Iron Precursor Research Articles

Tailoring the Wettability of Bacterial Cellulose Magnetobots via the Assembly of In Situ Synthesized and Surfactant-Coated Magnetic Nanoparticles.

This study showcases the possibility of tailoring the wettability of magnetic bacterial cellulose (m-BC) composites by the combined effect of in situ synthesized magnetic nanoparticles (MNPs) distribution and simultaneous oleic acid (OA) coating within the BC matrix. This combined effect of MNPs and OA resulted in m-BC composites exhibiting solvent-dependent and time-dependent surface-wetting behavior, which was not observed in either individual cases of BC that have been modified with OA or BC that has MNPs adsorbed on its fibers. This tailored wettability in m-BCs was achieved via varying the concentrations of iron precursors, which governed the arrangement and morphology of MNPs (uniformly or clustered) on the BC membrane, although the same fraction of MNPs was observed in both the m-BCs. Finally, we have achieved delayed water absorption in m-BC_x (synthesized in a comparatively lower precursor concentration) and no absorption of water in m-BC_4x (synthesized in a 4-times-higher precursor concentration). The m-BC_4x composite maintained its hydrophobic characteristics in diverse environments, ranging from highly acidic conditions (pH 1.2) to physiological environments at pH 4, 5.5, and 7.4. The MNP agglomerates on the BC nanofibers in the m-BC_4x composite were found to be instrumental in attaining a stable cyclic absorption performance with structural integrity. Additionally, the magnetic-inducing heat generation efficiency of the m-BCs can be extended for evaporating low-boiling-point solvents. The present study expands the frontiers of BC-based magnetic composites by emphasizing the assembly of surfactant-coated magnetic nanostructures in their responsiveness to polar/nonpolar liquids with stable performance even in complex scenarios.

Synthesis and Magnetic Properties of Spherical Maghemite Nanoparticles with Tunable Size and Surface Chemistry.

We report the synthesis of uniform populations of spherical maghemite nanoparticles by thermal decomposition of iron precursors with tunable diameters centered at 3.3, 7.5, and 12.0 nm and tunable surface chemistry. The three stabilizing ligands were fatty acids with three different alkyl chain lengths (18, 12, and 8 carbon atoms). The unprecedented accurate control of the surface chemistry is made possible by the use of three types of iron complexes, that is, iron oleate (C18), iron dodecanoate (C12), and iron octanoate (C8), associated with fatty acid ligands having the same alkyl chain length, that is, oleic acid (C18), dodecanoic acid (C12), and octanoic acid (C8). Since the thermal decomposition of the iron precursor varies with the chain length, no general rules can be applied to control the nanoparticle size, but optimal synthesis conditions have been investigated to induce the growth of nanoparticles with three different surface chemistries, keeping the diameters centered at 3.3, 7.5, and 12.0 nm. Finally, structural characterization of the nine populations of maghemite nanoparticles was performed by transmission electron microscopy and X-ray diffraction, and magnetic properties were determined by using SQUID magnetometry.

Comprehensive Evaluation of Process Parameters in the Green Synthesis of Iron Oxide Nanoparticles Using Moringa olifera extract.

This study investigates the green synthesis of iron oxide nanoparticles using Moringa olifera ethanolic extract and evaluates the impact of various process parameters on their physicochemical characteristics. The parameters examined include synthesis time, temperature, pH, stirring speed (RPM), and the ratio of extract to iron precursors. The findings reveal that a lower proportion of the extract increases the entrapment efficiency of the nanoparticles. Specifically, batch ME3 (3:1 ratio) produced the smallest nanoparticles at 117.8 nm, with a drug release of 75.54% and the highest entrapment efficiency at 60.28%. Extending the synthesis time to three hours in batch TM3 resulted in a drug release of 74.23% and a particle size of 116.3 nm. Batch TEM1, synthesized at 70°C, showed the highest entrapment efficiency and a favorable drug release profile of 71.09%, with the smallest particle size of 105.24 nm, suggesting that higher synthesis temperatures favor smaller particle sizes. Adjusting the pH to 10 in batch PM3 achieved a drug release efficiency of 76.02%. Batch RM5, synthesized with a stirring speed of 750 RPM, demonstrated a particle size of 95.7 nm and a drug release of 78.26%, indicating that higher stirring rates produce smaller nanoparticles and enhance drug release. These results highlight the significance of optimizing synthesis conditions to produce nanoparticles with desired properties. The use of M. olifera extract as a sustainable reducing and stabilizing agent presents an environmentally friendly approach to nanotechnology. This method has potential applications in drug delivery systems and various other industries, emphasizing the importance of green synthesis in creating sustainable and efficient nanomaterials.

Facile microwave synthesis of various-shaped magnetite/ reduced graphene oxide heterostructures and their magnetization properties

Heterostructures of magnetite (Fe3O4) nanoparticles and reduced graphene oxide (RGO) sheets are very common composite materials for different applications such as catalysis, energy storage, and biomedicine. Developing methods for the facile control of the size and shape of both freestanding Fe3O4 nanoparticles and those anchored onto RGO sheets is in demand. Herein, we report on the rapid and facile microwave synthesis (MWS) of Fe3O4 nanoparticles and Fe3O4/RGO with various sizes and shapes using the oleylamine (OAm)/oleic acid (OAc) ligand pair. The solvothermal synthesis using microwave irradiation (MWI) resulted in the concurrent conversion of graphene oxide (GO) into RGO and the in-situ formation of various-shaped Fe3O4 on RGO sheets. Freestanding Fe3O4 nanoparticles of various shapes were prepared using MWS for comparison. The morphological, structural, and surface properties of the samples were studied using different characterization techniques. The magnetization properties of the prepared samples were determined using a vibrating sample magnetometer. Various-shaped standalone and RGO-supported Fe3O4 nanoparticles including nanospheres, nanocubes, and nanotriangles were synthesized via MWI at 1000 W for 20 min by changing the ratios of the iron precursor and the OAm/OAc ligand pair. Interestingly, the MWI using OAm/OAc ligand pair of a molar ratio of 3:4 resulted in the in-situ formation of large hexagonal Fe3O4/RGO. The X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) results confirm the crystallinity and spinel structure of the prepared Fe3O4 samples and prove the concurrent conversion of GO into RGO with assemblies of Fe3O4 nanoparticles. The magnetization measurements further emphasized the role of size and shape in affecting the magnetic properties of Fe3O4 and Fe3O4/RGO heterostructures. The results identify the qualities of the prepared samples and prove the MWS as a facile one-pot method for the preparation of Fe3O4 and Fe3O4/RGO heterostructures.

Methyl esters production from Waste Cooking Oil catalysed by iron oxides supported on CaO: Cost and environmental impacts

It was the objective of this work, to assess the midpoint environmental impacts of the catalyst synthesis stage and biodiesel production from waste cooking oil (WCO) as feedstock, depending on the catalyst source, i.e. Fe2O3 or Fe(NO3)3⋅9H2O, lime or waste clam shells, to produce the applied bifunctional catalyst based on iron and CaO. The cost of biodiesel production depending on the catalyst was also established. In the catalyst synthesis stage, the use of clam shells contributed the most to the midpoint environmental categories, mainly terrestrial ecotoxicity, freshwater ecotoxicity, marine ecotoxicity and human non-carcinogenic toxicity. In the stage of biodiesel production (esterification-transesterification reaction), the scenario contributing the lowest (20.95–22.16 %) to the midpoint environmental impacts is when using Fe(NO3)3·9H2O and CaO as iron and lime precursors, respectively. Using waste clam shells increases the environmental impacts. Regarding costs, the clam shells lead to the most expensive process ($0.08 USD/MJ). The source of energy to conduct the biodiesel production was also assessed and it was found that the use of wind turbines leads to the lowest global warming potential (GWP), 11.6 g CO2 eq·MJ-1, with the catalyst prepared with the iron salt and with the CaO from lime. The presented results were obtained with the commercial software SimaPro® version 9.6 PhD. For the inventory, experimental data obtained at laboratory scale and previously published were used.It was concluded that based on environmental impacts and costs, it is recommended to use lime instead of clam shells waste as precursor of CaO and Fe(NO3)3·9H2O as precursor of iron.

Polyvinylpyrrolidone mediated electrospun ZnO-ZnFe2O4 composite nanofibers for removing malachite green from water

This study explores the application of ZnO-ZnFe2O4 composite nanofibers for the adsorption of Malachite Green (MG) dye from water. The composite nanofibers were fabricated using simple polyvinylpyrrolidone (PVP) mediated electrospinning method by changing zinc and iron precursor weight ratio named as Zn–Fe (1-1), Zn–Fe (2–1) and Zn–Fe (1–2). The diameter of 1D nanofibers was found to be 40–60 nm. The formation of hexagonal wurtzite structure of ZnO and cubic spinel structure of ZnFe2O4 was confirmed by XRD and HRTEM analysis. The effects of various parameters such as pH, contact time and initial concentration on the adsorption process were investigated. The Zn–Fe (1-1) nanofibers showed higher adsorption efficiency than other two. The adsorption results demonstrated excellent adsorption performance, with a maximum adsorption capacity of 146.77 mg/g at pH = 7 for Zn–Fe (1-1). Furthermore, the adsorption kinetics and isotherms were analyzed to understand the adsorption mechanism and equilibrium behaviour. It was found that the nanofibers material can be recycled and reused up to five cycles.

Improving the synthesis of heterogeneous catalysts by gliding arc plasma using the “no-cooling system”

Glidarc plasma (GP) is a promising method for preparing heterogeneous catalysts due to its mild conditions and short processing time. This technique has been used to synthesize various catalysts like FeOx and MnOx. Adding a post-discharge (PD) step during synthesis has been shown to impart valuable new properties, such as phase transformation, increased specific surface area, and enhanced catalytic activity. Knowing that the PD step mostly impacts the plasma-synthesized solids maturation and can be accelerated if heat is introduced into the system, we now contemplate the possibility of accelerating the GP catalysts synthesis by allowing the solution to be heated by the energy spontaneously provided by the plasma without the necessity to add a PD. To challenge this approach, we subjected FeSO4 and SnSO4 precursors to plasma exposure without employing the cooling system usually integrated in the GP set-up and compared the resulting solids with those obtained via conventional GP synthesis involving a PD step. The findings show that for iron precursors, the absence of cooling accelerates the formation of non-catalytically active phases and causes particle agglomeration, which is undesirable. However, for tin precursors, the absence of a cooling system introduces features that further improve the catalytic activity of the solids. Precisely, tin oxide phases developed better than other less-catalytically active ones without affecting the textural properties of the solid. This suggests that in some cases, eliminating the PD step can simplify the GP catalyst synthesis process and reduce its environmental and economic impact.

Photolytic decomposition of PFOS by electrospun nanofiber composites of Fe(III)/PVDF Under UV-C light

Per- and polyfluoro alkyl substances (PFAS) are emerging pollutants that have contaminated various water streams of the world. Besides polluting the environment, it is related to several human diseases, including cancer. Various methods have been proposed to remove PFAS from water streams including, photocatalytic or photolytic decomposition of PFAS which decomposes PFAS in a quasi-perpetual fashion and does not generate secondary pollution. In this work, perfluoroctane sulfonic acid (PFOS) is used as a model PFAS to study its photolytic decomposition by nanofiber composites (NFC) of Fe (III) and polyvinylidene fluoride (PVDF) under ultraviolet (UV)-C light. The nanofiber composite was fabricated using an electrospinning technique with PVDF and iron precursor on the conductive surface of indium tin oxide (ITO) coated polyethylene terephthalate (PET) film. The composite was characterized with SEM-EDX, AFM, XRD, and TGA. It was found that a significant amount, 70 % of aqueous PFOS solution is decomposed by the composites in the presence of traces of hydrogen peroxide and UV-C light. The kinetics of PFOS degradation was fit with pseudo-first order rate constant of 0.056 hr−1. It is proposed that PFOS binds with Fe(III) to form an unstable complex that is decomposed under UV-C light and Fe(III) is reduced Fe(II). Hydrogen peroxide provides the simultaneous benefits of further decomposing the PFOS complex and regenerating Fe(III). The overall results suggest that this nanofiber composite can be used for the photolytic decomposition of PFOS. It is also revealed that two composite mats showed the optimal performance and the increase in concentration of hydrogen peroxide increased the degradation of PFOS monotonically.

Enhanced properties of TiO2 nanotubes through α-Fe2O3 surface decoration: Synthesis, characterization, and performance evaluation

Electrochemical anodization, under a constant voltage of 45 V and for 15, 30, and 45 min, was performed to fabricate highly ordered TiO2 nanotubes. Depending on the processing paramters, the diameter of the TiO2 nanotubes was found to be around 95 ± 6 nm, while the thickness of TNT layer exhibited a change with anodizing time, varying from 1 to 4 μm. Subsequent to the anodization α-Fe2O3/TiO2 heterogeneous structure was created by the spin coating of iron precursor based solutions on TiO2 nanotubes. X-ray diffraction (XRD) and scanning electron microscopy (SEM) analysis were utilized to ascertain the phase structure and morphology of TiO2 nanotubes. The change of optical band gap values depending on the processing parameters was calculated using UV–Vis spectrophotometer data. The photocatalytic performances of the samples, namely the degradation rates and kinetics, were evaluated by examining the photodegradation of methylene blue (MB). The (TC15) sample, obtained by anodizing for 15 min and decorated with α-Fe2O3, exhibited the highest photocatalytic activity, with a degradation efficiency of 70 % at the end of 7 h of light exposure. On the other hand, the inhibition percentages of bacterial growth were examined and it was seen that the TC30 sample with the highest value was 88.89 % for E.coli bacteria and 70.57 % for S.aureus. To assess the mechanism of antimicrobial activity, ROS (Reactive Oxygen Species) Analysis were perfomed on T30 and TC30 groups and the ROS amount of TC30 was higher than T30. According to the results of the L929 mouse fibroblast cytotoxicity experiment with indirect contact according to ISO 10993-5 standards, all samples showed a successful performance in terms of cell viability. The cell viability of TC15 was higher in comparison to the control group.

Activating Fenton-like reaction by hydrochars containing persistent free radicals derived from various pomelo peel components

To reveal the influence of the diversity of precursors on the formation of environmental persistent free radicals (EPFRs), pomelo peel (PP) and its physically divided portion, pomelo cuticle (PC), and white fiber (WF) were used as precursors to prepare six hydrochars: PPH-Fe, PCH-Fe, WFH-Fe, PPH, PCH, and WFH with and without Fe(III) addition during hydrothermal carbonization (HTC). PPH-Fe and WFH-Fe had higher EPFRs content (9.11 × 1018 and 8.25 × 1018 spins·g−1) compared to PPH and WFH (3.33 × 1018 and 2.96 × 1018 spins·g−1), indicating that iron-doping favored EPFRs formation. However, PCH-Fe had lower EPFRs content (2.78 × 1018 spins·g−1) than PCH (7.95 × 1018 spins·g−1), possibly due to excessive iron leading to the consumption of the generated EPFRs. For another reason, the required Fe(III) amount for EPFRs formation might vary among different precursors. PC has a lower concentration of phenolic compounds but 68–97% fatty acids, while WF and PP are rich in cellulose and lignin. In the Fenton-like reaction, oxygen-centered radicals of hydrochar played a significant role in activating H2O2 and efficiently degrading bisphenol A (BPA). Mechanisms of reactive oxygen species (ROS) generation in hydrochar/H2O2 system were proposed. EPFRs on hydrochar activate H2O2 via electron transfer, creating ·OH and 1O2, leading to BPA degradation. More importantly, the embedded EPFRs on the hydrochar's inner surface contributed to the prolonged Fenton-like reactivity of PPH-Fe stored for 45 days. This study demonstrates that by optimizing precursor selection and iron doping, hydrochars can be engineered to maximize their EPFRs content and reactivity, providing a cost-effective solution for the degradation of hazardous pollutants.Graphical abstract

Sol–gel synthesis of iron titanates for the photocatalytic degradation of cyanide

Iron titanate mixed metal oxides were synthesized by the sol–gel method through four different routes. The effect of (i) the solvent of iron precursor, (ii) the addition of the chelating agent to the titanium or iron solution and (iii) the molar ratio between the chelating agent and the titanium or iron precursor over the overall percentage of obtained iron titanates was evaluated. Fourier-transform infrared spectroscopy (FTIR) and UV–Vis spectroscopy (UV–Vis) performed on the reaction medium evidenced the formation of acetate complexes of titanium (IV) or iron (III) during the different routes. X-ray diffraction (XRD) patterns of the obtained materials showed the formation of ilmenite (FeTiO3), pseudorutile (Fe2Ti3O9) and pseudobrookite (Fe2TiO5) in different proportions, as well as hematite (Fe2O3), rutile [TiO2 (R)] and anatase [TiO2 (A)]. The materials with the highest content of iron titanates obtained in each route were characterized and evaluated in the photocatalytic degradation of cyanide using visible light irradiation. UV–Vis Diffuse Reflectance Spectroscopy (UV–Vis DRS) showed that the samples exhibited energy bandgap values between 2.31 and 2.90 eV, which agrees with the values reported for iron titanates and evidence the possible activation of the materials under visible light. Scanning electron microscopy (SEM) and nitrogen physisorption results showed that the synthesized materials exhibited nanometric particle size and lower surface area (36.7 ± 4.8 m2·g-1) than TiO2 Degussa P-25 (72–155 m2·g-1). The photocatalytic performance of the synthesized materials toward oxidation of CN− exceeded by 56% the activity of pure TiO2. The content of iron titanates in the synthesized materials was found to be the variable with the greatest influence on the photodegradation of cyanide. In addition, an inversely proportional relationship between the pseudorutile content of the materials and their photocatalytic activity was observed.

A Strategy for Anode Recovery and Upgrading by In Situ Growth of Iron-Based Oxides on Microwave-Puffed Graphite.

Faced with the increasing volume of retired lithium-ion batteries (LIBs), recycling and reusing the spent graphite (SG) is of great significance for resource sustainability. Here, a facile method for transforming the SG into a carbon framework as well as loading Fe2O3 to form a composite anode with a sandwich structure is proposed. Taking advantage of the fact that the layer spacing of the spent graphite naturally expands, impurities and intercalants are eliminated through microwave thermal shock to produce microwave-puffed graphite (MPG) with a distinct three-dimensional structure. Based on the mechanism of microwave-induced gasification intercalation, a Fe2O3-MPG intercalation compound (Fe2O3-MPGIC) anode material was constructed by introducing iron precursors between the framework layers and subsequently converting them into Fe2O3 through annealing. The Fe2O3-MPGIC anode exhibits a high reversible capacity of 1000.6 mAh g-1 at 200 mA g-1 after 100 cycles and a good cycling stability of 504.4 mAh g-1 at 2000 mA g-1 after 500 cycles. This work can provide a reference for the feasible recycling of SG and development of high-performance anode materials for LIBs.

Photocatalytic degradation of ternary dye mixture using RGO, γ-Fe2O3 and ZnO based binary and ternary nanocomposites

In this work, we report on the improved photocatalytic degradation of a ternary dye mixture of Malachite green (MG), Methyl orange (MO), and Rhodamine B (RhB), by RGO-based binary (RGO/γ-Fe2O3) and ternary (RGO/γ-Fe2O3/ZnO) nanocomposites (NCs). These NCs are synthesized with a green, facile, and rapid microwave irradiation route using Mangifera Indica leaf extract as a reducing agent. X-ray diffraction (XRD) and scanning electron microscopy (SEM) give clear insight into the phase purity and uniform growth of γ-Fe2O3 and γ-Fe2O3-ZnO nanoparticles over the RGO sheets which confirms the reduction of iron and zinc precursors, and graphene oxide via Mangifera to form NCs. The binary and ternary NCs show 100 % degradation of ternary dye mixture in 40 min and 21 min, respectively, under UV irradiation. UV–Visible spectra confirm a reduced energy band gap, 1.96 eV for ternary NCs, and 2 eV for binary NCs as compared to 2.3 eV for γ-Fe2O3. The reduction in band gap and synergism amid RGO and nanoparticles of γ-Fe2O3 and ZnO presents that suppressed charge carrier recombination, enhanced charge carrier lifetime, improved interfacial charge transfer and availability of more active sites in RGO/γ-Fe2O3/ZnO ternary NCs are responsible for highly efficient photocatalytic activities. Reaction kinetics analysis reveals the suitability of the pseudo first-order kinetics and Freundlich model for dye degradation.

Influence of inevitable iron precursor anions on MIL-100(Fe) structure and its La(Ⅲ) adsorption performance

The influence of iron precursor anions on the structure and properties of MIL-100(Fe) has often been overlooked. In this study, iron chloride hexahydrate and iron nitrate nonahydrate were used to synthesize MIL-100(Fe)-Cl and MIL-100(Fe)-N, respectively. Characterization comparisons revealed that MIL-100(Fe)-Cl exhibited a higher organic ligand content and a larger specific surface area. Subsequently, the adsorption properties of both materials for the rare-earth element lanthanum (La(Ⅲ)) were investigated. MIL-100(Fe)-Cl demonstrated superior La(Ⅲ) adsorption performance, with a maximum adsorption capacity of 54.7 mg·g−1, which is more than twice that of MIL-100(Fe)-N at 25.5 mg·g−1. The adsorption rate of MIL-100(Fe)-Cl for low-concentration La(Ⅲ) approached 100 % and sustained effective adsorption under weakly acidic conditions. The La(Ⅲ) adsorption processes on MIL-100(Fe)-Cl and MIL-100(Fe)-N were spontaneous and endothermic, involving both physisorption and chemisorption. Notably, a strong chemical interaction occurred during La(Ⅲ) adsorption by MIL-100(Fe)-Cl, whereas ion exchange was predominant in MIL-100(Fe)-N. Through further exploration of the adsorption mechanism via FT-IR and XPS characterizations, the main chemical active sites were the uncoordinated –COOH and terminal –OH groups of the Fe trimer. This study underscores the significant impact of different iron precursors on the synthesis of MIL-100(Fe), highlighting the need for careful selection of these materials in precursor choice.

Square-planar iron imido complexes containing strong-field pincer ligands as models for active species in catalytic nitrene transfer

Treatment of the iron(I) precursor, [Fe(N2)(tBuPNP)] (tBuPNP = anion of 2,5-bis(di-tert-butylphosphinomethyl)pyrrole), with mesitylazide (mesityl = 2,4,6-trimethylphenyl) results in the formation of a new four-coordinate iron imido complex, [Fe(NMes)(tBuPNP)], which serves as a model for reactive metal-nitrene intermediates in catalytic C–H amination. The solid-state structure of the complex exhibits a rare square-planar geometry about the iron center with a nearly linear imido unit. In analogy to similar compounds of cobalt, the electronic structure of [Fe(NMes)(tBuPNP)] is assigned as low-spin Fe(II) ferromagnetically coupled to a nitrene radical giving an overall S = 3/2 groundstate. A similar imido species was detected spectroscopically by treatment of [Fe(N2)(tBuPNP)] with 1-adamantylazide, however, use of the less bulky nitrene source phenylazide results in formation of the tetrazido species, [Fe(κ2-N4Ph2)(tBuPNP)]. Unexpectedly, [Fe(NMes)(tBuPNP)] proved recalcitrant toward nitrene transfer reactions involving weak C–H bonds, but did react readily with CO to generate [Fe(CO)2(tBuPNP)]. The reactivity of the new imido species in the context of its unique geometry and electronic structure is discussed.

Degradation of reactive blue dye under UV irradation using iron based nanocomposites

Abstract The textile industry contributes significantly to environmental pollution through the discharge of non-biodegradable colored dye effluents, emphasizing the need for effective wastewater treatment methods. Traditional approaches, including physical and biological treatments, face limitations, necessitating exploration into advanced oxidation processes (AOPs). Iron-based photocatalysts, particularly those synthesized through green methods, have shown promise in degrading organic pollutants. In this study, iron nanocomposites, including CSINCs, ASINCs, and ACINCs, are synthesized by mixing two different plant extract mixtures with an Iron precursor solution. XRD analysis confirms cubic structures for the prepared nanocomposites, with crystalline sizes of 14.21, 15.79, and 28.74 nm, respectively. UV–vis spectrophotometer shows characteristic absorption peaks in the 380–400 nm range. FESEM imaging reveals spherical particles, and EDX analysis detects typical signals of Fe, O, and C. FTIR spectra indicate various functional groups present in the nanocomposites. The study further focuses on optimizing the degradation of Reactive Blue 171 (RB 171) dye, considering factors such as pH, concentration of RB 171, and photocatalyst concentration. The results demonstrate that ACINCs, specifically at a concentration of 10 mg/100 mL in a mixture with Reactive Blue dye at a concentration of 50 ppm, exhibit enhanced degradation under UV irradiation. This detailed investigation contributes to the understanding of the structural and functional characteristics of Iron nanocomposites and their potential application in the efficient degradation of textile dyes, emphasizing the importance of optimizing key parameters for enhanced photocatalytic performance.

Deposition of Fe-doped CdS films by spray pyrolysis from various precursors

Iron-doped cadmium sulfide films (Fe–CdS) were produced by spray pyrolysis using iron nitrate, chloride and sulfate as iron precursors. Based on experimental analysis data and thermodynamic calculations, it was found that the composition, uniformity and surface morphology of the films significantly depend on the nature of the iron precursor. It has been found that all synthesized Fe–CdS films can be used as master alloys for the manufacture of Fe:ZnSe laser elements.

Green Synthesis of Iron Nanoparticles Using an Aqueous Extract of Strawberry (Fragaria × ananassa Duchesne) Leaf Waste.

In this study, we analysed the potential use of dried strawberry leaves and calyces for the production of nanoparticles using inorganic iron compounds. We used the following iron precursors FeCl3 × 6H2O, FeCl2 × 4H2O, Fe(NO3)3 × 9H2O, Fe2(SO4)3 × H2O, FeSO4 × 7H2O, FeCl3 anhydrous. It was discovered that the content of polyphenols and flavonoids in dried strawberries and their antioxidant activity in DPPH and FRAP were 346.81 µM TE/1 g and 331.71 µM TE/1 g, respectively, and were similar to these of green tea extracts. Microimages made using TEM techniques allowed for the isolation of a few nanoparticles with dimensions ranging from tens of nanometres to several micrometres. The value of the electrokinetic potential in all samples was negative and ranged from -21,300 mV to -11,183 mV. XRF analyses confirmed the presence of iron ranging from 0.13% to 0.92% in the samples with a concentration of 0.01 mol/dm3. FT-IR spectra analyses showed bands characteristic of nanoparticles. In calorimetric measurements, no increase in temperature was observed in any of the tests during exposure to the electromagnetic field. In summary, using the extract from dried strawberry leaves and calyxes as a reagent, we can obtain iron nanoparticles with sizes dependent on the concentration of the precursor.

Polypyrrole Coating via Lemieux-von Rudloff Oxidation on Magnetite Nanoparticles for Highly Efficient Removal of Chromium(VI) from Wastewater.

An alternative way for the coating of polypyrrole (PPy) polymer on hydrophobic magnetite (Fe3O4) nanoparticles is reported here to capture toxic chromium ions, Cr (VI), present in water. Iron oxide magnetic nanoparticles (Fe3O4) were synthesized by the conventional coprecipitation technique using FeCl3·6H2O and FeSO4·7H2O iron precursors and subsequently modified with oleic acid (OA). Then OA-Fe3O4 hydrophobic nanoparticles were oxidized using the Lemieux-von Rudloff reaction to transfer OA into hydrophilic azelaic acid (AA) (HOOC(CH2)7COOH-modified magnetic nanoparticles (AA-Fe3O4). Finally, a PPy polymer coating was formed by a seeded polymerization of pyrrole, using AA-Fe3O4 as seeds. The average size of PPy/Fe3O4 nanocomposites is 12.33 nm and is almost spherical in shape. The surface composition is confirmed by FTIR and thermogravimetry analyses. An X-ray diffraction study confirmed the formation of highly crystalline Fe3O4 nanoparticles, and the crystallinity was retained after the surface modification. The adsorption study suggested that the Cr(VI) ion adsorption is highly pH-dependent and the maximum amount of adsorption is obtained at pH 2.0. The adsorption results revealed that the Langmuir model provided the best fit for the isotherm, with a maximum adsorption capacity reaching approximately 173.22 mg g-1 at 323 K. Spontaneous and endothermic adsorption processes were confirmed by evaluating the thermodynamic parameters obtained in this investigation. The kinetics study showed that the interaction between Cr(VI) ions and magnetic nanocomposites was directed by a pseudo-second-order rate process indicating chemisorption. The prepared PPy/Fe3O4 nanocomposites would be promising adsorbents to purify water by eliminating Cr(VI) metal ions from wastewater.

Catalytic aquathermolysis of contaminated polyolefin plastic waste over an in situ iron hydroxide/oxide nanocatalyst derived from an oil-soluble iron precursor

With the substantial increase in global plastic consumption over the past 50 y, society faces the challenges of managing and recovering resources from considerable amounts of plastic waste. A promising strategy for use in addressing this problem is to upcycle plastic waste into valuable materials via thermochemical conversion, and hydrothermal liquefaction, which uses low-cost and green H2O, has attracted attention as a sustainable technology. In this study, we introduced an aquathermolysis system using oil-soluble Fe-2-ethylhexanoate (Fe-2EH) as a catalyst precursor under superheated steam conditions to convert highly contaminated polyolefin plastic waste to liquid fuel. The excellent dispersibility and decomposition behavior of Fe-2EH facilitated the formation of highly dispersed in situ Fe-based catalysts, enabling their involvement in the early stages of aquathermolysis. The presence of H2O and the in situ catalyst significantly promoted the decomposition of C–X bonds (X = Cl, S, N, or O) rather than C–C bonds, and C–C cleavage was driven by thermal energy. Moreover, the presence of H2O with the catalysts reduced the proportion of non-paraffinic products, including olefins and aromatics that cause char/coke formation. During the reaction, the in situ catalyst particles comprised nanosized Fe oxide cores with Fe hydroxide-rich surfaces, preventing the accumulation of metal contaminants. Based on deuterium tracing studies, the H transfer index of the catalyst was closely related to the catalytic performance. These results indicated that catalytic aquathermolysis using Fe-2EH is an efficient system for use in improving product quality by effectively removing contaminants and suppressing char/coke formation.