Fenton Oxidation Process Research Articles

New Approach of Integrated Advanced Oxidation Processes for the Treatment of Lube Oil Processing Wastewater

The treatment of lube oil processing industrial wastewater has been proposed by advanced oxidation processes such as Fenton and electro Fenton (EF) oxidation processes. The method of EF was further extended to homogeneous electro Fenton (Homo-EF) and heterogeneous electro Fenton (Hetero-EF) method of treatments. Three different types of anode materials were selected for the electrochemical oxidation against graphite as a cathode, i.e. SS304/graphite, graphite/graphite and Ti-MMO/graphite. Among the studied methods of treatment, the Hetero-EF performed by Ti-MMO/graphite electrode system showed maximum COD removal efficiency than the other electrode systems. The optimized conditions for the Hetero-EF by Ti-MMO/graphite were observed to be electrochemical oxidation time 120 min, solution pH 2.5, potential 7.5 V. Further, the instrumental analysis of UV–visible spectrophotometer confirmed the removal of organic concentration from lubricating oil processing wastewater.

Enhancing the Removal of Sorbed Crude Oil from Soil Through Multiple Oxidation Steps in Stepwise Fenton Processes

ABSTRACTThe stepwise Fenton oxidation process, in which hydrogen peroxide (H2O2) is added in a step-by-step manner instead of at the beginning, can achieve better sorbed crude oil removal effects. The results showed that if a high ratio of sorbed total petroleum hydrocarbon (TPH) was present in soil samples S1 (100%, initial TPH: 10,009 mg/kg) and S2 (94.2%, initial TPH: 4850 mg/kg), the TPH was oxidized in each step. In addition, the total TPH removal efficiency was 49.6% compared with the 27.9% achieved in conventional Fenton oxidation in which all H2O2 was added at the beginning. Nevertheless, when the ratio of sorbed TPH in the soil sample S3 was low (45.3%, initial TPH: 2850 mg/kg), the TPH removal efficiency was 18.9%, which was slightly higher than 18.2% achieved in the conventional Fenton process because if the sorbed TPH concentration was low, the sorbed TPH was mainly removed in the first step. The second and the third step resulted in long-chain alkanes entering the aqueous phase rather than removing them from the soil, which posed environmental risk. Therefore, it is clear that stepwise Fenton oxidation could improve sorbed TPH removal efficiency when the sorbed TPH concentration in the soil is high.

Large Laboratory-Plant application for the treatment of a Tannery wastewater by Fenton oxidation: Fe(II) and nZVI catalysts comparison and kinetic modelling

Abstract This study reports a comparison among Conventional Fenton oxidation (CF) and Heterogeneous Fenton oxidation (HF) processes performed at large lab-scale on a Tannery Wastewater (TW). The heterogeneous Fenton process was carried out by using self lab-prepared nano zero-valent iron particles as solid catalyst. Two different catalyst/oxidant (Cat/Ox) (w/w) ratio were examined: a study on the pH solution influence on the process efficiency, monitoring the COD, TP, H2O2 and Cr(VI) variation over the reaction time was carried out. The process was conducted for 10 h in batch mode for the first 2 h, followed by 8 h in continuous mode. HF demonstrated better performance, with respect to CF, towards both the removal of Chemical Oxygen Demand (COD), up to 75.5 ± 2.1%, and Total Polyphenols (TP), up to 85.1 ± 0.7%, from the TW. The CF optimal operating parameters were Cat/Ox (w/w) = 0.2 and pH = 2.5 whereas to maximize the HF efficiency a larger Cat/Ox (w/w) ratio, i.e. 0.5, was necessary. In addition, a lower amount of iron sludge was produced by HF with respect to CF (17.5–21.6%). Finally, a kinetic model on the reactions occurring in the HF/TW system was proposed and successfully used to fit experimental data.

Mechanism and identification of reaction byproducts for the degradation of Chloramphenicol drug in heterogeneous photocatalytic process

The present work investigated the degradation behavior of chloramphenicol (CHPL) drug at a high concentration in the UV-TiO2 photocatalytic (UVPC) process to compare the performance of cleavage of CHPL molecule and total organic carbon (TOC) reduction. The reduction in TOC was mostly resulted from the cleavage of C-C homolytic bond which was in the accordance of LC-MS spectra. The TOC removal was trailed by 23.19% than CHPL with 100 mgL−1 using TiO2 1.25 gL−1, pH 3, and irradiation time of 45 min. The mechanistic routes of CHPL decomposition in the UVPC process are proposed and its synergy in the Fenton oxidation process is also explored. Total seven intermediates appeared in the mass spectra within the mass to charge ratio of 100–400. The proposed mechanism implied that intermediates were mostly originated by the decomposition of amide chain of CHPL molecule. The antimicrobial activity of CHPL towards the inactivation of E. coli XL 10GOLD was decreased by 67.4% after 45 min of decomposition.

Exploring the fate and oxidation behaviors of different organic constituents in landfill leachate upon Fenton oxidation processes using EEM-PARAFAC and 2D-COS-FTIR

In this work, the changes of different organic constituents in landfill leachate were tracked in Fenton oxidation processes with different operation parameters including H2O2 doses, pH, and the ratios of [H2O2]/[Fe] via fluorescence excitation emission matrix – parallel factor analysis (EEM-PARAFAC) and two-dimensional correlation spectroscopy (2D-COS). One tryptophan-like (C1), one fulvic-like (C2), and one humic-like (C3) components were identified in the leachates. The removal behaviors of the individual fluorescent components were dependent upon the operation conditions, suggesting the existence of unique characteristics with respect to the responses to the oxidation mechanisms, which were likely altered by different operation conditions. For all tested conditions, a greater extent of removal was consistently found for C3 versus C1 and C2 except for the relatively high pH ranges (>6.0), in which C2 presented the highest removal rates. 2D-COS combined with synchronous fluorescence spectra exhibited the preferential oxidation sequence in the order of C3 > C1 > C2 with higher H2O2 doses. 2D-COS coupled with Fourier transform infrared (2D-COS-FTIR) showed that aromatic functional groups were initially oxidized, followed by the removal of carboxylic groups and the formation of inorganic functional groups and aldehyde or ketonic groups. Hetero 2D-COS maps further revealed the close association between the aromatic groups and C3, and between the carboxylic groups and C1. This study utilizing 2D-COS provided new insights into the dynamic behavior of heterogeneous landfill leachate in Fenton oxidation processes under varying operation conditions.

Treatment of wastewater containing cytotoxic drugs by CoFe2O4 nanoparticles in Fenton/ozone oxidation process

ABSTRACTNano-sized cobalt-substituted magnetite has been synthesized and used as a heterogeneous Fenton catalyst for the removal of anticancer drug Flutamide (FLU) from a solution with a concentration of 150 μM. By using response surface methodology at the optimal conditions of Fenton oxidation (FO) process, 67.7% FLU removal was obtained. In order to increase the removal efficiency of the drug, ozonation was applied in combination with FO process. Maximum FLU removal (93.0%) was obtained using 0.6 g O3 l−1h−1 and 163 mg L−1 of the catalyst. The results indicate that the proposed method is efficient for the degradation of cytotoxic drugs.

Sequential application of Fenton and ozone-based oxidation process for the abatement of Ni-EDTA containing nickel plating effluents

Treatment of Ni-EDTA in industrial nickel plating effluents was investigated by integrated application of Fenton and ozone-based oxidation processes. Determination of integrated sequence found that Fenton oxidation presented higher apparent kinetic rate constant of Ni-EDTA oxidation and capacity for contamination load than ozone-based oxidation process, the latter, however, was favorable to guarantee the further mineralization of organic substances, especially at a low concentration. Serial-connection mode of two oxidation processes was appraised, Fenton effluent after treated by hydroxide precipitation and filtration negatively affected the overall performance of the sequential system, as evidenced by the removal efficiencies of Ni2+ and TOC dropping from 99.8% to 98.7%, and from 74.8% to 66.6%, respectively. As a comparison, O3/Fe2+ oxidation process was proved to be more effective than other processes (e.g. O3-Fe2+, O3/H2O2/Fe2+, O3/H2O2-Fe2+), and the final effluent Ni2+ concentration could satisfied the discharge standard (<0.1 mg L−1, China) under the optimal conditions (H2O2 dosage of 1.0 mL L−1, Fe2+: H2O2 mole ratio of 1.46, and reaction time of 10 min for Fenton reaction, initial influent pH of 3.0, O3 dosage of 252 mg L−1, Fe2+ of 150 mg L−1, and reaction time of 30 min for O3/Fe2+ oxidation). Furthermore, pilot-scale test was carried out to study the practical treatability towards the real nickel plating effluent, revealing the effective removal of some other co-existence contaminations. And Fenton reaction has contributed most, with the percentage ranging from 72.41% to 93.76%. The economic cost advantage made it a promising alternative to the continuous Fenton oxidation.

Degradation of Crystal Violet Dye by Fenton and Photo-Fenton Oxidation Processes

Abstract The oxidative degradation of CV dye in aqueous media has been evaluated using Fenton (Fe2+/H2O2) and photo-Fenton (Fe2+/H2O2/UV) processes. Various operational parameters like H2O2 dosages, Fe2+ dosages and [CV]0 were optimized of both Fenton and photo-Fenton processes for the removal of CV dye from aqueous media. Kinetic results indicated that photo-Fenton process (k obs=0.0097 min−1, t 1/2=71.45 min) is more effective than Fenton process (k obs=0.0074 min−1, t 1/2=93.66 min). Second order rate constant of ˙OH radical with CV dye was calculated to be 3.96×109 M−1s−1. De-methylated organic intermediates of CV dye detected by LC-MS and some other intermediates like CH3COO−, HCOO−, NH4 + and Cl− were identified by ion-chromatography.

Multi‐walled carbon nanotubes supported amorphous Fe2O3 and Ag2O–Fe2O3 as Fenton catalysts for degradation of maxilon red dye

AbstractTwo Fenton‐like catalysts of iron oxide (Fe2O3) or Fe2O3 doped with silver oxide (Ag2O) and supported on acidified multi‐walled carbon nanotubes (a‐MWCNTs) were successfully prepared by wet impregnation and calcined at 200 °C and noted as Fe2O3/MWCNTs and Ag2O‐Fe2O3/MWCNTs, respectively. These samples were characterized using techniques such as TEM, FTIR, N2 adsorption at ‐196 °C, and XRD. Their catalytic performances were determined through Fenton oxidation process of maxilon red dye (MR) at 25 °C. Fenton degradation results disclosed that the Ag2O‐Fe2O3/MWCNTs nanocomposite has the superior and the faster catalytic degradation rate of dye. This result was due to the synergistic effect that established from the combination of tiny amount of Ag2O with Fe2O3 over a‐MWCNTs support, which prevents the agglomeration of catalyst nanoparticles and enhances the adsorption of dye molecules. A full degradation of dye was obtained within 10 min at 25 °C and the Fenton oxidation capability of Fe2O3/MWCNTs catalyst increased by about 10% after loading ~1wt.% of Ag2O. The catalytic performance was considerably based on pH of solution, H2O2 concentration, and dye concentration. The reusability tests confirmed that Ag2O‐Fe2O3/MWCNTs nanocomposite offers high stability over three consecutive cycles, where over 90% degradation of MR dye was obtained. Finally, Ag2O‐Fe2O3/MWCNTs nanocomposite showed excellent Fenton catalytic oxidation and reusability as compared with Fe2O3/MWCNTs composite in Fenton‐like processes.

Assessment of carbon monoxide formation in Fenton oxidation process: The critical role of pollutant nature and operating conditions

This work assesses the carbon monoxide formation upon Fenton process, the most popular method for Advanced Oxidation Processes (AOPs). CO concentrations in the order of 11,000 mg/Nm3 were measured in the Fenton oxidation of phenol after 180 min reaction at 90 °C and 3 bar. The Fenton oxidation performed on phenol and its oxidized intermediates such as hydroquinone, catechol and short-chain acids allows concluding that CO is produced through the oxidative cleavage of aromatic rings; the hydroquinone route being more selective to CO than catechol. In all cases, the carbon mass balance was satisfactorily closed to 100%. The study of the influence of the operational conditions shows that CO production is clearly favoured at H2O2 dosage above the stoichiometric value and low temperatures (T < 90°). The H2O2 dosage was the most influence variable.The results of this work evidence for the first time the production of noxious amounts of CO along with CO2 in Fenton processes. This finding highlights the importance of evaluating not only liquid phase intermediates due to their recalcitrant and/or toxic behavior, but also gas phase because of CO emissions.

Fe–Mn/MCM-41: Preparation, Characterization, and Catalytic Activity for Methyl Orange in the Process of Heterogeneous Fenton Reaction

Active Fe- and Mn-loaded MCM-41 (Fe–Mn/MCM-41), which was synthesized via a hydrothermal reaction followed by impregnation, is used in the heterogeneous Fenton reaction to degrade methyl orange (MO) in aqueous solution. The synthesized samples were characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscopy, N2 adsorption–desorption isotherm analysis, Fourier transform infrared spectroscopy, and X-ray photoelectron spectroscopy. Compared with Fe/MCM-41 and Mn/MCM-41, Fe–Mn/MCM-41 showed higher activity for MO degradation and mineralization. Effects of various operating parameters, such as pH, Mn content, and H2O2 dosage, on the degradation process were subsequently investigated. Results of experiments on the effect of radical scavengers revealed that the degradation of MO could be attributed to oxidation by HO·. The synergy of Fe and Mn species in the Fenton oxidation process was also explained.

Removal of Acid Yellow 17 Dye by Fenton Oxidation Process

Abstract In the present research work the degradation of acid yellow 17 (AY 17) by H2O2/Fe2+ was investigated. The effect of various conditions such as pH value, temperature, conc. of H2O2, Fe2+, conc. of AY 17 were studied. Additionally the scavenging effects of various anions such as Cl−, SO4 2−, CO3 2− and HCO3 −, on percent degradation of AY 17 were examined. It was found that these anions decrease percent degradation as well as rate of degradation reaction. The optimum conditions were determined as [AY 17]=[Fe2+]=0.06 mM [H2O2]=0.9 mM, and pH 3.0 for 60 min of reaction time. It was found that at optimum conditions 89% degradation of AY17 was achieved. The degradation kinetics of AY17 followed pseudo-first-order reaction kinetics. Thermodynamic studies under natural conditions showed positive value of ∆H (enthalpy) which indicates the degradation process is endothermic.

Study on the degradation mechanism and pathway of benzene dye intermediate 4-methoxy-2-nitroaniline via multiple methods in Fenton oxidation process.

Benzene dye intermediate (BDI) 4-methoxy-2-nitroaniline (4M2NA) wastewater has caused significant environmental concern due to its strong toxicity and potential carcinogenic effects. Reports concerning the degradation of 4M2NA by advanced oxidation process are limited. In this study, 4M2NA degradation by Fenton oxidation has been studied to obtain more insights into the reaction mechanism involved in the oxidation of 4M2NA. Results showed that when the 4M2NA (100 mg L−1) was completely decomposed, the TOC removal efficiency was only 30.70–31.54%, suggesting that some by-products highly recalcitrant to the Fenton oxidation were produced. UV-Vis spectra analysis based on Gauss peak fitting, HPLC analysis combined with two-dimensional correlation spectroscopy and GC-MS detection were carried out to clarify the degradation mechanism and pathway of 4M2NA. A total of nineteen reaction intermediates were identified and two possible degradation pathways were illustrated. Theoretical TOC calculated based on the concentration of oxalic acid, acetic acid, formic acid, and 4M2NA in the degradation process was nearly 94.41–97.11% of the measured TOC, indicating that the oxalic acid, acetic acid and formic acid were the main products. Finally, the predominant degradation pathway was proposed. These results could provide significant information to better understand the degradation mechanism of 4M2NA.

Experimental and mathematical modelling of reactive dyes decolorization using Fenton oxidation process in a microfluidic system

Experimental and mathematical modelling of reactive dyes decolorization using Fenton oxidation process in a microfluidic system

Use of laterite as a sustainable catalyst for removal of fluoroquinolone antibiotics from contaminated water

Although there is a growing interest in Fenton oxidation processes based on natural catalysts, the use of laterite soil to promote sequential adsorption/oxidation treatments of fluoroquinolone antibiotics has been scarcely investigated. In this work, the ability of an african laterite containing goethite and hematite to remove flumequine (FLU), used as a representative compound of fluoroquinolone antibiotics, was evaluated under dark and UVA irradiation. Batch experiments and liquid chromatography analyses showed that the presence of laterite can enhance FLU removal from heavily contaminated water through both sorption and oxidation reactions (up to 94% removal of 77 μmol L−1 of FLU and 72% of mineralization). The heterogeneous reaction rate is dominated by the rate of intrinsic surface chemical reactions including sorption and oxidation of FLU, and light-induced reduction of FeIII sites to produce FeII. Based on the probe and scavenging experiments, OH radicals were mainly involved in the heterogeneous oxidation reaction. The photo-assisted Fenton process showed a high efficiency of FLU removal even in the presence of a second fluoroquinolone antibiotic, norfloxacin (NOR), which can be co-found with FLU in affected environments. Determinations of kinetic rate constants and total organic carbon (TOC) for five sequential adsorption/oxidation cycles showed that laterite exhibited no deactivation of surface sites and an excellent catalytic stability. This cost-effective and environmentally friendly remediation technology may appear as a promising way for the removal of fluoroquinolone antibiotics from multi-contaminated waters.

Techno-economical assessment of coupling Fenton/biological processes for the treatment of a pharmaceutical wastewater

A wastewater coming from a pharmaceutical plant of chemical organic synthesis with a TOC of ca 1.4 g/L and low biodegradability has been treated by coupling of advanced Fenton oxidation process and subsequent biological treatment. The influence of the reaction temperature, the hydrogen peroxide concentration and the iron/copper loadings as catalysts in the Fenton process were studied. A moderate oxidant concentration (7.5 mgH2O2/mgTOC) and a temperature of 70 °C enhanced the biodegradability of the wastewater with a TOC reduction of ca. 35%. A subsequent biological treatment operating with HRT and SRT of 2 days and 20 days, respectively, allowed increasing the TOC removal above 90%. The oxidant concentration and the reaction temperature of Fenton process as pre-treatment to increase biodegradability were significantly lower than the values of the Fenton process currently implemented in the pharmaceutical plant to achieve an almost complete mineralization of the organic matter (21.4 mgH2O2/mgTOC and 120 °C, respectively). The techno-economical evaluation of the coupling Fenton/biological system compared to the Fenton process as unique treatment, showed that the lower oxidant uptake of the Fenton process for the coupling system is economically more profitable than using an excess of oxidant and a higher reaction temperature for the intensive Fenton process.

Degradation of chlordecone and beta-hexachlorocyclohexane by photolysis, (photo-)fenton oxidation and ozonation

ABSTRACTIntensive use of chlorinated pesticides from the 1960s to the 1990s has resulted in a diffuse contamination of soils and surface waters in the banana-producing areas of the French West Indies. The purpose of this research was, for the first time, to examine the degradation of two of these persistent pollutants – chlordecone (CLD) and beta-hexachlorocyclohexane (β-HCH) in 1 mg L−1 synthetic aqueous solutions by means of photolysis, (photo-) Fenton oxidation and ozonation processes. Fenton oxidation is not efficient for CLD and yields less than 15% reduction of β-HCH concentration in 5 h. Conversely, both molecules can be quantitatively converted under UV-Vis irradiation reaching 100% of degradation in 5 h, while combination with hydrogen peroxide and ferrous iron does not show any significant improvement except in high wavelength range (>280 nm). Ozonation exhibits comparable but lower degradation rates than UV processes. Preliminary identification of degradation products indicated that hydrochlordecone was formed during photo-Fenton oxidation of CLD, while for β-HCH the major product peak exhibited C3H3Cl2 as most abundant fragment.

Degradation of the Antibiotic Ceftriaxone by Fenton Oxidation Process and Compound Analysis

Degradation of the Antibiotic Ceftriaxone by Fenton Oxidation Process and Compound Analysis

Synthetic olive mill wastewater treatment by Fenton's process in batch and continuous reactors operation.

Degradation of total phenol (TPh) and organic matter, (expressed as total organic carbon TOC), of a simulated olive mill wastewater was evaluated by the Fenton oxidation process under batch and continuous mode conditions. A mixture of six phenolic acids usually found in these agro-industrial wastewaters was used for this purpose. The study focused on the optimization of key operational parameters of the Fenton process in a batch reactor, namely Fe2+ dosage, hydrogen peroxide concentration, pH, and reaction temperature. On the assessment of the process efficiency, >99% of TPh and >56% of TOC removal were attained when [Fe2+]=100ppm, [H2O2]=2.0g/L, T=30°C, and initial pH=5.0, after 300min of reaction. Under those operational conditions, experiments on a continuous stirred-tank reactor (CSTR) were performed for different space-time values (τ). TOC and TPh removals of 47.5 and 96.9%, respectively, were reached at steady-state (for τ=120min). High removal of COD (>75%) and BOD5 (>70%) was achieved for both batch and CSTR optimum conditions; analysis of the BOD5/COD ratio also revealed an increase in the effluent's biodegradability. Despite the high removal of lumped parameters, the treated effluent did not met the Portuguese legal limits for direct discharge of wastewaters into water bodies, which indicates that coupled chemical-biological process may be the best solution for real olive mill wastewater treatment.

Heterogeneous nZVI-induced Fenton oxidation process to enhance biodegradability of excavation by-products

The treatment of excavation by-products has been studied using Fenton and Heterogeneous Fenton processes, by the addition of zero-valent iron nanoparticles (nZVI) as catalyzer. This study demonstrated that both methods could significantly reduce the organic content of the liquid extract from excavated soils. Operating parameters, such as pH and catalyzer/oxidant (w/w) ratio, were varied to investigate their influence on the Total Organic Carbon (TOC) and Chemical Oxygen Demand (COD) removal efficiency. In addition, Biochemical Oxygen Demand (BOD) was evaluated before and after the treatment. The optimal conditions found for conventional Fenton process were: H2O2/COD = 1 (w/w), Fe(II)/H2O2 = 0.1 (w/w) and pH = 2.5, whereas for Heterogeneous Fenton were: H2O2/COD = 0.75 (w/w), nZVI/H2O2 = 1.5 (w/w) and pH = 3. Heterogeneous Fenton resulted more efficient with respect to conventional Fenton, leading to a TOC and COD removal efficiency equal to 75.95 and 85.52%, respectively. The BOD28/COD ratio after Heterogeneous Fenton increased by about 200%, indicating the suitability of this oxidation process to achieve a biodegradability increase.