Kinetics of the oxidative degradation of thionine dye by hydrogen peroxide catalyzed by supported transition metal ions complexes

Gemeay, Ali H.; Mansour, Ikhlas A.; El-Sharkawy, Rehab G.; Zaki, Ahmed B.

doi:10.1002/jctb.917

Cited by 28 publications

(15 citation statements)

References 53 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Consequently the oxidized form of MG will remain in the reaction mixture. The rate of reduction favored at alkaline pH may be due to the generation of OH -ion according to the following reaction: The reactive species of urea in alkaline medium [(NH 2 ) 2 COH ＋ ] after hydrolysis generates one proton as mentioned in above equation, which is believed to be abstracted by dye and therefore reduction of dye can easily take place in alkaline solution according to the following Eq. (1).…”

Section: Resultsmentioning

confidence: 99%

See 1 more Smart Citation

Kinetics and Mechanism Study of Chemical Treatment of Methylene Green by Urea

2010

View full text Add to dashboard Cite

The kinetics and mechanism studies, for the reduction of methylene green (MG) by urea, in acidic and alkali media, were studied at λ max ＝652.8 nm by monitoring the depletion in MG concentration. The reaction was carried out by UV radiation, with variable dye concentration, reducing agent (urea), acid and base under different additive ions that are very common in dye waste water. The reduction followed pseudo first-order kinetics with respect to different anions, cations, dye, reductant and OH -ion concentrations. It was found that most of the cations tested showed the inhibitory effect on dye decoloration, due to the formation of insoluble precipitate and followed the orderTested anions showed that the dye decoloration was significantly accelerated and followed the order ClA mechanistic model involving generation of a complex of dye with ions was proposed.

show abstract

Section: Resultsmentioning

confidence: 99%

“…Their breakdown products may be toxic in nature and their removal from industrial effluents is a major environmental problem. [1][2][3][4][5] In fact many of these dyes have shown hazardous properties and are toxic in nature due to aromatic rings present in them. Strong color is the most visual characteristic of textile waste water.…”

Section: Introductionmentioning

confidence: 99%

Kinetics and Mechanism Study of Chemical Treatment of Methylene Green by Urea

2010

View full text Add to dashboard Cite

show abstract

“…To date, the kinetics of the oxidative degradation of azure B and thionine by cerium(IV) has not been studied; the thionine mineralization using only H 2 O 2 has been reported by Gemeay et al [27].…”

Section: Introductionmentioning

confidence: 97%

Sulfuric acid controlled oxidative degradation of azure B and thionine dyes by cerium(IV)

Katafias

Fenska

2011

Int J of Chemical Kinetics

View full text Add to dashboard Cite

Azure B (AB) and thionine (TH) cationic phenothiazyne dyes undergo an oxidative degradation by cerium(IV) in sulfuric acid media. TLC analysis of the reaction mixture containing an excess of the oxidant has shown the presence of thionine and/or methylene violet (Bernthsen) and other unidentified species. The kinetics of (i) two AB oxidation steps, namely the formation of a colored radical and its further decomposition, and (ii) the TH disappearance was studied using visible absorption spectroscopy combined with a stopped-flow method. Generation of the AB radical was confirmed by continuous flow electron paramagnetic resonance (EPR) spectroscopy. The reactions are first order in the total dye concentration, [S]. The kinetics of the studied systems is described by a common general rate law:

show abstract

“…Chemical oxidation technologies that constitute the use of oxidizing agents such as H 2 O 2 exhibit lower rates of degradation compared with processes based on HO· free radicals [30][31][32][33]. Addition of a catalyst to the system containing H 2 O 2 may lead to the generation of hydroxyl radicals, which are powerful oxidizing agents with redox potential 2.33 V and exhibit faster rates of the degradation reaction than those using conventional oxidants [34][35][36][37][38][39][40].…”

Section: Introductionmentioning

confidence: 99%