Fenton-like Degradation Research Articles

Oxidative hydrothermal carbonization to fabricate versatile magnetic biochar for Fenton-like degradation of phenolic compounds

Magnetic biochar (MBC) has drawn great attention as a versatile catalyst for advanced oxidation elimination of pollutants from aqueous solution with synergy of iron species and carbon matrix. Herein, an MBC was manufactured by oxidative hydrothermal carbonization employing potassium ferrate as precursor and internal oxidant for Fenton-like degradation of phenols in aqueous solution. This unique oxidative hydrothermal carbonization allowed multiple iron species to be introduced with persistent free radicals (PFRs), providing diverse catalysis sites for activating H2O2 into reactive oxygen species (ROSs) for efficient degradation of phenols. Moreover, graphite structure was generated with abundant oxygen functional groups, benefiting to accelerating Fe3+/Fe2+ cycle by electron shuttle and transfer. The catalysis degradation efficiency was up to 99.74 % with 44.4 % of total organic carbon (TOC) removal rate for 75 mg L−1 of phenol using 0.2 g L−1 MBC dosage. Satisfactory recyclability was achieved for the MBC as the catalysis degradation efficiency slightly decreased from 99.74 % to 87.95 % after five times recycling. Moreover, the MBC catalysis system exhibited extensive applicability in real water matrices and for degradation of different phenols with high efficiency. Serving as a demonstration of oxidized magnetic biochar for efficient Fenton-like degradation of phenols, this work highlighted the great potential of oxidative hydrothermal carbonization in preparation of high performance magnetic biochar.

Synthesis of Fe3O4 Derived from Acid Mine Drainage (AMD) Sludge and Catalytic Degradation of Tetracycline.

Acid mine drainage (AMD) sludge is waste generated in the process of acid mine wastewater treatment, and the use of AMD sludge to prepare Fe3O4 to activate H2O2 degradation pollutants is an effective means of resource utilization. In this study, the heterogeneous catalyst Fe3O4-based composites were synthesized by a one-step method using AMD sludge as a raw material, and the Fe3O4-based materials before and after catalysis were characterized by powder diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), and scanning electron microscopy (SEM). The effects of several key factors (pH values, H2O2 content, TC concentration, and Fe3O4 content) of tetracycline (TC) degradation were evaluated. The results revealed that the TC removal rate reached up to 95% within 120 min under optimal conditions (pH 3; H2O2, 5 mmol/L; TC concentration, 25 mg/L; Fe3O4 content, 1g/L). Moreover, •OH and •O2- radicals were generated during the Fenton-like degradation process, and the plausible degradation mechanism was discussed. Besides, the Fe3O4 catalyst exhibited fantastic stability after five cycles. In conclusion, this study is expected to promote the resource utilization of industrial sludge and provide a new material for the treatment of antibiotic-contaminated wastewater.

Fe-based monolithic catalysts for Fenton-like degradation of organic dyes: The important role of Fe2(OH)3Cl species

Fe-based monolithic catalysts for Fenton-like degradation of organic dyes: The important role of Fe2(OH)3Cl species

Multifunctional property of N,N-bis (carboxymethyl) glutamic acid modified biomass material: adsorption and degradation removals of cationic dyes in wastewater

As a common type of pollutants in industrial wastewater, cationic dyes have attracted great attentions. Using biodegradable N,N-di (carboxymethyl) glutamic acid (GLDA) as ligand and corn stalk (CS) as matrix, a novel and green biomass modified material GLDA-CS was successfully prepared. The multifunctional property of GLDA-CS for removing methylene blue (MB), malachite green (MG) and alkaline red 46 (R-46) from wastewater was evaluated. The dyes were removed by the electrostatic adsorption based on the cationic adsorption properties of GLDA-CS. The removal rates of MB, MG and R-46 can quickly reach 90.4%, 96.8% and 94.8% in short time. especially for MG and R-46 even only 20 min. The adsorption capacities of the dyes still remain more than 86.5% of the initial values after 5 cycles. In a heterogeneous system, the dyes were removed by Fenton-like degradation based on the metal chelating property of GLDA-CS. 100% degradation rates of the dyes can be achieved in 35 min under the acidic region. Even if at pH 7, degradation rates are 44.1%, 47.1% and 56.6% higher than those under the conventional homogeneous system, and the degradation rate remained at 83.7% after 5 cycles. Regardless of the adsorption or degradation, GLDA-CS shows strong anti-anion interference ability. The potential mechanisms of adsorption and degradation for the dyes by GLDA-CS were deduced by quantization calculation. It is concluded that the adsorption removal of the dyes by GLDA-CS follows MG > R-46 > MB, and mainly depends on the electrostatic interaction between -COOH in GLDA-CS and -N- in the dye molecules. Based on the degradation mechanism of Fenton-like reaction, the possible active sites of the dyes attacked by free radicals and their possible degradation intermediates were predicted by the calculations of Fukui function.

In-situ growth of three-dimensional copper-based catalyst in 4A zeolite/PES mixed matrix membrane for Fenton-like degradation of phenol

Fenton-like membrane reactors applied to water purification provide a broad solution to address the challenges of catalyst recovery, low reaction efficiency, and high mass transfer resistance in heterogeneous batch reactions. Zeolites as nanocatalyst carriers are promising candidates for advanced purification membranes. Herein, we report a composite catalytic membrane (4A-Cu/PES) for Fenton-like degradation of phenol wastewater, fabricated by in-situ growth of copper nanoflowers on a 4A zeolite/polyethersulfone (PES) mixed matrix membrane, forming a three-dimensional core-shell nanostructured catalyst. Compared with the conventional method, the in-situ growth prevents the copper catalyst from being covered by the polymer and significantly increases the copper loading (3.97 %), thus ensuring efficient catalytic reactions within the membrane pores. Meanwhile, the porous structure of zeolite provides a large specific surface area, facilitating uniform dispersion of copper ions during in situ growth of the catalyst and providing abundant active sites. The membrane exhibited a phenol degradation rate of 93.9 % at pH 6, significantly broadening the pH applicability of the Fenton reaction. Hydroxyl radicals (·OH) were identified as the primary active species in the 4A-Cu/PES-H2O2 system. Moreover, the membrane retained high catalytic activity after five cycles, demonstrating excellent stability. This work provides important insights for designing efficient and stable Fenton-like zeolite catalytic membranes.

Photothermal nano-confinement reactor with bimetallic sites for enhanced peroxymonosulfate activation in antibiotic degradation

In recent years, photothermal-assisted Fenton-like degradation of organic pollutants has become a prominent green method in environmental pollution control. Nevertheless, the design of suitable catalysts remains a significant challenge for this approach. Herein, zeolite-imidazolate framework-derived CoMn bimetallic nanoparticles embedded in hollow carbon nanofibers (CoMnHCF) have been developed as a photothermal nano-confinement reactor with multiple active sites to enhance reaction performance and promote peroxymonosulfate (PMS) activation. Under light irradiation, the local temperature within the porous spaces of CoMnHCF was significantly higher than the liquid temperature. The confined space concentrated heat, minimized thermal loss, and effectively utilizes this feature to activate PMS for antibiotic degradation. The results demonstrated that this system efficiently degraded various antibiotics, including tetracycline hydrochloride, levofloxacin, sulfamethoxazole, norfloxacin and chlorotetracycline. Photothermal contribution analysis revealed that thermal effects predominate in this system. Further DFT simulations explored the coordination environment of metal elements and the properties of related pollutants, predicting potential structures and reaction sites. A series of water quality experiments and cyclic tests demonstrated the system's significant application potential. This study offered new insights into advancing the integrated use of photothermal conversion and nano-confinement reactor activation of PMS in sewage purification.

Customizable Three-Dimensional Printed Zerovalent Iron: An Efficient and Reusable Fenton-like Reagent for Florfenicol Degradation.

Zerovalent iron (Fe0)-based Fenton-like technology has great potential for treating recalcitrant organic pollutants (ROPs) in wastewater. However, rapidly and precisely manufacturing Fe0-based materials with the desired geometries is challenging. Herein, novel three-dimensional printed Fe0 (3DP-Fe0) and bimetallic 3DP-Ni/Fe0 were customized by 3D printing for efficient Fenton-like degradation of florfenicol (FLO), a typical antibiotic in wastewater. 3DP-Ni/Fe0 with hydrogen peroxide (H2O2) exhibited superior reactivity toward FLO than 3DP-Fe0, generating hydroxyl radicals (·OH) and atomic hydrogen to achieve >90% dehalogenation and >70% total organic carbon removal within 10 min. The resulting degradation intermediates possessed lower antibacterial activity than FLO and did not cause resistance gene proliferation in activated sludge. The Fenton-like activity of 3DP-Ni/Fe0 was similar across different shapes but increased with increasing porosity and size. Compared with powdered Ni/Fe0, 3DP-Ni/Fe0 exhibited faster electron transfer during Fe(II)/Fe(III) cycling, which increased the utilization efficiency of dissolved Fe2+ and H2O2 for ·OH production. Moreover, 3DP-Ni/Fe0 could be reused >150 times, 5-fold more than powdered Ni/Fe0, owing to its lower metal ion release and Fe0 depletion. 3DP-Ni/Fe0 with H2O2 can also efficiently remove chemical oxygen demand from real wastewater and other ROPs (e.g., acetaminophen, carbamazepine, thiamphenicol, and tetrabromobisphenol A).

Photocatalytic Fenton-like degradation of Acid Green 25 by novel aluminum nanoferrites with persulfate: Optimization by response surface methodology

Magnetic nanomaterials are gaining increasing attention for their catalytic properties and ease of recovery, making them promising candidates for the degradation of various organic pollutants. In this study, AlFe2O4 nanoparticles were employed for the first time in photocatalytic wastewater treatment. The study focused on removing Acid Green 25 anthraquinone dye through persulfate activation under UV-Visible light. AlFe2O4 nanoparticles were synthesized via sol-gel auto-combustion method and characterized by various techniques (XRD, SEM, EDX, VSM, Raman and FTIR). Moreover, statistical analysis of the experimental data confirmed the strong performance of the RSM model in accurately representing the photocatalytic process. Under optimal conditions including persulfate and catalyst concentrations of 0.3 g/L and 0.83 g/L respectively, a solution pH of 3 and 45 minutes of contact time, a 96 % dye removal rate was achieved. The remaining persulfate concentration was 60 % and fully depleted within 90 minutes, indicating efficient activation by AlFe2O4 photocatalyst. The activation process effectively suppressed electron-hole recombination, enhancing the overall efficiency. Scavenger experiments further identified surface-bound radicals and photogenerated holes as the main reactive species. A degradation mechanism for AG25 dye via a photocatalytic Fenton-like process was proposed, highlighting dual synergistic catalysis in the dye degradation. Ecotoxicity assessments using Vibrio fischeri bioassay revealed a significant reduction in toxicity after treatment with AlFe2O4/PS/UV-Vis system. The stability of AlFe2O4 was demonstrated over five degradation cycles. The findings open new perspectives for the use of AlFe2O4 in advanced wastewater treatment technologies, positioning it as a promising material for the degradation of persistent pollutants.

Adsorption and catalytic degradation of Light green SF by magnetic PEI-modified carbon nanotubes composites

Treatment of colored effluent is necessary for the textile industry. In this study, a magnetically recyclable composite (MnFe2O4@cCNTs-PEI) was prepared by coprecipitation and grafting methods, and its efficiency for removal of light green SF (LG) from solution assessed via the adsorption and advanced oxidation techniques. The experimental results indicated that the maximum adsorption capacity of MnFe2O4@cCNTs-PEI towards LG could reach 371 mg‧g−1 at solution pH 3 and 303 K. The adsorption equilibrium results could be well fitted by Koble-Corrigan, Temkin, and Freundlich isotherm models whereas the adsorption kinetic process follows the Elovich equation and Double Constant model. This implies the adsorption process be heterogeneous multimolecular layer adsorption, accompanied by heterogeneous diffusion. The adsorption process was spontaneous, endothermic and entropy increasing which was majorly controlled by the electrostatic attraction and π-π stacking mechanisms. MnFe2O4@cCNTs-PEI can catalyze and activate H2O2 to achieve a heterogeneous Fenton-like degradation of LG. MnFe2O4@cCNTs-PEI as a catalyst could achieve a higher removal rate of LG (90 %) within a broad pH range (3–10) which could be ascribed to the presence of active radical species such as ‧OH and 1O2. After three adsorption and degradation regeneration cycles, the removal rate of LG was still higher than 60 %. It is potential for MnFe2O4@cCNTs-PEI to be economically viable for practical applications.

Magnetic activated carbon for the removal of methyl orange from water via adsorption and Fenton-like degradation

Water pollution caused by organic dyes is a critical environmental issue. Although activated carbon (AC) is commonly used for dye adsorption, its effectiveness is limited by challenges in separation and regeneration. To address these limitations, a convenient recyclable magnetic activated carbon (MAC) was fabricated via co-precipitation and calcination method, serving as adsorbent and catalyst for methyl orange (MO) removal through a Fenton-like degradation process. Characterization techniques, including XRD, FTIR, SEM and TEM, confirmed that Fe3O4 nanoparticles (10–20 nm) were uniformly dispersed on AC surface. The MAC maintaining a high surface area (997 m2/g) and pore volume (0.795 cm3/g) and exhibited superparamagnetic properties with a saturated magnetization of 5.52 emu/g, enabling effective separation from aqueous solutions by magnet. Batch adsorption studies revealed that MO adsorption onto MAC followed pseudo-second-order kinetic and Freundlich isotherm model, with a maximum adsorption capacity of 205 mg/g at 25 °C. Thermodynamic analysis showed that the adsorption process was spontaneous and endothermic. Simultaneous degradation of MO and in-situ regeneration of MAC were achieved via Fenton-like reaction using sodium persulfate (PS). Under a PS concentration of 9 mmol/L, the MO removal efficiency near 95% after 60 min, with a total organic carbon (TOC) reduction of 83.1%. The reaction of Fe3O4 and oxygen functional groups on AC surface with PS facilitated the generation of SO4•-, thereby enhancing catalytic degradation of MO. The degradation efficiency improved as the temperature increased from 25 °C to 45 °C. Cycle tests demonstrated that the MO removal efficiency of MAC remained above 90% after 5 cycles of regeneration. Overall, this study highlights the potential of MAC for efficient removal of organic dyes from water through the coupling of adsorption and Fenton-like degradation, providing a promising solution for addressing water pollution challenges.

Engineering of a wafer-shaped titanium-based catalyst of TiO2/MIL-125(Ti)@Ti3C2 for enhanced Fenton-like degradation of Congo red: Optimization, mechanistic study, and reusability

A titanium-based Fenton-like heterogeneous catalyst was synthesized from titanium dioxide (TiO2), MIL-125(Ti), and Ti3C2 MXene for degrading the notorious Congo red (CR). The successful combination of the titanium components was assured by bountiful characterization apparatuses. Optimization of the conditions for the Fenton-like degradation of CR dye was performed by studying the impact of the pH and temperature of the catalytic system, the dosage of TiO2/MIL-125(Ti)@Ti3C2, the concentrations of hydrogen peroxide (H2O2) and CR, and the mass ratio between the catalyst’s components. A kinetic study was executed on the degradation of CR and H2O2 during a reaction time of 60 min using First-order and Second-order models. The degradation pathway of CR by TiO2/MIL-125(Ti)@Ti3C2 was investigated by the scavenging test. Additionally, Adsorption and catalytic degradation mechanisms were explored using X-Ray Photoelectron Spectroscopy (XPS) analysis. The cycling test proceeded on TiO2/MIL-125(Ti)@Ti3C2 for five succeeding Fenton-like degradation runs of CR dye. Ultimately, the Ti-based heterogeneous catalyst exhibited superior adsorption and Fenton-like degradation performance toward the anionic dye with a good recyclability feature.

Design and characterisation of activated magnetic zeolite 4A from naturally occurring kaolin clay of Cameroonian origin for optimised dye removal by Fenton-like degradation

ABSTRACT The transformation of local clay material of Cameroonian origin into magnetic zeolite (Fe@Zeo-4A) for the degradation of acid-blue 90 in solution was investigate herein. The insertion of magnetic iron oxide particles into the zeolitic framework of Zeo-4A was achieved via hydrothermal synthesis. FT-IR spectroscopy, XRD and SEM confirmed the transformation of the clay into zeolite while EDX analysis and elemental mappings confirmed the presence of iron in the magnetic zeolite. Fe@Zeo-4A was strongly attracted to an external magnetic field. N2 adsorption-desorption studies revealed a considerable decrease in specific surface area and pore volume from the zeolite to the magnetic zeolite, suggesting the occupation of the pores of the zeolite by magnetite. The central composite design of the response surface methodology was used as optimisation approach for four parameters affecting the efficiency of degradation: solution pH, H2O2 concentration, initial dye concentration and time of stirring. ANOVA results revealed good correlation between the experimental and predicted results as well as the suitability of the linear regression model for describing the dye degradation process. An adjusted correlation coefficient of 85.17% was obtained for the dye degradation model. An optimal degradation percentage of 95.2% was obtained experimentally under optimal conditions of 7.6 for pH, 20 mg/L for dye concentration, 15.0 mol/L for [H2O2] and 15 min for time, in close agreement with a theoretical response of 96.6% predicted by the model. The magnetic zeolite was found to exhibit good stability over a wide pH range and lost only about 18% of its catalytic efficiency after five cycles of degradation experiments. Therefore, the novel magnetic zeolite-based material is an efficient Fenton catalyst for treating dye-contaminated wastewater.

Fe Immobilized within Accordion-Like Tubular Carbon Nitride As a Catalyst for the Fenton-Like Degradation of Ranitidine: Synergetic Roles of •OH and 1O2

Fe Immobilized within Accordion-Like Tubular Carbon Nitride As a Catalyst for the Fenton-Like Degradation of Ranitidine: Synergetic Roles of ^•OH and ¹O₂

Cu-TNT hollow nanoreactors: Efficient Fenton-like degradation of organic pollutants across a wide pH range

Advanced oxidation processes (AOPs) operating under neutral to alkaline conditions are highly desirable for industrial applications. This study focuses on the use of Cu-doped titanate (Cu-TNT) hollow nanoreactors to effectively degrade organic pollutants in a Fenton-like manner across a broad pH from 3 to 10. The resulting Cu-TNT material possessed a BET surface area of 391.2 m2/g and pores with sizes between 2 and 20 nm. Experimental results from Fenton-like reactions reveal that Cu-TNT exhibited superior catalytic activity and long-term stability in degrading methyl orange compared to Na-titanate, Fe-titanate, copper ions, cuprous chloride, and solid sphere Cu-doped titanate. Notably, Cu-TNT performed optimally at a pH of 9, with singlet oxygen (1O2) and hydroxyl radicals (•OH) being recognized as the main active components. The improved catalytic efficiency was due to the extensive surface area, efficient mass diffusion in limited space, and quick Cu(Ⅰ)/Cu(Ⅱ) transformations. This study provided a feasible pathway to develop Cu-based nanoreactors as heterogeneous catalysts for highly efficient AOPs.

Enhancing Fenton-like degradation efficiency over a broad pH range through synergistic interactions among varied acidity sites in M1-O-M2 structures

This study introduced a novel catalyst, Cu-Fe@CTS (Chitosan)-ATP (attapulgite), which distinguished itself from traditional Fenton-like catalysts by effectively degrading pollutants across a broad pH range. This catalyst achieved impressive degradation rates of 200 mg L−1 of FA (Fulvic acid), reaching 97 % at pH = 3, 96 % at pH = 7, and 95 % at pH = 10. The catalyst’s enduring effectiveness, with FA removal rates marginal decrease to 94 % at pH = 3 after ten cycles, showcased its sustained catalytic activity. The underlying mechanism was attributed to a synergistic interaction facilitated by the addition of Cu2+ and Fe3+ into ATP’s framework, which generated a M1-O-M2 structure. Experimentation and analysis revealed a dynamic electron transfer mechanism within the M1-O-M2 structure. Moreover, the catalyst proved to be highly effective in treating real wastewater-leachate concentrate, underscoring its potential for environmental remediation across diverse pH conditions. This research laid the groundwork for expanding the pH applicability of catalysts, opening new pathways for advanced environmental clean-up strategies.

Partially amorphization induced S-scheme charge migration in g-C3N4/Mn1.1Fe1.9O4 defective heterojunction for boosting fenton-like degradation of tetracycline under visible light

S-scheme photo-Fenton catalyst is promising in water purification, whereas its rational design and carrier transfer mechanism remain a challenge. Here, a novel defective heterojunction via combining g-C3N4 with amorphous/crystalline Mn1.1Fe1.9O4 (Mn1.1Fe1.9O4-a/c) is fabricated for the degradation of tetracycline. The rich oxygen defects introduced by partially amorphization strategy can regulate the work function of Mn1.1Fe1.9O4-a/c, and switch the charge transfer path of g-C3N4/Mn1.1Fe1.9O4 from type-II to S-scheme, which demonstrates by ultraviolet photoelectron spectroscopy, in-situ kelvin probe force microscopy and density functional theory calculations. Driven by internal electron field, photogenerated electrons can transfer from Mn1.1Fe1.9O4-a/c to g-C3N4, which accelerated the separation of photoexcited carriers and H2O2 activation. Benefiting from the accelerated redox conversion with the action of bimetallic sites, oxygen defects and electrons, the g-C3N4/Mn1.1Fe1.9O4-a/c photocatalyst achieves 94.7 % tetracycline removal within 60 min, and the normalized kinetic rate exceeds reported works by 1–2 orders of magnitude. Multiple synergistic pathways lead to more reactive oxygen species generation, which achieves efficient mineralization of tetracycline (79.9 %). This work provides a simple partially amorphization strategy to switch charge transfer pathway from type-II to S-scheme for efficient water purification.

Mechanism of tartaric acid promoting CuO/H2O2 Fenton-like degradation of sarafloxacin

Tartaric acid (TA) as an organic assistant was investigated to degrade sarafloxacin (SARA) in an advanced oxidation process (AOP) with CuO catalyst. The promotional effect of TA is to activate H2O2 decomposition to •OH and HO2•/O2•- by accelerating the Cu(II)/Cu(I) redox cycle on the CuO surface while inhibiting 1O2 generation. TA could increase the conversion percentage of H2O2 to •OH from 18.47 % to 46.23 % and decrease the conversion percentage of H2O2 to O2 from 71.98 % to 45.64 % on CuO in 60 min. In addition, TA was further demonstrated to coordinate with the surface Cu(II) by forming Cu(II)-TA, which leads to an acidic environment and exposing more Cu active sites on the surface and releasing Cu2+ into aqueous solution, thus boosts the AOP. Adding TA into the reaction system not only improves the heterogeneous Fenton-like process (HFLP) but also promotes homogeneous Fenton-like process. In the SARA/TA/CuO/H2O2 system, •OH, HO2•/O2•- and 1O2 are the primary oxide species for SARA degradation. Plausible mechanisms for the degradation of TA and SARA were proposed as well.

Fenton-like Degradation of Methylene Blue on Attapulgite Clay Composite by Loading of Iron-Oxide: Eco-Friendly Preparation and Its Catalytic Activity.

The continuous discharge of organic dyes into freshwater resources poses a long-term hazard to aquatic life. The advanced oxidation Fenton process is a combo of adsorption and degradation of pollutants to detoxify toxic effluents, such as anti-bacterial drugs, antibiotics, and organic dyes. In this work, an activated attapulgite clay-loaded iron-oxide (A-ATP@Fe3O4) was produced using a two-step reaction, in which attapulgite serves as an enrichment matrix and Fe3O4 functions as the active degrading component. The maximum adsorption capacity (qt) was determined by assessing the effect of temperature, pH H2O2, and adsorbent. The results showed that the A-ATP@Fe3O4 achieves the highest removal rate of 99.6% under optimum conditions: 40 °C, pH = 3, H2O2 25 mM, and 0.1 g dosage of the composite. The dye removal procedure achieved adsorption and degradation equilibrium in 120 and 30 min, respectively, by following the same processes as the advanced oxidation approach. Catalytic activity, kinetics, and specified surface characteristics suggest that A-ATP@Fe3O4 is one of the most promising candidates for advanced oxidation-enrooted removal of organic dyes.

Carbon shell derived from bottle waste PET on α-Fe2O3/Fe3O4 heterostructure core as synergetic Fenton-like catalyst for degradation of antibiotics

In this work, two approaches to environmental sustainability have been followed including the synthesis of an efficient and easily recyclable catalyst for Fenton-like degradation of antibiotics from water, and the upcycling of waste polyethylene terephthalate (PET) into the value-added product through a feasible procedure. For this purpose, the Fe2O3/Fe3O4 mixture coated by the carbon layer derived from the bottle waste PET was synthesized for boosting the Fe3+/Fe2+ cycle in the Fenton-like reaction. The FeCl3 can act as a catalyst for graphitization process and also the precursor of metal oxide nanoparticles. The catalytic efficiency was evaluated for the degradation reaction of amoxicillin and azithromycin antibiotics. Complete conversion of amoxicillin and azithromycin (15 mg/L) was observed in the presence of 5 µL of H2O2, at pH=3 for 30 min. Also, the mineralization of amoxicillin and azithromycin was evaluated by TOC analysis, which was obtained as 77 and 89 %, respectively. The high activity of the catalyst can be attributed to the presence of a mixture of iron oxide nanoparticles for the catalysis of Fenton-like reactions and activation of H2O2, as well as the coating of nanoparticles with a carbon layer to stabilize and prevent metal leakage and contamination of the mixture. In addition, due to the good electrical conductivity of carbon layer, it can act as electron donors to enhance Fe3+ reduction.

Fabrication of N-doped graphitic carbon encapsulated Fe3C/Fe nanoparticles with dual-reaction centers for highly effective Fenton-like degradation of organic pollutants

The highly active and durable design of heterogeneous catalysts holds vital importance in the popularization of Fenton-like process for wastewater remediation. In this study, we successfully fabricated magnetic N-doped graphitic carbon (NC) encapsulated Fe3C/Fe nanoparticles, designated as Fe3C/Fe@NC-2.8, with a two-step pyrolysis method. We employed chitosan as a green precursor of NC, which is used as a heterogeneous Fenton-like catalyst to degrade refractory organic pollutants. Density functional theory (DFT) calculations revealed that the built-in electric field from the shell to core promoted electron transfer from NC to Fe3C/Fe, and thereby improved regeneration of Fe(II) and H2O2 activation. Because of the strong synergistic effects of the dual-reaction regions of Fe and Fe3C, as well as the core-shell structure advantages, the optimized Fe3C/Fe@NC rapidly degraded the typical refractory organic pollutants, and showed a much higher activity than the reference Fe2O3 and Fe3O4 samples. The total organic carbon removal efficiency of bisphenol A reached 70 % after reaction for 60 min. In addition, Fe3C/Fe@NC-2.8 possessed trace Fe leaching and satisfactory magnetically separable ability. This work provides mechanistic and practical perspectives for the development of advanced catalysts for recalcitrant pollutant treatment.