Fenton Degradation Research Articles

Impacts of ultrasound-assisted Fenton degradation and alkaline de-esterification on structural properties and biological effects of pectic polysaccharides from Tartary buckwheat leaves

Tartary buckwheat (Fagopyrum tataricum (L.) Gaertn) leaf has abundant rhamnogalacturonan-I enriched pectic polysaccharides, which exert various health-promoting effects. Nevertheless, the potential relationship between the chemical structure and the biological function of pectic polysaccharides from Tartary buckwheat leaves (TBP) remains unclear. Therefore, to bridge the gap between the chemical structure and the biological function of TBP, the impacts of ultrasound-assisted Fenton degradation (UFD) and mild alkaline de-esterification (MAD) on structural properties and biological effects of TBP were systematically studied. Compared with the native TBP (molecular mass, 9.537 × 104 Da), the molecular masses of degraded TBPs (TBP-MMW, 4.811 × 104 Da; TBP-LMW, 2.101 × 104 Da) were significantly reduced by the UFD modification, while their primary chemical structures were overall stable. Besides, compared with the native TBP (esterification degree, 22.73 %), the esterification degrees of de-esterified TBPs (TBP-MDE, 14.27 %; TBP-LDE, 6.59 %) were notably reduced by the MAD modification, while their primary chemical structures were also overall stable. Furthermore, the results revealed that both UFD and MAD modifications could significantly improve the antioxidant, antiglycation, and immunostimulatory effects of TBP. Indeed, TBP’s biological effects were negatively correlated to its molecular mass and esterification degree, while positively linked to its free uronic acids. The findings demonstrate that both UFD and MAD modifications are promising techniques for the structural modification of TBP, which can remarkedly promote its biological effects. Besides, the present results are conducive to better understanding TBP’s structure-bioactivity relationship.

Enhanced Heterogeneous Fenton Degradation of Organic Dyes by Bimetallic Zirconia-Based Catalysts.

The qualitative impact of pollutants on water quality is mainly related to their nature and their concentration, but in any case, they determine a strong impact on the involved ecosystems. In particular, refractory organic compounds represent a critical challenge, and several degradation processes have been studied and developed for their removal. Among them, heterogeneous Fenton treatment is a promising technology for wastewater and liquid waste remediation. Here, we have developed mono- and bimetallic formulations based on Co, Cu, Fe, and Mn, which were investigated for the degradation of three model organic dyes (methylene blue, rhodamine B, and malachite green). The treated samples were then analyzed by means of UV-vis spectrophotometry techniques. Bimetallic iron-based materials achieved almost complete degradation of all three model molecules in very short time. The Mn-Fe catalyst resulted in the best formulation with an almost complete degradation of methylene blue and malachite green at pH 5 in 5 min and of rhodamine B at pH 3 in 30 min. The results suggest that these formulations can be applied for the treatment of a broad range of liquid wastes comprising complex and variable organic pollutants. The investigated catalysts are extremely promising when compared to other systems reported in the literature.

Methylene blue treatment with zero-valent iron/pyrite/H2O2 system under static and continuous flow conditions: Reaction mechanism and toxicity evaluation

Laboratory batch and continuous flow studies, coupled with surface and toxicity analysis, were performed to evaluate methylene blue treatment by heterogeneous Fenton process using zero-valent iron (ZVI) and pyrite as co-catalyst. The use of pyrite in batch reactors significantly enhanced methylene blue treatment by the ZVI/H2O2 system because of improved iron redox cycling. The continuous-flow experiments revealed that the reactor performance increased in the order of: ZVI/H2O2 < pyrite/H2O2 < ZVI/pyrite/H2O2 under dynamic flow conditions. The methylene blue treatment by the ternary ZVI/pyrite/H2O2 system was described by an initial degradation of methylene blue with *OH radicals, followed by the adsorption and/or co-precipitation of degradation intermediates with some spherical particles. The surface analysis showed that these spherical particles formed, even at pH less than 4. The genotoxicity and cytotoxicity tests performed on mouse embryonic fibroblast (3 T3-L1) and human embryonic kidney (HEK293) cell lines showed that the Fenton treatment of methylene blue using the ZVI/pyrite/H2O2 system resulted in the formation of degradation species with much lower toxicity levels relative to methylene blue. Moreover, the Fenton degradation species of methylene blue significantly enhanced the metabolic activity of several bacterial strains, including E. coli ATCC 8739 and P. aeruginosa PAO1.

Metronidazole degradation mechanism by sono-photo-Fenton processes using a spinel ferrite cobalt on activated carbon catalyst

A heterogeneous catalyst was prepared by anchoring spinel cobalt ferrite nanoparticles on porous activated carbon (SCF@AC). The catalyst was tested to activate hydrogen peroxide (HP) in the Fenton degradation of metronidazole (MTZ). SCF nanoparticles were produced through the co-precipitation of iron and cobalt metal salts in an alkaline condition. Elemental mapping, physico-chemical, morphological, structural, and magnetic properties of the as-fabricated catalyst were analyzed utilizing EDX mapping, FESEM-EDS, TEM, BET, XRD, and VSM techniques. The porous structure of AC enhanced the catalytic activity of SCF by a significant decrease in the agglomeration of SCF nanoparticles. The effectiveness of SCF@AC in Fenton degradation improved substantially when UV light and ultrasound (US) irradiations were induced, most likely due to the strong synergistic effect between the catalyst and these irradiation sources. The photo-Fenton system was more efficient than the Fenton, sono-, and sono-photo-Fenton processes eliminating both MTZ and TOC. It was found that AC not only dispersed SCF nanoparticles and improved the stability of the catalyst, but also provided a high adsorption capacity of MTZ, resulting in a faster degradation. After 60 min of the photo-Fenton reaction, the elimination efficiencies of MTZ (30 mg L−1) and TOC were 97 and 42.1% under optimum operational conditions (pH = 3.0, HP = 4.0 mM, SCF@AC = 0.3 g L−1, and UV = 6 W). SCF@AC showed excellent stability with low leaching of metal ions during the reaction. Radical and non-radical (O2•–, HO•, and 1O2 species), alongside adsorption and photocatalysis mechanisms, were responsible for MTZ decontamination over the SCF@AC/HP/UV system. A comprehensive study on the HP activation mechanism and MTZ degradation pathway was obtained through scavenging tests. The findings demonstrate that SCF@AC is an effective, reusable, and environmentally sustainable catalyst for advanced oxidation processes that can effectively remove organic pollutants from wastewater. This study offers valuable insights into the feasibility of employing SCF@AC catalysts in Fenton-based processes for the degradation of MTZ.

The worthy green heterogeneous Fenton degradation process for removal of E102 in foodstuffs and industrial waste-waters using Cypress arizonica leaves based magnetic nanocomposite (CA-Fe3O4-MNc)

A new, green magnetic nanocomposite (MNc) was synthesized based on framework of Cypress arizonica (CA) leaves and then used as Fenton catalyst for removal of tartrazine (E102) in foodstuffs and industrial waste-waters. Characterization of the synthesized magnetic nanocomposite (CA-Fe3O4-MNc) was performed with IR, EDX, FESEM, XRD and pHpzc analyses. The average particle size and pHpzc of the CA-Fe3O4-MNc were determined to be 24.36 nm and 6.8, respectively. CA-Fe3O4-MNc was composed of C (15.08 %), Fe (51.86 %), O (31.80 %) and Ca (1.26 %) elements. The parameters effecting heterogeneous Fenton dye removal process including pH, catalyst amount, reaction time, H2O2 and initial dye concentrations were investigated to achieve the best removal efficiency for E102. Under optimal conditions, the matrix effect was investigated, the reusability of CA-Fe3O4-MNc was tested, degradation products and mechanism were elucidated, and green analytical procedure index (GAPI) and analytical eco-scale (AES) of the proposed Fenton degradation process were evaluated. E102 removal values were obtained between 93 and 99 % in the applications of some foodstuffs, water samples and artificial model dye solutions. Proposed heterogeneous Fenton removal process with using CA-Fe3O4-MNc catalyst exhibited quantitative removal efficiency for E102. E102 concentrations between 5 and 50 mg/L were removed successfully. It was observed that the synthesized CA-Fe3O4-MNc material could be used at least 5 times to obtain quantitative removal values. The percent removal efficiency value decreased to 93 after five uses. Defined GAPI parameters and calculated AES scores indicated that the proposed CA-Fe3O4-MNc based heterogeneous Fenton degradation process could be considered that a valuable green removal method.

Integrated AI-driven optimization of Fenton process for the treatment of antibiotic sulfamethoxazole: Insights into mechanistic approach

Antibiotics, as a class of environmental pollutants, pose a significant challenge due to their persistent nature and resistance to easy degradation. This study delves into modeling and optimizing conventional Fenton degradation of antibiotic sulfamethoxazole (SMX) and total organic carbon (TOC) under varying levels of H2O2, Fe2+ concentration, pH, and temperature using statistical and artificial intelligence techniques including Multiple Regression Analysis (MRA), Support Vector Regression (SVR) and Artificial Neural Network (ANN). In statistical metrics, the ANN model demonstrated superior predictive accuracy compared to its counterparts, with lowest RMSE values of 0.986 and 1.173 for SMX and TOC removal, respectively. Sensitivity showcased H2O2/Fe2+ ratio, time and pH as pivotal for SMX degradation, while in simultaneous SMX and TOC reduction, fine tuning the time, pH, and temperature was essential. Leveraging a Hybrid Genetic Algorithm-Desirability Optimization approach, the trained ANN model revealed an optimal desirability of 0.941 out of 1000 solutions which yielded a 91.18% SMX degradation and 87.90% TOC removal under following specific conditions: treatment time of 48.5 min, Fe2+: 7.05 mg L−1, H2O2: 128.82 mg L−1, pH: 5.1, initial SMX: 97.6 mg L−1, and a temperature: 29.8 °C. LC/MS analysis reveals multiple intermediates with higher m/z (242, 270 and 288) and lower m/z (98, 108, 156 and 173) values identified, however no aliphatic hydrocarbon was isolated, because of the low mineralization performance of Fenton process. Furthermore, some inorganic fragments like NH4+ and NO3− were also determined in solution. This comprehensive research enriches AI modeling for intricate Fenton-based contaminant degradation, advancing sustainable antibiotic removal strategies.

Urchin-like CO2-responsive magnetic microspheres for highly efficient organic dye removal

CO2-responsive materials have emerged as promising adsorbents for the remediation of refractory organic dyes-contaminated wastewater without the formation of byproducts or causing secondary pollution. However, realizing the simultaneous adsorption−separation or complete removal of both anionic and cationic dyes, as well as achieving deeper insights into their adsorption mechanism, still remains a challenge for most reported CO2-responsive materials. Herein, a novel type of urchin-like CO2-responsive Fe3O4 microspheres (U-Fe3O4 @P) has been successfully fabricated to enable ultrafast, selective, and reversible adsorption of anionic dyes by utilizing CO2 as a triggering gas. Meanwhile, the CO2-responsive U-Fe3O4 @P microspheres exhibit the capability to initiate Fenton degradation of non-adsorbable cationic dyes. Our findings reveal exceptionally rapid adsorption equilibrium, achieved within a mere 5 min, and an outstanding maximum adsorption capacity of 561.2 mg g−1 for anionic dye methyl orange upon CO2 stimulation. Moreover, 99.8% of cationic dye methylene blue can be effectively degraded through the Fenton reaction. Furthermore, the long-term unresolved interaction mechanism of organic dyes with CO2-responsive materials is deciphered through a comprehensive experimental and theoretical study by density functional theory. This work provides a novel paradigm and guidance for designing next-generation eco-friendly CO2-responsive materials for highly efficient purification of complex dye-contaminated wastewater in environmental engineering.

Three-dimensional electrochemical Fenton degradation of CIP by doping Ce and Cu in Jacaranda shell base as particle electrodes

Currently, ciprofloxacin (CIP) in water environments has attracted wide attention. In order to degrade CIP by electrocatalysis, it is very important to develop catalysts with high catalytic activity as particle electrodes. In this study, Jacaranda shell was made into biochar (BC) by calcination, Ce and Cu modified BC (Ce-Cu/BC) was prepared by a simple impregnation and calcination method as a particle electrode in a three-dimensional electro-Fenton (3D/EF) system to degrade CIP. Characterization of the Ce-Cu/BC particle electrodes was conducted using SEM, XRD, and XPS, revealing the porous structure of the calcined jacaranda shell base, confirming successful loading of Ce and Cu. Optimal operating conditions for CIP removal were determined to be 4 g/100 mL particle electrodes dosage, initial pH of 5, 8 V voltage, and 2 mM Fe2+ concentration, resulting in a maximum CIP removal rate of 84.97% with an energy consumption of 1.32 W•h. Stability tests demonstrated the robustness of Ce-Cu/BC, while comparative tests and radical extinction experiments highlighted the high electrocatalytic activity of the 3D/EF system, primarily attributed to the indirect oxidation of •OH, an active substance generated within the system LC-MS and UV full-band scanning analyses were employed to propose potential CIP degradation pathways.

Development of an adsorption-enhanced heterogeneous Fenton process for abatement of natural organic matter by kaolin-supported phytogenic nanoscale zero-valent iron

Abstract Natural organic matter (NOM) serves as a precursor for the formation of carcinogenic disinfection by-products when not adequately removed by conventional water treatment processes. The degradation of NOM by heterogeneous Fenton processes is particularly attractive because it results in prospects of zero sludge discharge. This work reports on NOM degradation and adsorption via the heterogeneous Fenton process using phytogenic zero-valent iron nanoparticles (nZVI) synthesised from green tea extract (Camellia sinensis) and supported on kaolin (fK-nZVI). The synthesised material was characterised using scanning electron microscopy (SEM), Fourier-transform infrared spectroscopy (FTIR) and Brunauer-Emmett-Teller (BET) analysis. Morphological analysis of SEM images and BET values revealed an increase in the surface area from 11.64 m2 · g−1 for kaolin to 27.07 m2 · g−1 for the kaolin-supported nZVI (K-nZVI), thus presenting an ideal modification for effective adsorption. Fenton process parameters were optimised, that is, H2O2 concentration (5 mM) and pH (4.5). At equilibrium, the adsorption by the fK-nZVI system was 0.127 mg · g−1, a value higher than reported in other adsorption systems at equivalent adsorbent dosage and NOM concentration. The promising results obtained in this study indicate heterogeneous Fenton degradation and adsorption can be a viable and effective method for NOM removal from aqueous media.

Transforming waste brake pads from automobiles into Nano-Catalyst: Synergistic Fe-C-Cu triple sites for efficient fenton-like oxidation of organic pollutants

The arbitrary disposal of used brake pads from motor vehicles has resulted in severe heavy metal pollution and resource wastage, highlighting the urgent need to explore the significant untapped potential of these discarded materials. In this study, The in-situ growth of highly dispersed Fe2O3 nanocrystals was achieved by simple oxidation annealing of brake pad debris(BPD). Interestingly, Cu remained unoxidized and acted as a “valence state transformation bridge of Fe2O3” to construct the “triple Fe-C-Cu sites”. The Fenton degradation experiment of pollutants was conducted under constant temperature conditions at 40 °C, a stirring rate of 1300 rpm, a pH value of 3, a catalyst dosage of 0.5 g/L, pollutant dosage ranging from 50 to 400 mg/L, and H2O2 dosage of 0.25 g/L. Experimental results showed that BPD treated at 300 °C for 2 h exhibited optimal Fenton-like oxidation activity, achieving rapid degradation of over 90 % of refractory antibiotics, such as tetracycline and ciprofloxacin, in organic wastewater within 10 min. This remarkable performance was mainly attributed to the synergistic effect of “Fe-C-Cu triple sites”, where the electron-donating role of C in the Fe-C and Cu-C interfaces facilitated the conversion of the Fe(III) to Fe(II) and Cu(II) to Cu(I). In addition, the ability of Cu2+ to accept electrons at the Fe-Cu interface promoted the transition from Fe (II) to Fe (III). This “balance of electron gain and loss” accelerated the interfacial electron transfer and the recycle of dual Fenton sites, Fe(II)/Fe(III) and Cu(I)/Cu(II), to generate more ·OH from H2O2. Therefore, this strategy of functionalizing BPD as Fenton-like catalysts without the addition of external Fe provides intriguing prospects for understanding the construction of Fe-based Fenton catalysts and resource utilization of Fe-containing solid waste materials.

In situ use of photocatalytically produced H2O2 for Fenton degradation of organic pollutants

Steps 1 to 4 illustrate the mechanism for the photocatalytic production of H2O2 and its in situ utilization for Fenton-like degradation of organic pollutants.

The abundant oxygen vacancy on CuInS2/BiOBr composite catalyst cooperated with the double Fenton system to perform efficient heterogeneous Fenton degradation of levofloxacin

The abundant oxygen vacancy on CuInS2/BiOBr composite catalyst cooperated with the double Fenton system to perform efficient heterogeneous Fenton degradation of levofloxacin

Synergistic adsorption-Fenton degradation of organic pollutants by MIL-88B/montmorillonite and cellulose nanocrystals functionalized gelatin composite aerogels

In this work, MIL-88B loaded montmorillonite (MMT) and cellulose nanocrystals (CNC) were incorporated into gelatin (G) aerogel to yield a multifunctional and reinforced bio-aerogel, named as MMCG aerogel, for removing organic pollutants by synergistic adsorption and Fenton degradation. As expected, the MMCG aerogels exhibited highly efficient adsorption capacity for charged pollutants. The adsorption process of methyl blue (MB) followed well with Langmuir isotherm, while tetracycline hydrochloride (TCH) and methylene blue (MEB) could be better fitted by Freundlich isotherm. The adsorption kinetics were accurately described by the pseudo-second-order kinetic model. Thermodynamic experiments revealed that the adsorption process was endothermic and spontaneous. The maximum adsorption capacities for MB, MEB and TCH were 1494.47 mg/g, 952.26 mg/g and 701.82 mg/g, respectively. Electrostatic interactions, hydrogen bonds and π-π interactions may be responsible for the adsorption mechanism. Most importantly, it exhibited better removal performance for all organic contaminants with or without charged states by triggering the Fenton reaction with the addition of H2O2. For the non-adsorbed bisphenol A (BPA) with uncharged state, the removal efficiency after Fenton degradation significantly increased from 4.73 % to 86.13 %. Additionally, it had excellent recyclability. Therefore, the MMCG aerogel could be recognized as a promising material for wastewater treatment.

Magnetite nanoparticles decorated on cellulose aerogel for p-nitrophenol Fenton degradation: Effects of the active phase loading, cross-linker agent and preparation method

Magnetite nanoparticles (Fe3O4 NPs) are among the most effective Fenton-Like heterogeneous catalysts for degrading environmental contaminants. However, Fe3O4 NPs aggregate easily and have poor dispersion stability because of their magnetic properties, which seriously decrease their catalytic efficiency. In this study, a novel environmentally friendly method for synthesising Fe3O4@CA was proposed. Fe3O4 NPs were immobilized on the 3D cellulose aerogels (CAs) in order to augment the degradation efficiency of p-nitrophenol (PNP) treatment and make the separation of the catalyst accessible by vacuum filtration method. Besides, CAs were fabricated from a cellulose source extracted from water hyacinth by using different cross-linking agents, such as kymene (KM) and polyvinyl alcohol–glutaraldehyde system (PVA–GA), and other drying methods, including vacuum thermal drying and freeze drying, were evaluated in the synthesis process. As-synthesized samples were analysed by various methods, including Powder X-ray diffraction, Fourier transform infrared spectroscopy, field emission scanning electron microscopy, energy dispersive X-ray analysis and Brunauer–Emmett–Teller. Then, using ultraviolet–visible spectroscopy, the difference in the degradability of PNP of the obtained material samples was also investigated to determine their potential applications. Results highlighted that the Fe3O4-3@CA-KF catalyst with an Fe3O4 loading of 0.40 g/gCA used KM as a cross-linker and the freeze-drying method demonstrated the highest PNP removal efficiency (92.5 %) in all Fe3O4@CA samples with a H2O2 content of 5 g/L. The degradation kinetics and well-fitted pseudo-first-order model were investigated. Notably, after five successive PNP degradation experiments, this catalyst retained ∼80 % of the ability to degrade PNP, indicating its outstanding reusability. In environmental remediation, this study provides valuable insights into the development of simply separated and high-efficiency catalysts for heterogeneous catalytic reactions.

Enriched adsorption and photocatalytic Fenton catalytic degradation of organic pollutants by CuBi2O4 loaded non-metallic modified graphene composite hydrogels

Adsorption and advanced oxidation technology are important means to remove organic pollutants, and the combination of adsorption and catalytic degradation to construct a multi-field coupled system can realize valid adsorption and degradation of organic contaminants. In this paper, CuBi2O4 supported by a nonmetallic element-modified graphene hydrogel composite structure CuBi2O4/X-rGH (X = N, P, S, B) was synthesized and applied to the efficient removal of organic pollutants. We found that the doping of nonmetallic elements enhances the graphene conjugated large π-bond system, which not only improves the adsorption performance of pollutants but also increases the graphene conductivity and builds more carrier transport channels, which is beneficial to the photocatalytic Fenton synergistic degradation activity. Among them, CuBi2O4/P-rGH could achieve 90 % degradation of phenol (50 ppm) after 20 min of turning on the light, which was nearly 2 times more than the degradation activity of CuBi2O4/rGH. Electron paramagnetic resonance (EPR) and quenching experiments proved that ·OH was the main active species in the synergistic degradation process, and the mechanism of adsorption of nonmetallic modified graphene hydrogel hybrid catalysts and in situ photocatalytic Fenton degradation of pollutants was proposed.

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.

Adsorption and heterogenous Fenton-like reactivity of NH2-MIL-88B towards toxic dyes removal

Organic pollutants especially those with high toxicity and non-degradability are severely threatening environmental and human beings. Compared with traditional methods, advanced oxidation methods such as Fenton degradation have gained much attention thanks to their distinct advantages. Herein, NH2-MIL-88B was fabricated via solvothermal method and used in rhodamine b (RhB) removal from aqueous solution. We emphasized on activation effect on structure and RhB removal ability change. Different from other reports, it is found that activation didn’t induce the valence state change of Fe in the sample. But the adsorption ability was significantly increased, which synergistically led to the enhanced heterogeneous Fenton-like degradability. The prominently increased adsorption was ascribed to the increased surface area induced by activation. Synergistic effect of enhanced adsorption and heterogeneous Fenton-like degradation enables NH2-MIL-88B with optimized parameters to remove RhB totally with initial concentration of 50 mg/L in 60 mins. RhB adsorption on NH2-MIL-88B followed Langmuir adsorption isotherm and the adsorption behavior abided by pseudo-second-order kinetics. It was proposed that activation would directly increase adsorption and indirectly increase heterogeneous Fenton-like degradation. This synergistic effect endow NH2-MIL-88B with great performance. Our research here could provide clues for exploiting strategies to improve ability of existed MIL(Fe)-type heterogenous Fenton-like catalyst and fabricating novel products.

Synthesis of plant-based biogenic jarosite nanoparticles using Azadirachta indica and Eucalyptus gunni leaf extracts and its application in Fenton degradation of dicamba

Bio-jarosite, an iron mineral synthesized biologically using bacteria, is a substitute for iron catalysts in the Fenton oxidation of organic pollutants. Iron nanocatalysts have been widely used as Fenton catalysts because they have a larger surface area than ordinary catalysts, are highly recyclable, and can be treated efficiently. This study aimed to explore the catalytic properties of bio-jarosite iron nanoparticles synthesized with green methods using two distinct plant species: Azadirachta indica and Eucalyptus gunni. The focus was on the degradation of dicamba via Fenton oxidation. The synthesized nanoparticles exhibited different particle size, shape, surface area, and chemical composition characteristics. Both particles were effective in removing dicamba, with removal efficiencies of 96.8% for A. indica bio-jarosite iron nanoparticles (ABFeNPs) and 93.0% for E. gunni bio-jarosite iron nanoparticles (EBFeNPs) within 120 min of treatment. Increasing the catalyst dosage by 0.1 g/L resulted in 7.6% and 43.0% increases in the dicamba removal efficiency for EBFeNPs and ABFeNPs with rate constants of 0.025 min−1 and 0.023 min−1, respectively, confirming their catalytic roles. Additionally, the high efficiency of both catalysts was demonstrated through five consecutive cycles of linear pseudo-first-order Fenton oxidation reactions.

Fe-pillared montmorillonite functionalized chitosan/gelatin foams for efficient removal of organic pollutants by integration of adsorption and Fenton degradation

A Fe-pillared montmorillonite (Fe-MMT) functionalized bio-based foam (Fe-MMT@CS/G) was developed by using chitosan (CS) and gelatin (G) as the matrix for high-efficiency elimination of organic pollutants through the integration of adsorption and Fenton degradation. The results showed that the mechanical properties of as-obtained foam were strengthened by the addition of certain amounts of Fe-MMT. Interestingly, Fe-MMT@CS/G displayed efficient adsorption ability for charged pollutants under a wide range of pH. The adsorption processes of methyl blue (MB), methylene blue (MEB) and tetracycline hydrochloride (TCH) on Fe-MMT@CS/G were well described by the Freundlich isotherm model and pseudo-second-order kinetic model. The maximum adsorption capacities were 2208.24 mg/g for MB, 1167.52 mg/g for MEB, and 806.31 mg/g for TCH. Electrostatic interactions, hydrogen bonding and van der Waals forces probably involved the adsorption process. As expected, this foam could exhibit better removal properties toward both charged and uncharged organic pollutants through the addition of H2O2 to trigger the Fenton degradation reaction. For non-adsorbable and uncharged bisphenol A (BPA), the removal efficiency was dramatically increased from 1.20 % to 92.77 % after Fenton degradation. Additionally, it presented outstanding recyclability. These results suggest that Fe-MMT@CS/G foam is a sustainable and efficient green material for the alleviation of water pollution.

Fe‐doped MoS2@AuNPs Grown on Carbon Cloth for Efficient SERS Detection and Photo/photo‐Fenton Degradation of Fungicides

AbstractA composite CC/Fe−MoS2@Au composed of gold nanoparticles in‐situ grown on Fe‐doped MoS2 anchored on carbon cloth (CC) was prepared for SERS detection and photo/photo‐Fenton degradation of fungi pesticides. Flower‐like MoS2 grown on CC provides large surface area for in‐situ reduction and immobilization of AuNPs, generating high SERS enhancement effect. Fe‐doping improves MoS2’s SERS activity and photocatalysis and endows the composite with Fenton degradation ability due to the coexistence of Fe3+/Fe2+ confirmed by XPS. Owing to their synergy, the CC/Fe−MoS2@Au can achieve the SERS detection of fungicide crystal violet (CV) and malachite green (MG) with detection limits of 0.1 nM and 10 nM, respectively. The CC endows it flexibility for fungicide sensing on irregular surface, such as fish skin with a LOD of 10−7 M for MG. The composite displayed multimode degradation ability for fungicides: 70 % of 10−5 M CV could be degraded after 75 min photocatalytic degradation by CC/Fe−MoS2@Au under natural light, while it increases to 85 % in the presence of H2O2 through a photo‐Fenton reaction. The synergy mechanism of these components for fungicide degradation were discussed. Such flexible multifunctional composite has great value in SERS analysis, environmental monitoring and remediation.