Microwave-assisted catalytic wet peroxide oxidation. Comparison of Fe catalysts supported on activated carbon and ?-alumina

Garcia-Costa, Alicia L.; Zazo, Juan A.; Rodrı́guez, Juan J.; Casas, José A.

doi:10.1016/j.apcatb.2017.06.058

Cited by 49 publications

(14 citation statements)

References 38 publications

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“…In fact, when a metal-based catalyst such as Fe/AC or Fe/Al 2 O 3 is used, the activity is much higher (up to one order of magnitude). In this sense, initial TOC abatement rates of 72 mg TOC L −1 min −1 and 32 mg TOC L −1 min −1 , were obtained with those catalysts, respectively, in the CWPO of phenol under similar operating conditions [37]. It is clear that in these cases, the coverage of the active sites even with catalytically active condensation by-products would unavoidably lead to lower catalytic activities.…”

Section: Oxidation Experimentsmentioning

confidence: 68%

Condensation By-Products in Wet Peroxide Oxidation: Fouling or Catalytic Promotion? Part I. Evidences of an Autocatalytic Process

et al. 2019

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The present work is aimed at the understanding of the condensation by-products role in wet peroxide oxidation processes. This study has been carried out in absence of catalyst to isolate the (positive or negative) effect of the condensation by-products on the kinetics of the process, and in presence of oxygen, to enhance the oxidation performance. This process was denoted as oxygen-assisted wet peroxide oxidation (WPO-O2) and was applied to the treatment of phenol. First, the influence of the reaction operating conditions (i.e., temperature, pH0, initial phenol concentration, H2O2 dose and O2 pressure) was evaluated. The initial phenol concentration and, overall, the H2O2 dose, were identified as the most critical variables for the formation of condensation by-products and thus, for the oxidation performance. Afterwards, a flow reactor packed with inert quartz beads was used to facilitate the deposition of such species and thus, to evaluate their impact on the kinetics of the process. It was found that as the quartz beads were covered by condensation by-products along reaction, the disappearance rates of phenol, total organic carbon (TOC) and H2O2 were increased. Consequently, an autocatalytic kinetic model, accounting for the catalytic role of the condensation by products, provides a well description of wet peroxide oxidation performance.

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Section: Oxidation Experimentsmentioning

confidence: 68%

Condensation By-Products in Wet Peroxide Oxidation: Fouling or Catalytic Promotion? Part I. Evidences of an Autocatalytic Process

et al. 2019

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“…The efficiency of hydrogen peroxide is one of the parameters that requires optimization in CWPO processes. The hydrogen peroxide and catalyst are critical parameters which determine the optimal production and consumption of the generated hydroxyl radicals; thus, for example, the use of optimal doses will reduce the formation of parasitic reactions (Equations (7)-(9), (11)- (14)) and the generation of oxygen and water [37]. The stoichiometry of the reaction clearly indicates that only 32 moles of hydrogen peroxide is typically required for one mole of NAP; however, the catalytic reaction for degradation of NAP requires an extra amount of hydrogen peroxide in order to shift the equilibrium towards CO 2 and H 2 O formation.…”

Section: Combined Effect Of Hydrogen Peroxide Dose and Ph On Nap Removalmentioning

confidence: 99%

“…• OH + Organics → Intermediates → Inorganics (15) In this particular case, the excess in the H 2 O 2 concentration led to a decrease in the degradation of NAP. This is attributed to the generation of secondary reactions that usually occur, such as the reaction of • OH with H 2 O 2 and the reaction of two molecules of • OH (Equations (13) and (14)).…”

Section: Effect Of Temperaturementioning

confidence: 99%

“…These properties make it difficult to be degraded in the conventional WWTPs that usually work near the neutral pH. As a consequence, NAP would pass through these conventional treatment processes and end up in the water environment [14]. In this sense, the effectiveness of the removal of NAP from wastewater by different treatments, such as adsorption in activated process, biological degradation, photolysis, ozonation/H 2 O 2 , and adsorption on activated carbon, were 50-80%, no data, 99-100%, 98%, and 52%, respectively [2].…”

Section: Introductionmentioning

confidence: 99%

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Optimization Parameters, Kinetics, and Mechanism of Naproxen Removal by Catalytic Wet Peroxide Oxidation with a Hybrid Iron-Based Magnetic Catalyst

et al. 2019

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This work presents a study of the assessment of the operating parameters of the catalytic wet peroxide oxidation (CWPO) of naproxen (NAP) using magnetite/multi-walled carbon nanotubes (Fe3O4/MWCNTs) as a catalyst. The effect of pH, temperature, and H2O2 dosage on CWPO process was evaluated by using the response surface model (RSM), allowing us to obtain an optimum NAP removal of 82% at the following operating conditions: pH = 5, T = 70 °C, [H2O2]0 = 1.5 mM, and [NAP]0 = 10.0 mg/L. Therefore, NAP degradation kinetics were revealed to follow a pseudo-second-order kinetic model, and an activation energy value of 4.75 kJ/mol was determined. Adsorption and using only H2O2 experiments, both considered as blank tests, showed no significant removal of the pollutant. Moreover, Fe3O4/MWCNTs material exhibited good recyclability along three consecutive cycles, finding an average NAP removal percentage close to 80% in each cycle of 3 h reaction time. In addition, the scavenging tests confirmed that the degradation of NAP was mainly governed by •OH radicals attack. Two reaction sequences were proposed for the degradation mechanism according to the detected byproducts. Finally, the versatility of the catalyst was evidenced in the treatment of different environmentally relevant aqueous matrices (wastewater treatment plant effluent (WWTP), surface water (SW), and a hospital wastewater (HW)) spiked with NAP, obtaining total organic carbon (TOC) removal efficiencies after 8 h in the following order: NAP-SW > NAP-HW > NAP-WWTP.

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“…Designing carbon‐based composites with a high adsorption capacity provided with new features could have a significant impact on real‐scale applications . The purpose of the present study was to determine the efficiency of the photo‐Fenton‐peroxone system on the degradation of organic compounds in an aqueous solution using Fe‐embedded activated carbon prepared through a simple and inexpensive method.…”

Section: Introductionmentioning

confidence: 99%

Photo‐Fenton‐peroxide process using FE (II)‐embedded composites based on activated carbon: Characterization of catalytic tests

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Cost-efficient Fenton-like catalysts for the removal of organic molecules in aqueous solutions were elaborated by a simple process. Porous activated carbons (ACs) were directly impregnated with a precursor solution using the wet impregnation method. Their efficiency as Fenton-like catalysts was studied. Photo-Fenton tests were performed to establish the performance of the prepared Fe-impregnated activated carbons in relation to the degradation of an organic pollutant (Indigo Carmine) model in aqueous solution, under different conditions. Photo-catalytic tests were carried out by means of a laboratory photo-reactor (UV-Consulting Peschl).The influence of several parameters such as solution pH value, initial concentration of the model pollutant, and hydrogen peroxide dose on the process performance was investigated. The ACs and prepared catalysts were characterized by nitrogen adsorption-desorption isotherms at 77 K, SEM, and thermogravimetric analyses. The total Fe content of the synthesized composites was estimated by the phenanthroline method using UV-vis spectrophotometry. The results show an increase in the degradation rate when the heterogeneous photo-Fenton process is conducted with an ozone generating UV lamp. K E Y W O R D Sactivated carbon, anionic dye, composite, Fenton

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Microwave-assisted catalytic wet peroxide oxidation. Comparison of Fe catalysts supported on activated carbon and ?-alumina

Cited by 49 publications

References 38 publications

Condensation By-Products in Wet Peroxide Oxidation: Fouling or Catalytic Promotion? Part I. Evidences of an Autocatalytic Process

Condensation By-Products in Wet Peroxide Oxidation: Fouling or Catalytic Promotion? Part I. Evidences of an Autocatalytic Process

Optimization Parameters, Kinetics, and Mechanism of Naproxen Removal by Catalytic Wet Peroxide Oxidation with a Hybrid Iron-Based Magnetic Catalyst

Photo‐Fenton‐peroxide process using FE (II)‐embedded composites based on activated carbon: Characterization of catalytic tests

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