

“…Cleaning with 100 ppm of hypochlorite exhibits permeance recoveries of 90.3, 98.2, and 94.6% for membranes fouled with MB, TA, and BSA, respectively. There is no doubt that the oxidizing capacity of this reagent is the primary factor for the excellent permeance recovery, but the role of the ionic strength of the hypochlorite solution cannot be neglected, as it can result in changed electrostatic interactions at the adsorbed foulant–membrane interface and deliver a positive contribution to the removal of foulants from the membrane surface. , Such effects have been attributed to a variety of reasons including the increase in the hydration repulsion forces between the membrane and foulant molecules, which decreases the adsorption and deposition of foulants on the membrane surface. − Alternatively, the improvement could also be attributed to the breakdown of the organic foulant into smaller byproducts that can be easily removed from the membrane by rinsing or permeating through the GO membrane. , Dyes have been shown to degrade to small chlorinated organic compounds with molar masses as low as 234 g/mol and with a less branched structure compared to the original dye. , Similarly, natural organic matter, such as humic acid, has exhibited ring-opening reactions and degradation to low molecular weight trihalomethanes such as chloroform (MW = 119.4 g/mol) under chlorinating conditions. , Based on the degradation of these organic foulants into smaller byproducts, the observed improvement in permeance following hypochlorite treatment can be attributed to the degradation of the previously adsorbed organic material from within the GO galleries of the membrane.…”

Section: Resultsmentioning

confidence: 99%

Efficient Permeance Recovery of Organically Fouled Graphene Oxide Membranes

Meragawi

Akbari

Hernandez

et al. 2019

ACS Appl. Bio Mater.

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The emergence of facile approaches for the large-scale production of graphene oxide (GO) membranes necessitates a clearer understanding of their potential to foul and, more importantly, strategies for efficient recovery of membrane performance following fouling. Here, we systematically investigated the feasibility of water, ethanol, and hypochlorite as cleaning agents to remove organic foulants over a GO membrane. Among them, 100 ppm hypochlorite solution showed a remarkable ability to remove bovine serum albumin (BSA) and could recover the membrane flux up to 98% after five cycles of BSA filtration and cleaning. The potential of hypochlorite was also demonstrated for permeance recovery during molecular filtration of tannic acid and methyl blue. Scanning electron microscopy, attenuated total reflectance-Fourier transform infrared spectroscopy (ATR-FTIR), and X-ray diffraction (XRD) analyses were used to study the oxidative effects of hypochlorite on the GO membrane, and it was determined that exposure to higher concentrations of hypochlorite (>1000 ppm) degrades the structure of GO membrane and deteriorates the membrane performance after three cycles of cleaning. The studies demonstrate that the use of a modest concentration of hypochlorite is effective in restoring permeance of this class of high flux nanofiltration membranes.

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“…The observed fractional order reaction for [H + ] indicates that acid may not be directly participating in the rate-determining step. [40] It was reported that different oxybromo species (HBrO 3 , H 2 BrO 3 + and BrO 2…”

Section: Effect Of Acid Concentrationmentioning

confidence: 99%

“…The plot of lnk obs vs ln[H + ] in Figure 6 is linear with a slope of 0.27 (R 2 =0.9875). The observed fractional order reaction for [H + ] indicates that acid may not be directly participating in the rate‐ determining step [40] . It was reported that different oxybromo species (HBrO 3 , H 2 BrO 3 + and BrO 2 + ) exist in the solution depending on the pH of the medium, which competes with BrO 3 − in the oxidation of dye [27] …”

Section: Introductionmentioning

confidence: 99%

Chemical Degradation and Decolorization of Reactive Black B With an Inorganic Oxidant in Acidic Medium

et al. 2022

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Due to the wide applications of the Reactive Black B (RB−B) in textile industries, it is largely present within the aqueous environment which is a serious environmental threat. Previous studies were unsuccessful to completely remove the color of RB−B from the contaminated environment. In this work, the decolorization of aqueous solutions with RB−B was performed by Potassium bromate. It was found to be a promising oxidizing agent for chemical degradation of organic pollutant. The decolorization and degradation of Reactive Black B by potassium bromate in an aqueous acidic medium was carried out at 591 nm spectrophotometrically at laboratory scale. The reaction was studied under pseudo order conditions having concentration of BrO3− in excess than dye. Under constant conditions, the reaction was found to be first order with respect to both oxidant and reductant. The kinetic salt effect of added salt for the determination of reactive species in the rate‐determining step showed that the rate of reaction is directly related to the increasing concentration of salt, suggesting that two same charged species are involved in the rate‐determining step. Activation parameters were also calculated for the reaction. The highest decolorization percentage of RB−B (99 %) was obtained showing almost complete removal of color of dye from aqueous medium. The proposed degradation of RB−B with bromate was confirmed by qualitative and analytical tests (TDS, EC, UV‐Visible and FTIR spectroscopy).

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Kinetics and mechanism of the oxidation of Coomassie Brilliant Blue-R dye by hypochlorite and role of acid therein

Abstract: The kinetics of the oxidation of a triphenylmethane dye, Brilliant Blue-R (BB -Na + ), in aqueous solution by hypochlorite as a func-

Cited by 8 publications

References 31 publications

Selectivity of Oxidizing Agents toward Axial and Equatorial Hydroxyl Groups

Selectivity of Oxidizing Agents toward Axial and Equatorial Hydroxyl Groups

Efficient Permeance Recovery of Organically Fouled Graphene Oxide Membranes

Chemical Degradation and Decolorization of Reactive Black B With an Inorganic Oxidant in Acidic Medium

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