UV light photo-Fenton degradation of polyphenols in oolong tea manufacturing wastewater

Sabaikai, Waraluk; Sekine, Makoto; Tokumura, Masahiro; Kawase, Y.

doi:10.1080/10934529.2013.838873

Cited by 25 publications

(4 citation statements)

References 30 publications

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“…Contrary, the overall reaction rate is declined with overdosing H 2 O 2 rather than the optimal concentration, since the excess peroxide reacts with the OH • radicals and hinder them rather than creating them. Additionally, perhydroxyl radicals, HO 2 , are generated which have less oxidizing efficiency than OH • radicals and this is so‐called scavenging effect (Chu, 2001; Sabaikai et al, 2014).…”

Section: Resultsmentioning

confidence: 99%

Synthesis, characterization and potential application of magnetized nanoparticles for photocatalysis of Levafix CA reactive azo‐dye in aqueous effluent

Thabet

Fouad

Ali

et al. 2021

Water & Environment J

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Dyes represent major environmental concerns since their presence in aqueous effluents posed a threat to the ecological system. This work is focused on developing a sustainable photo-Fenton strategy for efficient Levafix Blue oxidation. Nanostructured magnetite as the precursor of the oxidation technique has been synthesized via a simple co-precipitation technique. Fourier transform infrared (FTIR) spectroscopy and scanning electron microscopy (SEM) were applied to characterize the samples.The experimental dye removal data revealed that almost complete dye removal (99.9%) was attained at pH 3.0 using 800 and 40 mg/L of H 2 O 2 and magnetite reagents, respectively within 30-min of irradiation time. The process follows the first-order reaction model with endothermic and non-spontaneous oxidation reaction in nature with a low activation energy barrier of 14.29 kJ/mol. Finally, the experimental data reveals that magnetite could be easily recovered and recycled up to six treatment cycles with a removal efficiency of 71% confirms the process sustainability.

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Section: Resultsmentioning

confidence: 99%

Synthesis, characterization and potential application of magnetized nanoparticles for photocatalysis of Levafix CA reactive azo‐dye in aqueous effluent

Thabet

Fouad

Ali

et al. 2021

Water & Environment J

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“…The results showed a negligible increase from 77.5% to 78.3% in removal efficiency when H 2 O 2 dosage further increased from 100 to 120 mmol/L. It can be interpreted that the excessive H 2 O 2 acts as a scavenger of ∙OH, but the produced HO 2 ∙ (Equations ( 5 )–( 7 )) has much lower oxidation capacities [ 38 ]. Therefore, the optimum H 2 O 2 dosage was found to be 100 mmol/L for advanced treatment of the pesticide-containing wastewater by the MWEUV/Fenton:

…”

Section: Resultsmentioning

confidence: 99%

Advanced Treatment of Pesticide-Containing Wastewater Using Fenton Reagent Enhanced by Microwave Electrodeless Ultraviolet

Cheng¹,

Jing²,

Lü³

et al. 2015

BioMed Research International

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The photo-Fenton reaction is a promising method to treat organic contaminants in water. In this paper, a Fenton reagent enhanced by microwave electrodeless ultraviolet (MWEUV/Fenton) method was proposed for advanced treatment of nonbiodegradable organic substance in pesticide-containing biotreated wastewater. MWEUV lamp was found to be more effective for chemical oxygen demand (COD) removal than commercial mercury lamps in the Fenton process. The pseudo-first order kinetic model can well describe COD removal from pesticide-containing wastewater by MWEUV/Fenton, and the apparent rate constant (k) was 0.0125 min−1. The optimal conditions for MWEUV/Fenton process were determined as initial pH of 5, Fe2+ dosage of 0.8 mmol/L, and H2O2 dosage of 100 mmol/L. Under the optimal conditions, the reaction exhibited high mineralization degrees of organics, where COD and dissolved organic carbon (DOC) concentration decreased from 183.2 mg/L to 36.9 mg/L and 43.5 mg/L to 27.8 mg/L, respectively. Three main pesticides in the wastewater, as Dimethoate, Triazophos, and Malathion, were completely removed by the MWEUV/Fenton process within 120 min. The high degree of pesticides decomposition and mineralization was proved by the detected inorganic anions.

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“…Previous studies, such as the work by Tum et al [28] reported the destruction of black tea by ZnO application. Zhang et al [29] degraded black tea by applying gut microbiota; Maghanga et al [30] decolourized black tea by electrocoagulation, while Sabaikai et al [31] reported the decolourization of oolong tea species by the photo-Fenton process. To the best of the knowledge of the authors, the comparative application of both ZnO and TiO 2 under varying light sources for the abatement of rooibos and black tea have not been previously reported.…”

Section: Introductionmentioning

confidence: 99%

Treatment of Dark Humic Water Using Photocatalytic Advanced Oxidation (PAO) Processes under Visible and UV Light

et al. 2023

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The aim of the study was to investigate the application of photocatalytic advanced oxidation (PAO) for the treatment of water contaminated with dark humic material from fynbos biome plants, which cannot be treated by conventional methods. The study used a fynbos species (Aspalathus linearis) to create a model wastewater that was compared with a brew made from black tea (Camellia sinensis). Two photocatalysts (TiO2 and ZnO) and three light sources (natural, halogen light, and UV light) were tested, with and without hydrogen peroxide. The treatment of the two teas by only photolysis was observed to be minimal. The study found that natural sunlight was not effective, but a combination of ZnO and halogen lamp exhibited the best performance, with a 60% degradation in 20 min under solar irradiation. The optimum catalyst concentration was identified as 10 g/L for both photocatalysts. The influence of some process parameters showed that a combination of an optimum dose of 5 mM H2O2 and solar radiation improved the performance of TiO2 from 16 to 47%. The photocatalytic reaction data were fitted to the pseudo first and second-order kinetic models in order to exploit the kinetic process of the photo-destruction reaction. The kinetic fits showed that the degradation reaction better adhered to the second-order kinetic model when only ZnO and solar radiation were applied, regardless of the tea type employed. The application of PAO in this novel and cost-effective way has potential for the abatement of contaminated water to potable water. The use of heterojunction photocatalysts could be explored in future research to further improve the process.

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UV light photo-Fenton degradation of polyphenols in oolong tea manufacturing wastewater

Cited by 25 publications

References 30 publications

Synthesis, characterization and potential application of magnetized nanoparticles for photocatalysis of Levafix CA reactive azo‐dye in aqueous effluent

Synthesis, characterization and potential application of magnetized nanoparticles for photocatalysis of Levafix CA reactive azo‐dye in aqueous effluent

Advanced Treatment of Pesticide-Containing Wastewater Using Fenton Reagent Enhanced by Microwave Electrodeless Ultraviolet

Treatment of Dark Humic Water Using Photocatalytic Advanced Oxidation (PAO) Processes under Visible and UV Light

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