Decomposition of cyclohexanoic acid by the UV/H2O2 process under various conditions

Afzal, Atefeh; Drzewicz, Przemysław; Martin, Jonathan W.; El-Din, Mohamed Gamal

doi:10.1016/j.scitotenv.2012.03.019

Cited by 65 publications

(15 citation statements)

References 35 publications

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“…In accordance with our study, the pH had no significant effect on the degradation of cyclohexanoic acid (Afzal et al 2012) and presented a minor effect on the photodegradation of Reactive Green 19 (RG19) azo dye, when compared to the main effects of both the initial dye and H 2 O 2 concentrations (Zuorro et al 2013). The removal of the nonsignificant coefficients from Eq.…”

Section: Evaluation Of Uv-h 2 O 2 Processsupporting

confidence: 88%

“…As a result, it is commonly reported that an optimum H 2 O 2 dose enhances degradation rates of a variety of compounds and effluents (Afzal et al 2012;Alaton et al 2002;Wang et al 2001), because although high concentrations of H 2 O 2 increase the rate of HO• production, it also can act as an HO• scavenger, thus resulting in lower oxidation efficiencies. Nevertheless, no optimal [H 2 O 2 ]/COD ratio was found for the H 2 O 2 concentration range used in our investigation (from 84 to 534 mg L −1 ), indicating that H 2 O 2 dose did not reach the inhibition zone.…”

Section: Evaluation Of Uv-h 2 O 2 Processmentioning

confidence: 99%

“…In general, advanced oxidation processes (AOPs) involve the generation of hydroxyl free radicals (HO•), which are highly powerful oxidizing species [redox potential = 2.8 V ( CRC Handbook 1995)] which react nonselectively with organic and inorganic substances (Afzal et al 2012). Among the various AOPs, several advantages can be pointed out for the UV/H 2 O 2 process: (1) UV irradiation from 200 to 300 nm is a very effective way to inactivate microorganisms (Zhou and Smith 2002); (2) H 2 O 2 is the only chemical required, which has an infinite solubility in water and can be stored for use according to process demand (Legrini et al 1993;Sundstrom et al 1992); (3) the UV/H 2 O 2 process is a very cost-effective source of hydroxyl radicals, it is simple to operate, and it is readily accomplished in the existing infrastructures (Legrini et al 1993;Stefan et al 1996;Zhou et al 2012); and (4) there is no sludge production during UV/H 2 O 2 treatment, thus eliminating the need of further disposal (Smith and Frailey 1990).…”

Section: Introductionmentioning

confidence: 99%

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Treatment of hospital laundry wastewater by UV/H2O2 process

Zotesso

Cossich

Janeiro

et al. 2016

Environ Sci Pollut Res

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Hospitals consume a large volume of water to carry out their activities and, hence, generate a large volume of effluent that is commonly discharged into the local sewage system without any treatment. Among the various sectors of healthcare facilities, the laundry is responsible for the majority of water consumption and generates a highly complex effluent. Although several advanced oxidation processes (AOPs) are currently under investigation on the degradation of a variety of contaminants, few of them are based on real wastewater samples. In this paper, the UV/HO AOP was evaluated on the treatment of a hospital laundry wastewater, after the application of a physicochemical pretreatment composed of coagulation-flocculation and anthracite filtration. For the UV/HO process, a photoreactor equipped with a low-pressure UV-C lamp was used and the effects of initial pH and [HO]/chemical oxygen demand (COD) ratio on COD removal were investigated through a randomized factorial block design that considered the batches of effluent as blocks. The results indicated that the initial pH had no significant effect on the COD removal, and the process was favored by the increase in [HO]/COD ratio. Color and turbidity were satisfactorily reduced after the application of the physicochemical pretreatment, and COD was completely removed by the UV/HO process under suitable conditions. The results of this study show that the UV/HO AOP is a promising candidate for hospital laundry wastewater treatment and should be explored to enable wastewater reuse in the washing process.

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Section: Evaluation Of Uv-h 2 O 2 Processsupporting

confidence: 88%

Section: Evaluation Of Uv-h 2 O 2 Processmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Treatment of hospital laundry wastewater by UV/H2O2 process

Zotesso

Cossich

Janeiro

et al. 2016

Environ Sci Pollut Res

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“…A negative effect of chloride on the AOPs through scavenging of • OH radicals has been reported by many authors [29]. Gultekin at.…”

Section: Effect Of Organic Anionsmentioning

confidence: 76%

The effect of anions on decolorization of textile azo dye Reactive Orange 16 with UV/H2O2 process

Mitrović¹,

Radović-Vučić²,

Kostić³

et al. 2019

Adv Techol

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The effects of various organic and inorganic anions on decolorization of textile dye Reactive Orange 16 by means of hydroxyl radicals have been studied. These anions are commonly present in wastewaters from textile industry and include chloride, sulfate, carbonate/bicarbonate, nitrate and acetate anions. The experiments were conducted in the presence of different concentrations of anions and at different initial pH values in a batch photoreactor equipped with UV-C (254 nm) lamps in the presence of hydrogen peroxide. It was obtained that decolorization efficiency was significantly affected by nature and concentration of the investigated anions. An inhibitory effect of acetate anions increased with increasing in their concentration and depended on whether protonated or deprotonated forms are favored. Carbonate anion showed specific, both positive and negative influence, depending on its concentration. Influence of bicarbonate, nitrate and chloride was more prominent at their higher initial concentrations. The presence of sulfate did not have noticeable impact on decolorization of RO16 dye under investigated conditions. Ključne reči: unapređeni oksidacioni procesi, hidroksilni radikali, karbonatni anjon, acetatni anjon (ORIGINALNI NAUČNI RAD)

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“…Addition of incremental amounts of chloride to NaNO3 background anolyte increased the apparent rate constants for resorcinol oxidation from 0.26 ± 0.03 h -1 (0 mM Cl − ) to 1.2 ± 0.13 h -1 (40 mM Cl − ). Chloride has an inhibiting effect on the degradation of organic contaminants by the homogeneously formed • OH, particularly at low pH, due to the formation of radical chlorine species (Cl • , Cl2 •− ) which are weaker oxidants than • OH (Pignatello 1992, Kiwi et al 2000, Seiss et al 2001, Maciel et al 2004, Moraes et al 2004, Afzal et al 2012. The enhancing effect of chloride observed in NaNO3 anolyte can be ascribed to an increased generation of free available chlorine (Cl2/HOCl) by the electrolysis of chloride at BDD anode (Bergmann and Rollin 2007).…”

Section: Effect Of Chloride Addition On the Electrooxidation Of Resormentioning

confidence: 99%

Electrochemical Oxidation of Recalcitrant Organic Compounds using Electro-Generated Sulfate-based Oxidizing Agents

Farhat¹

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Sulfate ions have often been used as background electrolytes in electrochemical degradation of contaminants, and have generally been considered inert even when employing high oxidation power anodes such as boron-doped diamond. Boron-doped diamond (BDD) anodes are widely used in literature for investigating electrochemical oxidation of contaminants due to their excellent capability to form hydroxyl radicals as well as inorganic radicals such as chlorine, phosphate, and sulfate radicals, electrogenerated when their corresponding anions are present in the influent water. This study examined the role of sulfate ions and the potential electro-generation of sulfate-based oxidants by comparing electrooxidation rates for persistent organic contaminants at BDD anodes in the presence of sulfate or nitrate anolytes (considered as inert). The effect of the operating conditions governing this process such as anolyte concentration / conductivity, applied current density, as well as solution volume were explored in this work. The characteristics and the reactive life-time of these electro-chemically generated sulfatebased oxidizing agents were further explored by studying the oxidation extent occurring after the electric current has been switched off or via different modes of intermittent electric current as an option to improve energy efficiency. The effect of chloride ions on the sulfate-based electrooxidation processes for the removal of a natural organic matter surrogate, resorcinol, was also addressed in this work because the anodic oxidation of chloride yields oxidizing species such as chlorine / hypochlorous acid as well as chlorine/chloride radicals, and may compete with sulfate-based oxidizing species, leading to the formation of toxic organic and inorganic chlorinated compounds at higher applied potentials.The detailed investigations showed that sulfate yielded 10 -15 times higher electrooxidation rates of all target contaminants compared to the rates achieved with a nitrate anolyte at identical conductivities. The presence of specific radical quenchers (tert-butanol, methanol) reported a similar effect on diatrizoate electrooxidation rates, illustrating that hydroxyl radicals ( • OH) are most likely influencing the potential anodic formation of sulfate-based oxidizing species. Thus, these results indicate the formation of strong sulfate-derived oxidant species at BDD anodes, where the energy consumption required for a 10-fold removal of diatrizoate was reduced from 45.6 to 2.44 kWh m -3 by switching from nitrate to sulfate anolyte. This electrochemical activation of sulfate was also observed at low concentrations, relevant for many wastewaters, where even only 1.56 mM sulfate anolyte solution (3.5 mS cm -1 and 100 A m -2 ) achieved a higher removal rate than 60 mM nitrate with correspondingly higher conductivity (9.0 mS cm -1 ) and operated at double the current density (200 A m -2 ). Chloride addition to Na2SO4 inhibited the resorcinol oxidation and mineralization, unlike its addition to NaNO3 where it enhanced the ...

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Decomposition of cyclohexanoic acid by the UV/H2O2 process under various conditions

Cited by 65 publications

References 35 publications

Treatment of hospital laundry wastewater by UV/H2O2 process

Treatment of hospital laundry wastewater by UV/H2O2 process

The effect of anions on decolorization of textile azo dye Reactive Orange 16 with UV/H2O2 process

Electrochemical Oxidation of Recalcitrant Organic Compounds using Electro-Generated Sulfate-based Oxidizing Agents

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