UV light assisted decolorization of dark brown colored coffee effluent by photo-Fenton reaction

Tokumura, Masahiro; Ohta, Ayano; Znad, Hussein; Kawase, Y.

doi:10.1016/j.watres.2006.08.012

Cited by 88 publications

(53 citation statements)

References 20 publications

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“…2). In general, the TOC removal results compare well with previous reported organic removals (which are often around 85 % (Bejankiwar et al 2003;Tokumura et al 2006;Zayas et al 2007;Tokumura et al 2008;Kondo et al 2010;Yamal-Turbay et al 2012)). However, what is noteworthy in this research is that high levels of mineralization were observed within a reasonably short time frame, which is important given that real-world, coffee pulping wastewater was being used (which, by its very nature, is considerably more complex than its synthetic counterpart).…”

Section: Organic Matter Removalsupporting

confidence: 88%

“…The excellent removal results for the EAOPs can be explained by the continuous formation of hydroxyl radicals; in contrast to chemical Fenton systems which can be limited by a decline in the available hydrogen peroxide, even though H 2 O 2 aliquots were added during the reaction. Moreover, it was observed that the addition of Fe 2+ caused a dark color in the reaction medium and that this was most evident in the chemical Fenton treatment Tokumura et al (2006) who reported an increase in absorbance in the first few seconds after Fenton reagents were added to a synthetic coffee sample. Due to the complex nature of the waste, it is difficult to identify intermediate compounds and other byproducts formed during the oxidation reactions.…”

Section: Color Removalmentioning

confidence: 99%

“…Previous studies investigating AOPs for the treatment of coffee wastewater seem to have focused on either the application of AOPs after biological or physical-chemical pre-treatment methods (Bejankiwar et al 2003;Zayas Pérez et al 2007;Kondo et al 2010); or the use of synthetic, instant-coffee solutions (Tokumura et al 2006(Tokumura et al , 2008Yamal-Turbay et al 2012;Satori and Kawase 2014). Further research is needed to achieve a robust, stand-alone system capable of treating a real coffee wastewater.…”

mentioning

confidence: 99%

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Discoloration and Organic Matter Removal from Coffee Wastewater by Electrochemical Advanced Oxidation Processes

Villanueva-Rodríguez

Bello-Mendoza

Wareham

et al. 2014

Water Air Soil Pollut

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The coffee agro-industry generates a large volume of wastewater that is notable for its high organic strength as well as its color content. Due to the seasonal nature of the harvest (3-4 months per year), this particular industrial waste needs a treatment method that is both reliable and fast (in terms of start-up time). As part of investigating a system capable of treating a coffee wastewater, this research evaluated four electrochemical advanced oxidation processes (EAOPs) using boron-doped diamond (BDD) electrodes. The processes were anodic oxidation (AO), anodic oxidation with electrogenerated H 2 O 2 (AO-H 2 O 2 ), electro-Fenton (EF), and photoelectro-Fenton (PEF). Experimental conditions were as follows: 40 mA cm −2 current density (all EAOPs), 0.3 mmol Fe 2+ L −1 (Fenton systems), 300 mL air min −1 (AO-H 2 O 2 , EF, PEF), and 500 μW cm −2 UV irradiation (photo-Fenton systems). The performance of the four EAOP treatment methods (in terms of color and organic carbon removal) was compared against two conventional chemical oxidation methods, namely, Fenton and photo-Fenton. The research indicated that the four EAOPs were better at removing color (89-93 %) and total organic carbon (TOC) (73-84 %) than the respective chemical Fenton (58 and 4.8 %) and photo-Fenton (61 and 7 %) methods. The trend in performance was as follows: AO-H 2 O 2 >AO>PEF≈EF. It appeared that the ferrous iron reagent formed a dark-colored complex with some coffee components, diminishing the effect of Fenton reactions. In addition, the dark color of the wastewater limited the effect of light in the UV-Fenton processes. Analysis showed that acceptable levels of Fe 2+ (0.3 mmol L −1 ) and energy (0.082-0.098 kWh g −1 TOC) were required by the EAOPs after 4-h treatment time. In conclusion, the use of electrochemical methods (equipped with BDD electrodes) seems a promising method for the effective treatment of coffee wastewaters.

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Section: Organic Matter Removalsupporting

confidence: 88%

Section: Color Removalmentioning

confidence: 99%

mentioning

confidence: 99%

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Discoloration and Organic Matter Removal from Coffee Wastewater by Electrochemical Advanced Oxidation Processes

Villanueva-Rodríguez

Bello-Mendoza

Wareham

et al. 2014

Water Air Soil Pollut

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“…5). Numerous works have indicated that the rate of degradation of organic compounds increases with H 2 O 2 concentration up to a threshold; as the H 2 O 2 concentration increases further, the degradation efficiency declines as H 2 O 2 scavenges HO • , when H 2 O 2 is present at a high concentration [13,19,20], generating hydroperoxyl radicals, which have lower oxidation capacity than hydroxyl radicals. Accordingly, the dose of H 2 O 2 in the UV/ H 2 O 2 system must be carefully controlled.…”

Section: Resultsmentioning

confidence: 99%

Decolorization of C.I. reactive red 198 in UV/oxidant and UV/TiO2/oxidant systems

2011

Reac Kinet Mech Cat

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In this study, UV/oxidant and UV/TiO 2 /oxidant systems were employed to treat textile wastewater. The parent compound was C.I. reactive red 198 (RR198). The selected oxidants were H 2 O 2 , Na 2 S 2 O 8 , NaBrO 3 , and NaIO 4 . The effects of oxidant dosage (1-24 mM), wavelength of UV (254 and 365 nm) and radical scavenger addition (C 2 H 5 OH) were determined in UV/oxidant systems. The experimental results revealed that all oxidants effectively decolorized RR198 under 254 nm irradiation; however, only Na 2 S 2 O 8 and NaIO 4 can decolorize RR198 under 365 nm irradiation. The decolorization rates fit a pseudo-first order reaction model. Under 254 nm irradiation and 6 mM oxidant addition, the decolorization rate constants (k) of H 2 O 2 , Na 2 S 2 O 8 , NaBrO 3 , and NaIO 4 for RR198 were 10.24, 17.93, 13.37, and 11.90 h -1 . Under 365 nm irradiation, 1 g/L TiO 2 and 1 mM NaIO 4 addition, the k values of the UV/TiO 2 , UV/NaIO 4 , and UV/TiO 2 /NaIO 4 systems were 0.50, 0.52, and 11.67 h -1 . The inhibition of RR198 decolorization by the addition ethanol indicates that the primary decolorization pathway involves hydroxyl radicals in UV/H 2 O 2 and UV/Na 2 S 2 O 8 systems, and that oxidation by other radicals is probably important in UV/NaBrO 3 and UV/NaIO 4 systems.

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“…, then •OH generated in the reactions (Eq. 3, 4 and 5) can react with target phenol to produce the desired products [27][28]. According to the proposed mechanism, the selective hydroxylation phenol in presence of PG8 catalyst under irradiation with UV light can be well explained without involving in high-valence iron-oxo or iron-peroxo complexes [29].…”

Section: The Mechanism Of Photocatalytic Hydroxylationmentioning

confidence: 93%

Photocatalytic Hydroxylation of Phenol to Catechol and Hydroquinone by Using Organic Pigment as Selective Photocatalyst

Shi¹,

Zhang²,

An³

et al. 2012

COC

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Abstract:The application of photocatalytic reactions in organic synthesis has attracted extensive attentions because of recent developments in environmentally benign synthetic processes. For the first time, an organic pigment (C. I. Pigment Green 8) was used as selective photocatalyst to accomplish the photocatalytic hydroxylation of phenol to catechol (CAT) and hydroquinone (HQ) with the assistance of UV irradiation at room temperature. The prepared photocatalysts were characterized by FT-IR spectrum and UV-visible diffuse reflectance spectroscopy (UV-vis DRS), and the result found that the photocatalyst exhibits excellent adsorption ability both in the ultraviolet and visible light region. The effects of various affecting-parameters, such as catalyst amount, H2O2 amount, co-solvents and reaction time, on the photocatalytic hydroxylation of phenol were studied to optimize the reaction conditions. The desired products (CAT and HQ) on the photocatalyst can be facilitated with an increase in the selectivity. In this study, the conversion efficiency of phenol could reach high up to 87.8% with a total selectivity of 73.0% as well as the yield of 37.0% and 27.4% for CAT and HQ, respectively. The reaction is a photo-Fenton like process, and the iron ions cycle between Fe 2+ and Fe 3+ occurs with the light irradiation.

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UV light assisted decolorization of dark brown colored coffee effluent by photo-Fenton reaction

Cited by 88 publications

References 20 publications

Discoloration and Organic Matter Removal from Coffee Wastewater by Electrochemical Advanced Oxidation Processes

Discoloration and Organic Matter Removal from Coffee Wastewater by Electrochemical Advanced Oxidation Processes

Decolorization of C.I. reactive red 198 in UV/oxidant and UV/TiO2/oxidant systems

Photocatalytic Hydroxylation of Phenol to Catechol and Hydroquinone by Using Organic Pigment as Selective Photocatalyst

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