Fenton Catalyst Research Articles

Multifunctional Nanoparticles for Enhanced Chemodynamic/Photodynamic Therapy through a Photothermal, H2O2-Elevation, and GSH-Consumption Strategy.

Chemodynamic therapy (CDT) has witnessed significant advancements in recent years due to its specific properties. Its association with photodynamic therapy (PDT) has also garnered increased attention due to its mutually reinforcing effects. However, achieving further enhancement of the CDT/PDT efficacy remains a major challenge. In this study, we have developed an integrated nanosystem comprising a Fenton catalyst and multifunctional photosensitizers to achieve triply enhanced CDT/PDT through photothermal effects, H2O2 elevation, and GSH consumption. We prepared nano-ZIF-8 vesicles as carriers to encapsulate ferrocene-(phenylboronic acid pinacol ester) conjugates (Fc-BE) and photosensitizers IR825. Subsequently, cinnamaldehyde-modified hyaluronic acid (HA-CA) was coated onto ZIF-8 through metal coordination interactions, resulting in the formation of active targeting nanoparticles (NPs@Fc-BE&IR825). Upon cellular internalization mediated by CD44 receptors, HA-CA elevated H2O2 levels, while released Fc-BE consumed GSH and catalyzed H2O2 to generate highly cytotoxic hydroxyl radicals (·OH). Furthermore, NIR irradiation led to increased ·OH production and the generation of singlet oxygen (1O2), accompanied by a greater GSH consumption. This accelerated and strengthened amplification of oxidative stress can be harnessed to develop highly effective CDT/PDT nanoagents.

Iron ore tailings as efficient Fenton-like catalysts for degradation of tetracycline

Antibiotic wastewater, especially that generated from hospital and pharmaceutical industries, is highly concentrated, hazardous and in urgent need of treatment. This work explores the possibility of directly using iron ore tailings (IOT), a typical solid waste, as a Fenton catalyst for the removal of antibiotics from water. Take tetracycline hydrochloride (TC-HCl) as the target antibiotic, the degradation laws catalyzed by IOT were studied in detail. When the dosage of IOT was 300 mg·L−1 and that of H2O2 was 1700 mg·L−1, up to 99.6% of TC-HCl was degraded within 360 min, demonstrating the excellent catalytic efficiency of IOT. As a heterogeneous catalyst, IOT showed satisfactory pH suitability and could be used in a pH range from 1.6 to 11.6. IOT also showed satisfactory cyclic stability, with the catalytic degradation rate of TC-HCl only decreasing from 99.6% to 95.1% after 10 cycles. The Fe elements endowed in IOT promote the generation of ·OH and ·O2- in the presence of H2O2, which helps to scavenge organic pollutants. The mineral composition of IOT also facilitates the catalytic process.

Efficient degradation of methylene blue by FeS2/MoS2 in heterogeneous Fenton-like process

Iron-based materials as Fenton catalysts exist the problems of low activation efficiency of hydrogen peroxide (H2O2) and narrow applicable pH range. Herein, we synthesized materials with different ratios of molybdenum to iron, named as MoS2/FeS2, and used them for the degradation of methylene blue (MB). Notably, the MB degradation rate of FeS2/MoS2/H2O2 system reached 99.9 % within 30 min under neutral conditions, and its degradation rate constant was 34.3 and 21.8 times than that of MoS2 alone and physical mixture of FeS2 + MoS2, respectively. The MB degradation rate was 81.4–99.9 % at solution pH of 3–11, suggesting that FeS2/MoS2 is applicable to the Fenton-like process at wide pH. The morphology and composition of materials were analyzed by X-ray diffraction (XRD), Barrett-Emmett-Teller (BET), Transmission electron microscopy (TEM) and Scanning electron microscope (SEM). The X-ray photoelectron spectroscopy (XPS) and experimental results showed that Mo and S accelerated Fe2+/Fe3+ cycling was the main reason for the enhancement of catalyst activity. The main reactive oxygen species (ROS) was singlet oxygen (1O2) in the system. After 4 applications of FeS2/MoS2, the MB degradation rate still reached more than 90 % within 30 min, which indicates the excellent stability of material. In summary, FeS2/MoS2 has promising prospects for the degradation of wastewater.

Facilely prepared heterogeneous Fenton catalyst Fe(Fe0.69Al0.31)2O4@C for catalytic wet peroxide oxidation of ciprofloxacin in batch and continuous reactor: Reaction intermediates and toxicity evaluation

Herein, by using a simple co-precipitation method Al-doped magnetite spinel nanoparticle encapsulated in the carbon matrix Fe(Fe0.69Al0.31)2O4@C was synthesised and its catalytic activity was examined as a heterogeneous Fenton catalyst towards the catalytic wet peroxide oxidation (CWPO) of antibiotic pollutant 20 ppm ciprofloxacin (CIP) in batch and continuous reactors. Under the optimized conditions, 0.5 g·L-1 Fe(Fe0.69Al0.31)2O4@C in batch reactor mineralized 51 % of CIP was achieved within 180 min at 50 °C and pH 3 by utilizing 1.2 mM or 4S H2O2 (S = stoichiometry; 47 mol H2O2:1 mol CIP) which is significantly less concentration compared to other heterogeneous Fenton catalysts. Impressive long-lasting catalytic activity was demonstrated in the up-flow fixed bed reactor, for 110 h with 44 % TOC removal and less than 1 ppm Fe leaching in the effluent water. Kinetic studies on the rate of decomposition of H2O2 revealed that Fe(Fe0.69Al0.31)2O4@C effectively decomposed the H2O2 like the homogeneous Fenton catalyst. The XPS results confirmed the influence of Al on iron ions in the magnetite structure through a substantial shift in higher binding energy for Fe3+ and introduced a more electropositive character on the Fe3+(δ+) that successively expedites the kinetically slow Fe3+ reduction reaction with H2O2 to produce HOO•. The π electrons of the graphitic carbon facilitate the electron transfer between the carbon matrix and Fe(Fe0.69Al0.31)2O4 nanoparticles to enhance the CIP degradation. The acute toxicity assessment studies validated the non-toxic nature of the effluent water obtained from batch and continuous reactors. A degradation pathway was proposed based on the eleven intermediate products identified using LC-HRMS analysis.

Applying bottom ash as an alternative Fenton catalyst for effective removal of phenol from aqueous environment.

In this study, coal bottom ash from a thermoelectric plant was tested as an alternative Fenton catalyst for phenol degradation in water. The effect of operating parameters such as initial pH, catalyst dosage and H2O2 concentration were evaluated. The characterization results indicated that the material has a mesoporous structure, with active species (Fe) well distributed on its surface. Under the optimal reaction conditions (6mM H2O2, 1g L-1 of catalyst and pH = 3), 98.7% phenol degradation efficiency was achieved in 60min, as well as 71.6% TOC removal after 150min. Hydroxyl radical was identified as the main oxidizing agent involved on the cleavage of the phenol molecule. After four consecutive reuse cycles, phenol degradation efficiency was around 80%, indicating good reusability and stability of the catalyst. Therefore, the obtained results demonstrated that the bottom ash presents remarkable activity for application in the Fenton reaction towards phenol degradation.

Nanoparticles of HNO3-Treated Clinoptilolite Load with Iron: An Innovative Approach for Magnetic Recovery of Fenton Catalyst

Nanoparticles of HNO3-Treated Clinoptilolite Load with Iron: An Innovative Approach for Magnetic Recovery of Fenton Catalyst

Development of Highly Efficient Heterogeneous Fe3O4‐Biochar Nanocomposite as Fenton‐like Catalysts for Degradation of Fast Green

AbstractIron oxide and its carbon‐containing biochar have shown efficiencies in Fenton oxidation reactions in recent years. Though magnetic biochar composites have been reported, developing facile, environment‐friendly methods with appropriate activity remains challenging. Removing dye traces from aqueous solutions is a prime concern under water scarcity issues at different levels. We developed a catalyst of biochar with magnetite for dye remediation. Magnetite is homogeneously loaded on biochar surfaces to form Fe3O4‐biochar to efficiently activate H2O2 to achieve hydroxyl radicals. This catalyst degrades Fast green dye efficiently around 89.3 % within 60 min with the optimum reaction conditions of 15 mM Fast Green dye, pH=4, 30 mg of Fe3O4‐biochar and 25 mM of H2O2. The composite shows around 41 % increase in the degradation rate after incorporating the Fe3O4 on biochar. The prepared Fe3O4‐biochar composite can be easily recycled without significant activity loss for five successive degradation reactions. The reported study provided a direction to prepare newer Fenton catalysts from sustainable sources for the degradation of organic dyes in water and overcame individual limitations of Fe3O4 and biochar.

Application of FeOOH nanorods as a heterogeneous Fenton catalyst: The Matter of aspect ratio

Due to the growing global population and shift towards industrialized societies, water pollution and the management of wastewater are becoming significant issues. Hence, there is a need for innovative approaches to remove contaminants from effluent streams to protect the environment and human health. The Fenton's reaction is an established method for wastewater treatment, and iron oxide hydroxide (FeOOH) nanorods have immense potential as heterogeneous Fenton catalysts. The catalytic potency of nanorods is determined by their morphology, especially their length. Therefore, this study aimed to synthesize FeOOH nanorods of different mean lengths (49–101 nm) and evaluate their catalytic activity in a Fenton's reaction. Nanorods with an average length of 78 nm had the highest catalytic activity, and 87% of methyl orange was degraded over the reaction. The greater catalytic activity of these nanorods can be attributed to their larger surface area compared to the other investigated sizes. FeOOH nanorods have a porous structure; thus, their surface area is not directly related to their particle size. These outcomes indicate that the porosity and surface area play a significant role in determining the performance of heterogeneous catalysts and, as a result, must be considered to develop efficient catalysts for environmental remediation.

MIL-88A-based Antifouling Superhydrophilic Membrane for Efficient Emulsion Separation and Dye Degradation via Photo-Fenton Process

Pollution of oily wastewater is a serious worldwide environmental problem that causes serious harm to the environment and human beings, while at the same time, emulsifier and dye wastewaters pose great difficulties for wastewater treatment. In a previous study, MIL-88A as an iron-based metal-organic frameworks (MOFs) has good hydrophilicity and large specific surface area, in addition, it acts as a Fenton catalyst, generating strong oxidizing hydroxyl radicals under the condition of UV light and hydrogen peroxide to achieve efficient degradation of dyes. Inspired by this, we prepared nano-needle zinc oxide on stainless steel mesh (SSM) by electrochemical method, and then prepared MIL-88A-based superhydrophilic membranes by spraying method, which can easily separate a variety of oil-in-water emulsions. After 10 emulsion separations, the separation efficiency of the prepared membrane was still as high as 99.5 %. In addition, the prepared membranes have a high removal rate of methylene blue (MB), degrading 98 % of MB in 35 min, and remain underwater superoleophobic even after 50 cycles of sandpaper abrasion. This robust mesh for efficient emulsion separation and dye removal shows great potential for oily wastewater treatment and water quality remediation.

Preparation of Fenton Catalysts for Water Treatment

In the heterogeneous Fenton reaction, a solid catalyst reacts with H2O2 to generate highly oxidizing free radicals, that degrade organic pollutants in aqueous solutions. In this study, impregnation calcination was used to modify activated carbon and load it with various metal compounds. The synergistic catalysis of the various metal compounds showed improved catalytic activity, and the prepared heterogeneous Fenton catalyst exhibited high catalytic activity, a wide pH range, and good stability. The concentration ratios of the Fenton catalyst impregnation solutions-were as follows: Fe3+, Cu2+, Mn2+, and Ce3+ at 0.45, 0.72, 0.19, and 0.11 mol/L, respectively. The optimal sintering temperature of AC impregnation was determined through TGA/DSC, SEM, SEM-EDS, XPS, and XRD testing. At a final calcination temperature of 900 °C, the degradation efficiency of 10 ppm methylene blue reached 98.25% at pH 5 with 5 mM H2O2. After ten soaking cycles, the degradation efficiency exceeded 90%. The structure and performance of the catalysts were characterized using EPR, BET, ICP, and UV spectroscopy, demonstrating the excellent performance of the catalyst and providing an improved treatment plan for solving wastewater problems.

Carbon/iron co-product from clean hydrogen production as a tri-functional adsorbent and catalyst for efficient wastewater treatment

Clean hydrogen production via methane pyrolysis (CH4 → 2H2 + C) generates large quantities of solid carbon. Realizing their applications is a critical gap to enable its broader adoption. Here, we show that carbon nano onions encapsulated with iron cores (Fe@CNO) produced in CH4 pyrolysis using low-cost Fe ore catalysts can serve as a tri-functional adsorbent and catalyst for organic contaminant degradation. Fe@CNO has a high adsorption capacity and fast pseudo-second-order adsorption kinetics for antibiotics in wastewater. Surface oxidized Fe@CNO presents a high catalytic activity for in situ hydrogen peroxide production. Fe@CNO is also an efficient heterogeneous Fenton catalyst to degrade adsorbed antibiotics. Further, the Fe core is magnetic, enabling easy separation from solvents as reusable adsorbents and catalysts. We demonstrate that the adsorption and electro-Fenton process applies to various organic pollutants in different water matrices. This opens a new strategy for utilizing co-products from H2 production for sustainable environmental applications.

Enhanced photo-Fenton catalytic activity over Cu-doped Bi12O17-xCl2 nanotube for tetracycline degradation: Oxygen vacancies-induced mixed valent Cu

Fenton photocatalyst constructed by transition metal-doped semiconductor material seems to be a promising alternative to classic Fenton catalysts. A series of Cu-doped tubular Bi12O17Cl2 with sufficient oxygen vacancies (ov) was successfully prepared through a hydrothermal method. The formation of ov in the Bi12 crystal lattice can favor the Fenton reaction not only by serving as a reaction site and increasing the charge density in the photocatalyst but also by partially reducing the dopant Cu2+ to Cu+, which consequently enhances the H2O2 activation to a significantly higher rate. Notably, Cu-doped Bi12O17Cl2 ov with an optimal dopant proportion of 4 % exhibited a preferable Fenton catalytic rate 4.5 times higher than pure photocatalytic degradation. This work investigates the mutual promotion of oxygen vacancies and dopant ions in the Fenton reaction and provides a novel development scheme for the advanced oxidation process.

Progress in wastewater treatment via organic supramolecular photocatalysts under sunlight irradiation

Semiconductor photocatalysis offers a promising and sustainable avenue for wastewater treatment due to its ease of separation and recyclability. However, their practical application is currently hampered by limited energy utilization, insufficient mineralization, and low treatment capacity under sunlight. This account summarizes our progress in developing broad-spectrum responsive (extended to 950 nm) supramolecular organic photocatalysts capable of sunlight-driven over 95% pollutant mineralization. Through modulation of molecular dipole and crystallinity, we enhance the built-in electric field, thereby improving charge separation and photodegradation rates. Furthermore, to overcome the low-flux constraints of traditional photocatalysis, we integrated the Fenton catalyst to construct photo-self-Fenton systems, realizing a 29.63 L m2 h1 high-flux mineralization under sunlight. Finally, a brief conclusion and outlook on organic photocatalysts have also been presented.

FeOCl/WS2 composite as a heterogeneous Fenton catalyst to efficiently degrade acid orange II

FeOCl/WS2 composite as a heterogeneous Fenton catalyst to efficiently degrade acid orange II

Surface boric acid modification promoted Fe3+/Fe2+ cycle and H2O2 activation for facilitating Fenton degradation performance of Bi2Fe4O9

Boric acid (H3BO3) modified Bi2Fe4O9 (H3BO3@Bi2Fe4O9, BBFO) materials were prepared by surface H3BO3 treatment on Bi2Fe4O9 (BFO) employing mechanical ball milling method. XPS analysis and FT-IR spectra demonstrates that H3BO3 was successfully fastened on BFO surface through intense friction and collision between mixed powder (H3BO3 and BFO) and abrasive. And EPR result illustrates that the more abundant oxygen vacancy (OVs) has been introduced into BFO surface in H3BO3 modification process. The Fenton degradation rate for oxytetracycline (OTC) of BBFO-2 materials reaches 75.0 % within 60 min, which is 21.8 % higher than that of BFO treated by ball milling process without H3BO3 modification (HBFO). And the H2O2 utilization rate (23.4 %) of BBFO-2 materials is higher than that of HBFO (7.6 %), which ascribes to the H3BO3 modification and the introduction of abundant OVs by the surface electrons accumulation and transfer for strengthening the Fe3+/Fe2+ cycle and H2O2 decomposition. The possible degradation pathways and Fenton reaction mechanism was speculated by ESR and HPLC-MS analysis. The manuscript provides a scientific reference and theoretical basis for investigating the preparation and enhancement mechanism of surface modification strategy for Fe-based Fenton catalysts.

An Investigation of PPy@1T/2H MoS2 Composites with Durable Photothermal-Promoted Effect in Photo-Fenton Degradation of Methylene Blue and in Water Evaporation.

MoS2 has garnered considerable attention as an exceptional co-catalyst that is capable of significantly enhancing the efficiency of H2O2 decomposition in advanced oxidation processes (AOPs). This improvement allows for a reduction in the required amounts of H2O2 and Fe2+. In this study, we investigated the cyclic durability of photo-Fenton catalysts, focusing on the degradation of pollutants through the introduction of PPy into heterogeneous 1T-2H MoS2 units. The resulting photothermal-Fenton catalysts, comprising non-ferrous Fenton catalysts, demonstrated excellent degradation performance for simulated pollutants. In comparison with 1T-2H MoS2, the PPy@1T-2H MoS2 composite exhibited remarkable stability and photothermal enhancement in the photo-Fenton degradation of methylene blue (MB) under visible light irradiation. The photo-Fenton reaction efficiently degraded contaminants, achieving 99% removal within 5 min and 99.8% removal within 30 min. Moreover, the co-catalyst complex displayed enhanced cyclic stability during the photo-Fenton reaction, with a contaminant removal efficiency of 92%, even after the 13th cyclic test. The combined effects of PPy and 1T-2H MoS2 demonstrated improved efficiency in both photocatalytic and photo-Fenton catalytic reactions. Furthermore, PPy@1T-2H MoS2 exhibited outstanding performance in the photothermal evaporation of water, achieving an efficiency of 86.3% under one solar irradiation.

Cu2O/Fe3O4/UiO-66 nanocomposite as an efficient fenton-like catalyst: Performance in organic pollutant degradation and influencing factors based machinelearning

The persistent presence of organic pollutants like dyes in water environment necessitates innovative approaches for efficient degradation. In this research, we developed an advanced hybrid catalyst by combining metal oxides (Cu2O, Fe3O4) with UiO-66, serving as a heterogeneous Fenton catalyst for for efficient RB19 breakdown in water with H2O2. The control factors to the catalytic behavior were also quantified by machine learning. Experimental results show that the catalytic performance was much better than its individual components (P < 0.05 & non-zero 95% C.I). The improved catalytic efficiency was linked to the occurrence of active metal centers (Fe, Cu, and Zr), with Cu(I) from Cu2O playing a crucial role in promoting increased production of HO•. Also, UiO-66 served as a catalyst support, attracting pollutants to the reaction center, while magnetic Fe3O4 aids catalyst recovery. The optimal experimental parameters for best performance were pH at 7, catalyst loading of 1.6 g/L, H2O2 strength of 0.16 M, and reaction temperature of 25 °C. The catalyst can be magnetically separated and regenerated after five recycling times without significantly reducing catalytic activity. The reaction time and pH were ranked as the most influencing factors on catalytic efficiency via Random Forest and SHapley Additive exPlanations models. The findings show that developed catalyst is a suitable candidate to remove dyes in water by Fenton heterogeneous reaction.

Efficient degradation of refractory pollutant boosted by combining heterogeneous electro-Fenton on the hydrophobic modified gas diffusion electrode with anodic oxidation

To boost refractory pollutant removal over a broad pH range, we here proposed an integrated electrocatalytic process combining electrochemical anodic oxidation (AO) with cathodic electro-Fenton (EF) based on a hydrophobic modified gas diffusion electrode and heterogeneous Fenton catalyst of FeOCl. Total organic carbon (TOC) removal of refractory levofloxacin by EF + AO process was 85% in 120 min under the applied potential of −0.6 V and pH ∼6.7, obviously higher than that of only AO (22%) or EF (62%) process. Significantly, EF+AO process was demonstrated to be efficient and stable for actual wastewater treatment that chemical oxygen demand (COD) value of refinery wastewater after EF + AO treatment was steadily met the discharge standard (GB 18918–2002) for sewage treatment plants in China (I-A: COD < 50 mg/L) during 100 h of consecutive runs. Our results provide new insights into developing an energy-efficient electrocatalytic technology for enhancing refractory pollutant removal.

Ascorbic acid enhanced CuFe2O4-catalyzed heterogeneous photo-Fenton-like degradation of phenol

CuFe2O4 particles were synthesized using the sol-gel self-combustion method and characterized for their compositional surface morphology and crystal structure. When compared to the photo-Fenton system without ascorbic acid (AA), the presence of AA significantly enhanced the catalytic degradation of phenol using CuFe2O4. The highest catalytic degradation efficiency was achieved at an AA concentration of 1 mmol/L, resulting in up to 98.6 % elimination of phenol in just 40 min. The reaction rate was found to be 31.7 times higher than that of the system without AA. The mechanism of AA enhancement in the CuFe2O4 photo-Fenton system was further investigated. Two key factors were found to contribute to the enhancing mechanism of AA introduction in the CuFe2O4 photo-Fenton system. Firstly, AA promoted the Cu/Fe redox cycle on the catalyst surface, leading to a more efficient generation of reactive species that are responsible for phenol degradation. Secondly, AA accelerated the leaching of metal ions from the catalyst surface, facilitating the homogenous Fenton effect. The Cu/Fe bimetallic cycle system offers new perspectives on effective Fenton catalyst design and provides crucial insights for reductant-enhanced photo-Fenton activation.

Fabrication of Self-Assembled BiFeO3/CeO2 Nanocatalytic Materials for Efficient Catalytic Dye Degradation.

The catalytic treatment of wastewater serves as an effective way to solve the problem of water pollution, in which non-homogeneous Fenton catalysts are widely used. However, the activity enhancement of non-homogeneous Fenton catalysts still remains a great challenge. Herein, self-assembled BiFeO3/CeO2 nanocatalytic materials with different molar ratios were successfully fabricated by a suspension blending method, following which the structure evolution was determined by various characterizations. The catalytic degradation of methylene blue (MB), rhodamine B (RhB), and saffron T (ST) were performed over the BiFeO3/CeO2 nanocatalytic materials. It was found that the 0.2BiFeO3:0.8CeO2 nanocatalytic materials exhibited an 80.8% degradation efficiency for RhB. The 0.6BiFeO3:0.4CeO2 nanocatalytic materials reached 81.1% and 48.7% for ST and MB, respectively. The BiFeO3/CeO2 nanocatalytic materials also showed a good stability during several cycles. The combination of CeO2 with BiFeO3 led to an enhanced activity for dye degradation, probably due to the electron transfer from ≡Fe2+ to ≡Ce4+. This study provides a new approach to dye degradation by using Fenton catalytic systems.