Fenton Process Research Articles

Using the Fenton reactions to eliminate Total Organic Carbon (TOC) from industrial effluents

Industrial effluents are produced in large quantities in underdeveloped nations, where they cannot be handled using conventional treatment techniques. In this study, hydroxyl radicals (HO•) were successfully generated for the treatment of industrial wastewater represented in TOC removals by combining aferrouscatalystwithhydrogenperoxidein the Fenton reaction. The effects of operating conditions of pH, ferrous dose, H2O2 dose, time, and initial TOC concentration were studied for the Fenton process and different operating parameters were studied for the coagulation process to optimize and control the removal efficiency. The results showed that Fenton oxidation processes are able to reduce about 86 % for initial TOC level of 2000 and 95 % for initial TOC level of 400 after using 0.15 g/L ferrous dose, 10 mL/L of 30 % H2O2 for 30 min at acidic pH 4. Finally, this study recommends removing organic materials from industrial effluent using the Fenton oxidation method.

Synergistic photogeneration of reactive oxygen species by Fe species self-deposited on resorcinol-formaldehyde towards the degradation of phenols under visible light

In this study, a heterogeneous photo-Fenton catalyst of Fe species/resorcinol-formaldehyde (Fe/RF) was synthesized in the degradation process of phenols under visible light in a homogeneous photo-Fenton system. The in situ generated H2O2 by bare RF in the medium and the follow-added Fe2+ can construct homogeneous photo-Fenton system, and Fe/RF heterogeneous photo-Fenton catalyst was formed after the reaction through Fe species self-deposition. Due to the addition of Fe2+, more hydroxyl radical (·OH) generated in the homogeneous Fenton system, which lead to the higher degradation efficiency of phenols that achieved 90.5 % with 150 min. Fe/RF was subsequently formed and more C=O functional group in the structure appeared, which was beneficial to the production of H2O2. The above-mentioned results can be proved by the involved calculation and experimental results. Fe species, including Fe2+ and Fe3+, were beneficial to the conversion of reactive oxygen species (ROSs), and further improved the degradation efficiency of Phenols. Since the existence of photo-generated electrons, Fe2+ concentration in the solution can maintain a stable level. Interestingly, the degradation efficiency of Phenols was higher when Fe3+ was used instead of Fe2+ as the additive, which may be caused by the promotive effect of Fe3+ on singlet oxygen (1O2) generation. In addition, the degradation efficiency of Phenols under alkaline conditions was higher than that under acid conditions, which broke the limit of traditional Fenton process that works mostly in acidic medium. This study shows promising results in terms of synergistic photocatalytic/photo-Fenton processes for the degradation of organic pollutants in water.

The impact of rainwater-borne H2O2-induced Fenton process on root iron plaque formation and arsenic accumulation in rice

Arsenic (As) contamination is a global concern, especially in paddy fields, as it represents a significant pathway for As reaching in the food chain. This is primarily due to the high accumulation of As in rice grains, which is a staple food for billions of people globally. Here we investigated the effect of synthetic rainwater-borne hydrogen peroxide (H2O2)-induced Fenton oxidation process in paddy soil on As uptake and speciation in rice plants at different growth stages. Results showed that adding Fenton reagents significantly accelerated root iron (Fe) plaque formation, thereby enhancing As retention in soil. Arsenic accumulation in different rice plant parts followed the order: Fe plaque > root > stem > leaf. In rice grains, inorganic As and dimethylarsinic acid (DMA) were the major As species for the first and second-season crops. Notably, that the addition of Fenton reagents to paddy soil led to a significant reduction in As accumulation in rice grains. The synthetic rainwater-borne H2O2-induced Fenton reaction significantly promoted As(V) precipitation and decreased concentration of the dissolved As in soil porewater. The current study highlights that the H2O2-induced Fenton process is an important pathway decreasing As bioavailability in paddy soil and its accumulation in rice grain. The findings have implications for understanding As behavior in paddy fields receiving rainwater-borne H2O2 and for developing cost-effective remediation programs to reduce As accumulation in rice grains.

Electrocoagulation Coupled Fenton Process for Treating Refinery Wastewater Using a Cylindrical Design of Ti and Al Electrodes

Due to the serious wizards that industrial waste causes to humans, animals, and plants, besides the fact that wastewater from refineries contains many harmful compounds and that this type of industry is prevalent in most countries, the issue of protecting the environment from industrial waste is importance at the recent time. The organic contaminants elimination from the wastewater connected with the Iraqi refinery at Qayyarah served as our case study. The chemical oxygen demand (COD) was the organic contaminants measure. A titanium electrode (cathode) and an aluminum electrode (anode) were combined with the electrocoagulation and Photo-Fenton-processes. Using a Mini Tab program, the Taguchi method Utilizing statistical techniques, successfully obtained the outcomes and final values. The most effective removal of COD was 90.148. With a standard deviation of 2.651, the best conditions for this experiment were as follows: The time required to achieve this removal efficiency was 50 minutes, 8 pH, 400 mg/L of hydrogen peroxide, 20 mg/L of ferrous sulfate, and a current density of 15 mA cm-2. Through ANOVA analysis of this process, it was found that the current density (C.D.) significantly influenced the removal efficiency, affecting it by 47.79%, followed by the electrolytic solution effect by 18.31%, and the hydrogen peroxide and ferrous sulfate concentrations effect by 12.55% and 2.36%, respectively. Also, a mathematical equation was found to describe the studied case. The reaction kinetics were also investigated, and the reaction rate constant (cm/s) was determined at ideal conditions, with km = 6.60546 x 10-5.

Enhanced photodegradation of 3-nitro-1, 2, 4-triazol-5-one by FeCuO bimetallic catalyst supported on mesoporous carbon nitride

3-Nitro-1,2,4-triazol-5-one (NTO) is one high energy and insensitive single explosive that has been applied in insensitive ammunition in recent years. However, the high deposition of NTO after detonation and the challenge of wasterwater treatment during its productive process are the key concerns of the environmental issue and safe manufacture. The catalytic performance of the traditional Fe-based catalysts for the decontaminating wastewater owing to the high stability of the triazole ring of NTO. To address this problem, FeCuO/mpg-C3N4 was prepared by depositing Fe-Cu oxides on mesoporous carbon nitride (mpg-C3N4) as the catalysts of photo Fenton process. After optimizing the metal ratio and screening the reaction condition, FeCuO/mpg-C3N4(5:5, 6%) exhibited the unprecedent k value of 0.10669 min−1 (96.4% degradation after 30 min) in the photo degradation of NTO (λ > 400 nm; 1000 mg/L FeCuO/mpg-C3N4; 40 mg/L NTO) and maintained high catalytic activity after 2 cycles (k1 =0.09491 min−1, k2 =0.08607 min−1). By characterizing thoroughly the catalysts, the synergetic effect of Fe-Cu bimetallic oxide and the contribution of the carbon nitride in the photo Fenton process have been evidenced, which presents an efficient, environmentally friendly, and cost-effective approach for treating NTO wastewater, offering a novel method and concept for addressing other challenging-to-degrade organic pollutant wastewaters.

Optimization of Fe(II)/SPC Sludge Conditioning and Dewatering Process Based on Response Surface Methodology: Full-Scale Application

Sludge conditioning is a crucial step in sludge dewatering aimed at minimizing excessive sludge production. The Fenton process, which harnesses oxidative radicals to dismantle extracellular polymeric substances (EPS) and microorganisms, has been unequivocally proven to enhance sludge dewaterability. However, the widespread adoption of the Fenton process is hampered by its high costs and logistical challenges in transportation. In contrast, the Fe(II)-activated sodium percarbonate (Fe(II)/SPC) process has emerged as a promising technology for sludge conditioning due to its remarkable performance and safe operation. However, limited information is available regarding the optimization of Fe(II)/SPC for sludge conditioning and dewatering at full scale. This study conducted the sludge conditioning and dewatering process within a full-scale wastewater treatment plant, utilizing the response surface methodology (RSM) to optimize the Fe(II)/SPC process. Furthermore, this study investigated its impact on sludge structure and compared the economic benefits of the Fe(II)/SPC process with other full-scale conditioning processes. The results of bound water and LDH analysis revealed that the Fe(II)/SPC process not only degraded EPS but also disrupted microbial cells, thereby releasing intracellular water. Based on the RSM results, we successfully established a polynomial prediction model to determine the optimal capillary suction time (CST) and moisture content. The optimal parameters determined through RSM were an initial pH of 3.02, Fe(II) dosage of 0.05 g/g TSS, and SPC dosage of 0.07 g/g TSS. The validation test confirmed the accuracy of the prediction results, with the conditioned sludge exhibiting a CST of 31.6 s and a moisture content of 51.47%. Furthermore, when compared to the PFS and Fenton processes, the Fe(II)/SPC process demonstrated higher economic efficiency and safety, while maintaining good dewatering performance. Overall, the Fe(II)/SPC treatment shows promise as a prospective sludge dewatering and conditioning process.

Humic acids as complexing agents to drive photo-Fenton at mild pH in saline matrices: Process performance and mechanistic studies

The role of iron complexation on (photo)-Fenton process at mild pH has been investigated; in particular, the effect of humic acids, their interaction with chlorides and the involvement of the target pollutants has been studied. For this purpose, solutions consisting in mixture of 6 pollutants (acetaminophen, acetamiprid, amoxicillin, caffeine, carbamazepine and clofibric acid) in different matrices ( a) distilled water, b) low salinity water (1 g·L−1 of Cl-), c) high salinity water (30 g·L−1 of Cl-), d) tap water and e) real sea water) have been irradiated with simulated sunlight with and without humic acids (10 mg L−1). The ability of humic acids to complex Fe(III) resulted in an enhancement of pollutants removal as prevented iron inactivation, but in highly saline waters were they were not able to displace completely Cl- as ligands for Fe(III) and in sea water where other species could also contribute to inhibit photo-Fenton. Furthermore, pollutants with phenolic and/or carboxylic moieties also contribute to keep iron active at pH = 5, most probably by complexation. This is in line with dissolved iron at the end of the experiment and hydrogen peroxide consumption. Electron spin resonance measurements of ·OH show a very good correlation between the radical formation and pollutants removal, indicating that in the presence of complexing agents, generation of ·OH is favoured. These results indicate that HA could be used as auxiliary to apply photo-Fenton in low salinity environments rather than in real seawater.

An experimental investigation of textile dyeing wastewater using modified electro Fenton process with optimization by response surface methodology

AbstractElectro‐Fenton oxidation may improve wastewater biocompatibility. In this investigation, steel flakes were used as a novel catalyst in the Enhanced Electro Fenton procedure, in place of the traditional Electro Fenton Process. A degradation study of textile dyeing effluent has been conducted using the Modified Electro Fenton process. In 60 min of reaction time in the Electro‐Fenton process, 98.57%, 95.38%, and 94.93% of color removal was achieved for reactive blue, reactive yellow, and reactive black dyes respectively. From the Laboratory‐scale feasibility studies on the Electro‐Fenton process, the utmost color and COD elimination efficiency of 93% and 70% correspondingly observed at a catalyst dosage of 1 g/L, H2O2 dosage of 132 mM at pH 3. In this study, the average coefficient of correlation was 0.9978, indicating that the framework could describe 99.78% of the variability in response. The Analysis of variance (ANOVA) of the quadratic regression analysis shows that the model is incredibly substantial, as displayed by the Fisher F‐test (F model = 347.52) with the lowest probability value (p model > F = 0.0001). The predicted results from Response Surface Methodology (RSM) closely agreed with the experimental results obtained during the optimization studies and hence confirmed the results obtained.

Cobalt Ferrite (CoFe2O4) Spinel as a New Efficient Magnetic Heterogeneous Fenton-like Catalyst for Wastewater Treatment

For the first time, cobalt ferrite spinel (CoFe2O4) was used as a catalyst in the Fenton process for Remazol Red RR dye degradation in water. CoFe2O4 was synthesized via gel combustion using tris(hydroxymethyl)aminomethane as an alternative fuel in one step with a ratio of Ψ = 0.8. Its structural, surface optics, magnetic properties, and the optimal conditions of the Fenton reagents for dye degradation were evaluated. The saturation magnetization and remanence (Ms and Mr, respectively) for the as-prepared powder were 65.7 emu/g and 30.4 emu/g, respectively, and the coercivity (Hc) was 1243 Oe, indicating its ferromagnetic nature and suitability as a magnetic catalyst. Red Remazol RR dye degradation tests were performed using the Fenton process to evaluate the influence of the catalyst dosage and H2O2 concentration. The tests were performed in a batch reactor in the dark with constant agitation for 24 h. The best result was obtained using 1 g/L of catalyst with a dye degradation of 80.6%. The optimal concentration of H2O2 (1.0 M) resulted in 96.5% dye degradation. Nanoparticle recyclability testing indicated that the material could be satisfactorily reused as a catalyst for at least three cycles. The potential use of the CoFe2O4 synthesized in this study as a catalyst for dye degradation by the Fenton process was demonstrated.

Depth Treatment of Engineering Applications Wastewater Using a Sequential Heterogeneous Fenton and Biodegradation Approach: Review

After treating industrial wastewater efficiently and adequately to avoid harm from it being reused and disposed of in the past, the majority of countries in the world have moved to integrated planning and sound management to reuse it. The efficiency of water treatment and reuse depends on a set of environmental standards and controls that are connected to the nature of this water and the eventual purpose of treating and reusing it in order to prevent the environmental repercussions of an integrated method. A framework that assures environmental protection must be employed for this treatment and reuse. The emphasis is on developing reusable resources in order to transition from a linear to a circular economy. Finding the primary pathway for heterogeneous and homogeneous catalysis to pollutant degradation, optimizing the layout for integrating Fenton processes into large-scale treatment plants, particularly its coupling with biological treatment, and analyzing or enhancing heterogeneous catalyst lifetime are all important. are some of the main challenges mentioned in this research. This study intends to analyze the efficacy of the Fenton process in treating water in an effective and economical way compared to other conventional techniques.

Towards removal of PPCPs by advanced oxidation processes: A review

The continuous influx of emerging contaminants (ECs) into water bodies poses a significant threat to human health. Among these contaminants, pharmaceuticals and personal care products (PPCPs) are of particular concern due to their potential to exert adverse effects even at low concentrations. Therefore, it is imperative to explore methods for their effective removal or reduction to safeguard both human health and the ecological environment. Advanced oxidation processes (AOPs) have received substantial attention as promising treatment methods. AOPs are capable of efficiently treating water by generating reactive oxygen species (ROS) with potent oxidation properties, which can effectively eliminate various contaminants. This review delves into the diverse range of AOPs available, including ozonation, photocatalytic oxidation, the Fenton process, electrochemical oxidation, sulfate radicals-based advanced oxidation processes (SR-AOPs), and more. It also discusses the respective limitations and future prospects of these processes, aiming to provide insights into their potential for addressing the pressing issue of PPCP contamination in water bodies.

Enhanced Fenton-like oxidation (Vis/Fe(III)/Peroxydisulfate): The role of iron species and the Fe(III)-LVF complex in levofloxacin degradation

Traditional Fenton and Fenton-like processes are affected by the sluggish kinetics of Fe(II) regeneration and Fe(III) accumulation. This research revealed that the degradation efficiency of pollutants was significantly increased by adding Fe(III) to the Vis/PS system. A mechanism is proposed in which photosensitivity pollutants can boost Fe(III) to produce Fe(II) under visible light irradiation. Intriguingly, Fe(III) rapidly combines with LVF in aqueous environments to form Fe(III)-LVF complexes. This research confirms that Fe(III)-pollutant complexes are generated. The proportion of complexes are calculated using mathematical models. Furthermore, the production of Fe(IV) is verified in the Vis/PS/Fe(III) system, which also plays a vital role in boosting LVF degradation. Overall, this study provides comprehensive insights into the degradation mechanism of micropollutants, involving hydroxyl radical (OH∙), Fe(IV), and Fe(III)-LVF complexes, providing an efficient and green strategy for contaminant removal during wastewater treatment.

Sustainable developmental measures for the treatment of pharmaceutical industry effluent using nano zero valent iron technology (nZVI) – A review

Among the diverse nanomaterials, nanoscale zero-valent iron (nZVI) particle is one of the superior materials used for the condition of remediation and environmental restoration. As a result of the nanoscale dimension of nZVI particles and its relatively high surface, it is capable of undergoing various chemical reactions, including reduction, oxidation and adsorption of toxic metals, inorganic substances and organic compounds. In the pharmaceutical industry, mass production of drugs results in the widespread dumping of effluents. As emerging pollutants, antibiotics are non-biodegradable compounds that have potential to adversely affect human genetic and hormonal systems posing a risk to human health and the environment. Global health is endangered by antibiotics present in surface waters and drinking water. Drug contaminants can be removed using a synergistic process involving various advanced methods, including ozonation, fenton process, photocatalytic degradation, reverse osmosis and, adsorption techniques. The enhancement of nZVI composites and earlier studies were reviewed, as well as the evaluation of zero valent iron nanoparticles' effectiveness in eliminating antibiotic effluents from water bodies. This review also revealed the various methods of the determination of toxicity associated with nZVI treated pharmaceutical effluents. The present study would suggest the possible utilization of nZVI technology for the effective removal of hazardous pharmaceutical contaminants through sustainable green measures.

Relay run property of immobilized cholesterol oxidase on magnetic biochar for sterol removal

This study investigated the biocatalytic performance of immobilized cholesterol oxidase (CHOD) on magnetite-based carbon (MBC) for degrading cholesterol. The results showed that MBC-CHOD exhibited higher activity and good affinity towards substrate compared to free enzyme and other immobilized enzymes. Mass spectra analysis revealed that MBC-CHOD damaged the main structure of cholesterol, benefitting the further biological treatment. The study proposes a Fenton process mechanism by which H2O2 is transferred to free radicals such as ·OH under acidic conditions, promoting further substrate degradation. This suggests that MBC-CHOD has a relay run property leading to high degradation of cholesterol. Molecular docking indicates that cholesterol preferentially binds to TYR-28 residue and LYS-138 residue in CHOD through hydrogen bonds. Overall, MBC-CHOD proved to be a promising candidate for efficient and sustainable cholesterol degradation.

A sustainable and cyclic metal organic framework-driven Fenton process for efficient removal of methylene blue

A sustainable and cyclic metal organic framework-driven Fenton process for efficient removal of methylene blue

Degradation of imidacloprid via the activation of peroxymonosulfate and peroxydisulfate using a Fenton-sludge-derived Fe0/Fe3C composite

The Fenton process is a commonly employed advanced oxidation process for industrial wastewater treatment. However, large volumes of iron-containing sludge are generated in the Fenton reaction, causing secondary pollution. In the present study, we report a Fenton-sludge-derived biochar (FSB) designed to degrade the neonicotinoid pesticide, imidacloprid (IMD) via activation of peroxymonosulfate (PMS) and peroxydisulfate (PDS). The effect of pyrolysis temperature on the transformation of the crystal phase and surface functional groups of samples was monitored using X-ray diffraction, Fourier transformation-infrared spectroscopy, and scanning electron microscopy. The use of FSB treated at 900 °C (FSB 900) containing the iron phase Fe0/Fe3C led to the highest IMD degradation efficiency with both PMS and PDS (92.7 ± 0.5 % and 100.0 ± 0.0 %, respectively; [IMD]0 = 20 mg/L, [persulfate]0 = 2 mM, [FSB]0 = 0.2 g/L, reaction time = 60 min). The main reactive species involved in IMD degradation via PMS and PDS activation using FSB 900 were identified with scavenger tests. The effects of solution pH and the additional anions on the performance of IMD removal efficiency were also investigated. This study provides insights into the recycling of solid waste derived from the Fenton process and the degradation of recalcitrant organic pollutants in wastewater.

Degradation of pesticides by heterogeneous Fenton using iron-exchanged clays

The aim of this research is to study the feasibility of using low-cost and natural bentonite and kaolinite clays, compared with commercial bentonite, as raw materials to prepare catalysts for the removal of two emerging pollutants, the neonicotinoid pesticides nitenpyram and acetamiprid, by heterogeneous Fenton process. The raw materials were subjected to a simple ion exchange method to improve their textural properties using a solution containing ferric cations followed by calcination at 500 °C. Results show high activity for all the catalysts in the removal of these pesticides, Stability tests were carried out confirming the high stability of these materials.

Facile synthesis of excellent Fe3O4@starch-derived carbon Photo-Fenton catalyst for tetracycline degradation: Rapid Fe3+/Fe2+ circulation under visible light condition

Photoinduction is widely used to accelerate the Fe3+/Fe2+ circulation in Fe3+/H2O2 Fenton oxidation, however, the remained challenges in developing a facile, economical, and efficient synthetic methodology for the preparation of high-performance Fe-based Photo-Fenton catalyst and inevitably forming iron sludge limit its applications. Herein, starch-derived carbon (SC) encapsulated Fe3O4 (Fe3O4@SC) magnetic nanocomposites are synthesized by mechanical activation treatment combined with high-temperature pyrolysis method using cassava starch as the carbon source. The photoelectrochemical properties of Fe3O4@SC are regulated by COFe bonds and oxygen vacancies in Fe3O4@SC, as well as graphitization of SC, which effectively accelerate the Fe3+/Fe2+ circulation in Fe3O4@SC + H2O2 system under visible light, thus Fe3O4@SC shows excellent catalytic performance and superior stability for the degradation of tetracycline hydrochloride, and the initiation rate constant is 2.4 times higher than that in dark. Moreover, quenching experiments and electron spin resonance results confirm that OH, O2−, and h+ (OH plays a critical role) are generated in the catalytic system of Fe3O4@SC + H2O2 + visible light. This work provides new insights into a green and facile approach for the synthesis of Photo-Fenton catalysts, providing new avenue for the acceleration of Fe3+/Fe2+ cycle under visible light-driven Fenton process.

Fenton-like process evaluation of textile effluent discolouration using pyrite tailings: Influence of dissolved iron

This study investigated the discoloration of real textile effluents using raw pyritic waste (RPW) as a Fenton-like process catalyst, as well as the influence of particle size and pre-treatment with distilled water only. The RPW was collected from a waste pile, following the ABNT NBR 10007:2004 standard, and ground to obtain particles with an average diameter of 0.75 and 1.5 mm. RPW and Washed Pyritic Waste (WPW) samples were characterized by XRF, FTIR and XRD. The operational conditions were assessed from an experimental design, varying the catalyst concentrations, H2O2 and the reaction time. XRD results showed the majority presence of FeS2 in the samples and the pre-treatment removed impurities, such as quartz and soluble compounds, from the catalyst surface. The experimental design determined that the 0.75 mm size was more efficient in removing colour from the effluent. The optimal condition was defined as 2 g/L of catalyst, 2 g/L of H2O2 and 2 h. The effluent colour degradation capacity was greater than 90% for RPW and WPW samples. However, WPW released less iron into the resulting solution (10.51 mg/L). The catalyst proved to be stable for sequential use and after five cycles, the discoloration rate was greater than 80%. Root growth was verified for the Allium cepa test using the post-treatment and neutralized effluent. The results indicate a potential use of pyritic wastes from coal mining as catalysts for the Fenton process for real textile effluents discoloration, adding environmentally friendly value to a material considered an environmental liability.

Carbon-neutral potential in treatment of N, N-dimethylformamide-containing industrial wastewater: Comparative investigation of energy conservation, carbon reduction and expenditure between UASB and Fenton process

The methanogenic degradation of N, N-dimethylformamide (DMF) is a sustainable and low-carbon technology for the treatment of high-strength industrial wastewater. Compared with the state-of-the-art chemical degradation method like Fenton, the UASB process exhibited its promising superiority in bio-energy recovery, economic profit gaining and carbon emission reduction. The lab-scale UASB obtained high DMF removal efficiency of over 98 % with methane recovered as bio-energy at a limited organic loading rate (OLR) of 4.2 COD kg/m3/d. Compared with the Fenton process, the UASB process is demonstrated more suitable to the carbon-neutral treatment of high-strength DMF-containing wastewater: The Fenton process is suitable to the relative low COD concentration below 1500 mg/L; The UASB was capable of covering all electricity consumption when COD > 3586 mg/L; The UASB also achieved zero CO2 emission when COD > 5720 mg/L; The UASB process obtains net profit when COD > 3616 mg/L. This study provided clear evidence of the promising potential and remarkable feasibility of bio-energy production in carbon-neutral treatment of DMF-containing wastewater.