Fe3O4 Loading Research Articles

Silk fibroin nanoparticles for locoregional cancer therapy: Preliminary biodistribution in a murine model and microfluidic GMP-like production.

Silk fibroin nanoparticles (SFNs) have been widely investigated for drug delivery, but their clinical application still faces technical (large-scale and GMP-compliant manufacturing), economic (cost-effectiveness in comparison to other polymer-based nanoparticles), and biological (biodistribution assessments) challenges. To address biodistribution challenge, we provide a straightforward desolvation method (in acetone) to produce homogeneous SFNs incorporating increasing amounts of Fe2O3 (SFNs-Fe), detectable by Magnetic Resonance Imaging (MRI), and loaded with curcumin as a model lipophilic drug. SFNs-Fe were characterized by a homogeneous distribution of the combined materials and showed an actual Fe2O3 loading close to the theoretical one. The amount of Fe2O3 incorporated affected the physical-chemical properties of SFNs-Fe, such as polymer matrix compactness, mean diameter and drug release mechanism. All formulations were cytocompatible; curcumin encapsulation mitigated its cytotoxicity, and iron oxide incorporation did not impact cell metabolic activity but affected cellular uptake in vitro. SFNs-Fe proved optimal for biodistribution studies, as MRI showed significant nanoparticle retention at the administration site, supporting their potential for locoregional cancer therapy. Finally, technical and economic challenges in SFN production were overcome using a GMP-compliant microfluidic scalable technology, which optimized preparation to produce smaller particle sizes compared to manual methods and reduced acetone usage, thus offering environmental and economic benefits. Moreover, enabling large-scale production of GMP-like SFNs, this represents a considerable step forward for their application in the clinic.

4D Printing of Multifunctional and Biodegradable PLA-PBAT-Fe3O4 Nanocomposites with Supreme Mechanical and Shape Memory Properties.

4D printing magneto-responsive shape memory polymers (SMPs) using biodegradable nanocomposites can overcome their low toughness and thermal resistance, and produce smart materials that can be controlled remotely without contact. This study presented the development of 3D/4D printable nanocomposites based on poly (lactic acid) (PLA)-poly (butylene adipate-co-terephthalate) (PBAT) blends and magnetite (Fe3O4) nanoparticles. The nanocomposites are prepared by melt mixing PLA-PBAT blends with different Fe3O4 contents (10, 15, and 20 wt%) and extruded into granules for material extrusion 3D printing. The morphology, dynamic mechanical thermal analysis (DMTA), mechanical properties, and shape memory behavior of the nanocomposites are investigated. The results indicated that the Fe3O4 nanoparticles are preferentially distributed in the PBAT phases, enhancing the storage modulus, thermal stability, strength, elongation, toughness, shape fixity, and recovery of the nanocomposites. The optimal Fe3O4 loading is found to be 10 wt%, as higher loadings led to nanoparticle agglomeration and reduced performance. The nanocomposites also exhibited fast shape memory response under thermal and magnetic activation due to the presence of Fe3O4 nanoparticles. The 3D/4D printable nanocomposites demonstrated multifunctional multi-trigger shape-memory capabilities and potential applications in contactless and safe actuation.

Immobilization of Pb2+ and Cd2+ in water by sodium alginate magnet-biochar composite and LCA evaluation

Heavy metal pollution in water is one of the most pressing global environmental problems. In this research, two kinds of phosphorus-modified walnut shell biochar gel beads (P@WSBGB) and ferromagnetic gel beads (P@FWSBGB) were prepared by an environmentally friendly method to solve this problem. The maximum adsorption capacities for Pb2+ were 197 mg g−1 for P@WSBGB and 180 mg g−1 for P@FWSBGB, and for Cd2+, they were 125 mg g−1 and 108 mg g−1, respectively. Although Fe3O4 loading reduced adsorption capacity by approximately 10 %, life cycle assessment(LCA) showed that P@FWSBGB had a lower environmental impact than P@WSBGB when adsorbing the same amount of 1 mg of Pb2+. This indicates that a reasonable load of Fe3O4 can reduce the environmental impact. Conversely, when adsorbing Cd2+, the result was the opposite, demonstrating that unreasonable loading increased the environmental impact. To ensure that Fe3O4 loading did not lead to increased environmental impacts, we further analyzed the data to determine the optimal Fe3O4 loading level. The optimal Fe3O4 loading was determined to be 12.5 % for Pb2+ adsorption and <12.5 % for Cd2+. The main adsorption mechanism is that the -COOH and -OH groups on the surface of biochar form complexes with Pb2+ and Cd2+. Ion exchange, electrostatic attraction, co-precipitation of phosphate, and physical adsorption also contribute to the removal of Pb2+ and Cd2+. In summary, this research solved the challenge of difficult recycling of biochar powder and provides new insights for the synthesis and condition optimization of magnetic adsorbents.

Magnetically separable sorbent based on activated carbon derived from a new precursor Rhizoclonium hookeri for facile oil spill clean-up

A huge quantity of synthetic toxic materials ends-up in water bodies causing long-lasting environmental and economic impacts due to catastrophic oil spill. Exploring marine algae as sorbent materials for oil spill remediation is a relatively new area and holds great potential. Herein, macroalgae Rhizoclonium hookeri (RH) derived magnetically recoverable RH-activated carbon (RHAC@Fe3O4) composite has been proposed as an innovative and robust strategy for oil spill clean-up. The application of RHAC@Fe3O4 composite was investigated for oil removal by varying time (10–60 min), dosage (0.2–1 g) and temperature (20, 30, 40 °C) to ascertain its optimal performance using both unused and used motor oil. Characterization studies showed that KOH activation resulted in developing pore structure and surface functionalities in the algal biochar. The percentage of oil uptake from simulated oil spill was over 90 % in 30 min at room temperature using 0.8 g composite. Moreover, Fe3O4 loading onto carbon material allowed magnetic separation as a convenient alternative to filtration for the recovery of oil laden composite. Apart from superior oil removal ability, synthesized composite demonstrated robust performance up to four cycles in synthetic sea water matrices. Comparative study revealed better oil sequestration efficiency of RHAC@Fe3O4 (93 %) as compared to its precursors, i.e. algal biochar (71 %) and AC (88 %). Based on these findings, it is advocated that designed RHAC@Fe3O4 composite being eco-friendly, economical and readily recoverable with enhanced oil uptake ability could potentially be an innovative platform for oil spill clean-up applications.

Efficient Defluoridation of Drinking Water using Mesoporous Magnetic Malachite Nanocomposites

The study evaluated the efficacy of magnetic mesoporous Malachite nanoparticles (NPs) in eliminating fluoride (F−) from drinking water. Screening experiments were conducted to gauge the F− adsorption capabilities of the synthesized material under different Fe3O4 loading conditions. Among the various nanomaterials examined, 0.25-Fe-M demonstrated optimal performance, exhibiting consistent Fe3O4 distribution with a crystal size of 16.66 nm with revealed irregular morphology exhibiting magnetic properties, a surface area of 13.595 m2/g and a pore size of 1.6574 nm. The optimized reaction conditions determined were: 10 minutes of contact time, a NC dose of 0.5 mg/mL, and an F− concentration of 10 mg/L. The maximum adsorption capacities recorded were 6.57 mg/g for Fe3O4 NPs and 7.87 mg/g for malachite NPs. Notably, the optimal adsorption capacity for F− removal was achieved with 0.25 Fe-M-NCs, reaching 8.44 mg/g, demonstrating superior performance compared to other NCs. The interplay between surface area, pore volume, and adsorption is intricate and contingent upon the unique properties of the adsorbent and adsorbate, with specific interactions governing the adsorption process. Furthermore, this study unveiled accelerated adsorption with shorter contact time and high adsorption capacity at the working pH.

Magnetic graphene oxide incorporated with Fe2O3 for the removal of lead (II) ions

The objective of this research work is to synthesise graphene oxide (GO) with iron oxide (Fe2O3) nanoparticles as a magnetic adsorbent for lead ion (Pb2+) removal. In this work, the effect of synthesis parameters of GO/Fe2O3 (Fe2O3 loading weight ratio, synthesis time and calcination temperature) and adsorption parameters (initial Pb2+ concentration, adsorption temperature and contact time) on Pb2+ removal were investigated. The adsorption experiment was carried out in a batch system, and the synthesised GO/Fe2O3 adsorbent was characterised using TGA and N2 sorption-desorption analyses. The adsorption characteristics of Pb2+ using GO/Fe2O3 adsorbent were analysed using adsorption isotherms and kinetic study. The optimal synthesis parameters were found to be a 1:0.5 ratio for GO/Fe2O3, a synthesis time of 60 min and a calcination temperature of 400°C, resulting in a Pb2+ removal rate of 96% and adsorption capacity of 49.85 mg Pb2+/g adsorbent. The GO/Fe2O3 adsorbent synthesised at 400°C and a 1:0.5 ratio exhibits a larger surface area and smaller pore diameter, 98.20 m2/g and 15.67 nm, respectively, compared to other samples. Increasing the synthesis temperature decreases the growth and formation of GO/Fe2O3, reducing the surface area. Experimental results revealed that the adsorption of Pb2+ using GO/Fe2O3 adsorbent fitted the pseudo-second-order kinetic and was best described by the Langmuir isotherm with a high correlation coefficient (R2 &gt;0.99).

Adsorptive removal of cationic dyes from wastewater using a novel sodium alginate-based iron oxide nanocomposite hydrogel: DFT and advanced statistical physics modelling

A novel Sodium alginate-based hydrogel reinforced with varying Fe2O3 nanoparticles loading (NCH) was synthesized to remove cationic dyes methylene blue (MB) and crystal violet (CV). The NCH, with 5 % Fe2O3 loading, demonstrated optimal removal efficiency for both dyes. Detailed spectroscopic, microscopic, and spectrometric characterization techniques verified the nanocomposite structure and dye adsorption. Batch experiments revealed that at pH: 9, with a 20 mg 100 mL−1 adsorbent dose and times of 60 min for MB and 40 min for CV, with an initial concentration of 500 mg L−1, maximum adsorption capacities were achieved. MB and CV adsorption onto NCH showed distinct mechanisms: MB via physical interaction, CV via both physical and chemical interactions, including electrostatic forces and hydrogen bonding. Despite differences, the Langmuir-Freundlich model best fit the equilibrium isotherms, suggesting monolayer adsorption dominated, even with heterogeneous surface sites on NCH. A dual-site M2 statistical physics model revealed that MB and CV adsorption occurred via a multi-molecular vertical configuration on the binding sites, with heterogeneous adsorption sites contributing to dye uptake. Density functional theory demonstrated higher adsorption affinity for MB over CV, primarily due to hydrogen bonding and electrostatic interactions. NCH exhibited 80 % dye removal efficiency after five cycles, highlighting its potential for industrial effluent treatment.

Recycling the polyethylene into fuels via an olefin-intermediate tandem catalysis over Fe2O3/USY catalysts

Catalytic pyrolysis of waste plastics using iron-based metal-acid catalysts is a promising waste-to-energy technology to deliver clean renewable fuels. While these catalysts show valid catalytic activity during pyrolysis, their ability to guide tandem reactions over metal and acid sites remains uncertain. In this study, we employ the Fe2O3/USY catalysts to recycle polyethylene (PE) into liquid fuels, and demonstrate the tandem catalysis of the Fe2O3/USY catalysts during PE depolymerization. The highest fuel oil yield obtained was 78.1 % after Fe2O3/USY catalysis (5 % Fe loading, Si/Al ratio = 80). The resulting oil predominantly falls within the gasoline range, with a carbon number distribution rich in C5–C9 range. The oil composition comprises 71.3 % olefins and 16.7 % paraffins, mostly isomeric, while few aromatics were obtained. Comparative experiments confirm that PE depolymerization over the metal and acid sites of Fe2O3/USY catalysts involves an olefin-intermediate tandem pathway: the Fe2O3 enhances olefin-intermediate generation through its dehydrogenation activity, while the USY allows these olefin-intermediates to undergo further cleavage over the acid sites. Although the Fe2O3 loading on USY enhances PE cracking by facilitating olefin-intermediate generation in tandem catalysis, the reduced acidity inhibits PE cracking. Therefore, when aiming for oil production via PE pyrolysis, the delicate balance between reduced acidity and increased dehydrogenation activity after Fe2O3 loading must be taken into account.

Preparation and Visible Light Catalytic Performance of Fe3O4/Ag/BiVO4/Sepiolite Composites

AbstractTo increase specific surface area and light utilization of photo‐catalysts, a series of Fe3O4/Ag/BiVO4/sepiolite composites with different Fe3O4 contents were synthesized via co‐precipitation. The structure, composition, and optical properties of these composites were characterized using X‐ray diffraction (XRD), nitrogen adsorption and desorption (BET), UV‐Vis diffuse reflectance spectroscopy (UV‐Vis DRS), and fluorescence spectroscopy (PL). The photo‐catalytic activity of the composites was further evaluated using rhodamine B as a model for photo‐catalytic degradation. The results revealed that the composites with optimal Fe3O4 loading exhibited the narrowest bandgap width, approximately 2.13 eV, and the highest electron‐hole pair separation efficiency. Rhodamine B could be almost completely degraded within a short illumination time in the presence of the Fe3O4/Ag/BiVO4/sepiolite composites. The degradation mechanism of rhodamine B was proposed to involve the improvement of the photo‐catalytic activity of the resulting composites by the Fe3O4 and the Z‐type heterojunction structure. Additionally, the composites could be recycled and reused multiple times, making them an environmentally friendly and sustainable option.

Sodium titanate nanostructured modified by green synthesis of iron oxide for highly efficient photodegradation of dye contaminants

Abstract In this study, sodium titanate (ST)/iron oxide (Fe2O3) was successfully prepared as a novel binary photocatalyst for the first time to enhance the photocatalytic activity. The prepared photocatalyst was used in the photodegradation of methylene blue (MB) dye under sunlight and a tungsten lamp. The green synthesis method using orange peel extract was employed to prepare Fe2O3, while the hydrothermal method was used to synthesize ST. To achieve optimal photocatalytic efficiency, the loading of Fe2O3 onto ST was carefully controlled. The average crystallite size of ST, Fe2O3, and ST@Fe2O3 (with a 1:1 wt% ratio) was 999.8, 81.9, and 104 nm, respectively, using the Williamson–Hall (W–H) model. Optical analysis revealed that ST@Fe2O3 had a smaller direct bandgap (2.54 eV) compared to ST@0.3 Fe2O3 (2.70 eV) and ST@0.5 Fe2O3 (3.24 eV). The photodegradation of MB was analyzed considering the weight of the photocatalyst, the irradiation time, and the dye concentration. In-depth explanations of stability and kinetic models were also provided. Remarkably, the ST@Fe2O3 photocatalyst demonstrated superior performance compared to the other evaluated photocatalysts, completely degrading MB dye within just 60 min of solar light exposure. Incorporating Fe2O3 into ST effectively reduces the recombination of photo-produced electron/hole (e/h) pairs and broadens the response range of the solar spectrum. Based on these findings, ST@Fe2O3 appears to have a promising future as a practical photocatalyst for degrading various dye pollutants in wastewater.

Multi-heterointerface integration in nitrogen-doped Ti3C2Tx@Fe3O4 nanocomposites for superior microwave absorption

Engineering a lightweight and thin microwave absorber through the design of multiple heterogeneous interfaces represents a significant challenge. Here, we synthesized a nitrogen (N)-doped Ti3C2Tx@Fe3O4 (N–Ti3C2Tx@Fe3O4) nanocomposite with a sandwich-like structure through a solvothermal approach using hydrazine hydrate as the N donor. The numerous Ti3C2Tx electron transfer pathways of Ti3C2Tx enable the realization of a hierarchical conduction network within N–Ti3C2Tx@Fe3O4. The introduction of defects through N doping and the integration of Fe3O4 with Ti3C2Tx are pivotal for enhancing the dipole polarization. The heterogeneous interfaces in N–Ti3C2Tx@Fe3O4, coupled with Fe3O4 components, substantially boost the electromagnetic wave (EMW) absorption performance of the composite. An optimal N integration and the loading of Fe3O4 in Ti3C2Tx result in an improved impedance matching of N–Ti3C2Tx@Fe3O4. The synergistic effect of the improved impedance matching and the strong EMW attenuation capability endow N–Ti3C2Tx@Fe3O4 with enhanced microwave absorption (MA) properties. Specifically, at a thickness of 1.04 mm, the composite exhibits the effective absorption bandwidth (3.92 GHz; 14.08–18.00 GHz), surpassing that of Ti3C2Tx. At a thickness of 0.98 mm, it exhibits a maximum reflection loss of −40.28 dB at 17.25 GHz, which substantially exceeds that of Ti3C2Tx. Furthermore, it shows a maximum Radar Cross Section reduction of 21.32 dB cm2. A cotton fabric was coated with N–Ti3C2Tx@Fe3O4, and it was found to exhibit enhanced heat conduction and dissipation, at rates 3.83 and 4.64 times greater than those of uncoated cotton, respectively. These results highlight the considerable potential of N–Ti3C2Tx@Fe3O4 nanocomposites for use in far-field applications. It is envisaged that the exceptional MA and thermal management properties of N–Ti3C2Tx@Fe3O4 nanocomposites will provide a novel avenue for crafting lightweight and thin EMW absorbing materials.

Generation and persistency of combustion-derived environmentally persistent free radicals from phenolic compounds over a Fe2O3/SiO2 surface

Combustion of organic solid wastes releases phenolic compounds which can act as precursors in the formation of environmentally persistent free radicals (EPFRs) in the post-flame, cooling zone of waste combustion. The study investigated the generation mechanism of EPFRs from phenolic compounds catalyzed by transition metals in air atmosphere under simulated combustion conditions. Representative combustion-derived phenolic compounds were used, and SiO2 particulates containing different mass ratio of Fe2O3 were synthesized as carriers. EPFRs formed had g-factors between 1.9998 and 2.0066, indicating phenoxyl-, cyclopentadienyl-, and semiquinone-type radicals, along with paramagnetic F-centers. The promotion effect of phenolic compounds on EPFR formation during heating decreased as catechol > hydroquinone > phenol > p-cresol. This trend is related to hydroxyl groups and activation energy. In particular, catechol chemically adsorbed on Fe2O3 at 600 K led to the formation of EPFRs with relatively high spin concentrations (up to 1.28 × 1017 spin/g). Higher Fe2O3 concentrations promoted the transformation of phenoxyl-type radicals into cyclopentadienyl-type and paramagnetic F-centers. However, as the Fe2O3 loading increased from 1.25% to 5%, the density of EPFRs decreased. The findings related to the influence of various precursors and Fe2O3 concentration on EPFR formation provide valuable insights for estimating EPFR generation and associated risk during combustion processes.

Promotional effects of Fe2O3 additive on the NH3-SCR activity and alkali resistance of MoTiOx catalysts

Catalyst is the core of selective catalytic reduction (SCR) technology, and an ideal SCR technology requires that the catalyst should have high activity and resistance to alkali metal poisoning. Therefore, in this paper, the influence of Na poisoning on the catalytic performance of Fe2O3-MoTiOx catalysts in the selective catalytic reduction (SCR) reaction was investigated, and the anti-alkali mechanism was revealed. The Fe2O3-MoTiOx catalyst demonstrated the NO conversion was 90 % at a broad temperature range of 225-400 °C when the Fe2O3 loading ratio was 20 wt%. Besides, 80 % NO conversion rate of the Fe2O3-MoTiOx catalyst at 320 °C was still achieved even at a Na+ concentration of 300 μmol g-1. The phenomenon was attributed to the interaction between Fe and Ti species, which could generate more Lewis acid centers and facilitate the adsorption activation of NH3. During the Na poisoning process, Na ions predominantly adsorbed on the Fe2O3, effectively safeguarding the MoTiOx catalyst. Additionally, although the Brønsted acid sites were deteriorated because of Na poisoning, the abundant Lewis acid sites were preserved for NHx adsorption. Therefore, the Na-poisoned Fe2O3-MoTiOx catalyst maintained efficient NH3 adsorption and NO activation. The work provided theoretical guidance and data support for the development of novel alkali-resistant SCR catalysts.

High Temperature and FORC Investigations of Semiconducting/Ferromagnetic Nanocomposites

In the frame of this work the temperature-dependency of the magnetization of various composite systems consisting of porous silicon (PSi) and silicon nanotubes (SiNTs) with embedded Ni, NiCo, FePt, and Fe3O4 structures is discussed. The temperature is varied between 80 and 1273 K which allows to determine the Curie Temperature of the composites which is higher than for the corresponding bulk materials. Magnetic cross-talk between metal deposits can be controlled by the morphology of the porous silicon (pore diameter and distance between the pores) or silicon nanotubes (inner diameter and wall thickness) and also by the distribution and size of the deposits within the pores. To get a clear knowledge about the magnetic interactions single hysteresis curves are not sufficient and thus first order reversal curves (FORC) are performed. Magnetic coupling is present for Ni, Co and NiCo deposits, whereas in the case of Fe3O4 and FePt nanoparticle loading no magnetic cross-talk between the particles is observed.

Degradation of TCH by Fe3O4/B4C catalyzed heterogeneous Fenton oxidation

In this work, Fe3O4/B4C (FeB) composites were successfully prepared by a facile co-precipitation process. FeB composites were characterized using XRD, FTIR, N2 adsorption-desorption, XPS, etc techniques and then used as heterogeneous Fenton catalysts to activate green oxidant (H2O2) for the degradation of TCH. The removal efficiency of TCH by FeB composites was explored including different parameters of Fe3O4 loading on B4C, catalyst dosage, initial solution pH, H2O2 dosage, and reaction temperature. The highest photo-Fenton catalytic efficiency was obtained for the composites with a mass ratio of Fe3O4 to B4C of 1:0.75. At this time, the removal efficiency of Fe3O4/B4C was 2 times and 391 times that of the parent Fe3O4 and B4C, respectively, and B4C can effectively improve the efficiency of the Fenton cycle. h+, e-, and ·OH were mainly responsible for the degradation of TCH by Fe1B0.75 composites. After repeated use for five times, the removal efficiency of the catalyst was reduced by only 8.0%. The disparity in work functions by density functional theory calculations confirmed the formation of an internal electric field at the Fe3O4/B4C composites interface, which contributed the transfer of charge carriers between the Fe3O4 and B4C. Moreover, the FeB composite showed a high stability, indicating that FeB composites may be a promising heterogeneous catalyst.

Aquatic invasive plant biomass-derived magnetic porous biochar prepared by sequential carbonization and coprecipitation for diethyl phthalate removal from water

Low-cost multifunctional sorbents are urgently needed, especially for the treatment of emerging pollutants that are widely distributed in various water environments. This work transformed an aquatic invasive plant, Pistia stratotes, into magnetic porous biochars (P-MPBs) based on a proposed strategy involving sequential carbonization to increase porosity and subsequent coprecipitation with ferric salts. Both the porous structure (specific surface area of up to 996.86 m2/g) and high Fe3O4 loading (saturation magnetization of up to 23.48 emu/g) were maintained. A typical plasticizer, diethyl phthalate (DEP), was selected as a model emerging organic pollutant, and the sorption quantity of the P-MPBs reached 490.04 mg g−1, which is much higher than that of many reported sorbents, especially magnetic sorbents. P-MPBs can be reused multiple times due to their excellent separation characteristics and stable structure. On the basis of kinetics and isotherm analysis, multilayer sorption, including pore filling, hydrogen bonding, π–π stacking, and partitioning, was the main DEP sorption process for the P-MPBs. Our study suggested that the proposed method could be promising and inspiring for the transformation of biowaste into excellent magnetic porous biochar that is recyclable and highly efficient at removing pollutants in water.

Optimizing the fluoride removal from drinking water through adsorption with mesoporous magnetic calcite nanocomposites

Fluoride (F−) contamination in groundwater is a global concern arising from natural processes and human activities. This study investigates the adsorption of F− using surface-activated magnetic calcite nanocomposites (NCs) synthesized via co-precipitation assisted wet-impregnation (CP-WI). Various Fe3O4 loadings and calcination temperatures (300 °C and 500 °C) were explored to optimize synthesis parameters. Batch adsorption experiments were conducted to assess the performance of synthesized nanoparticles (NPs) and nanocomposites (NCs). BET, FTIR spectroscopy, X-ray diffraction, and SEM characterization techniques were employed to analyze the physicochemical properties, including surface functional groups, crystallite size, and morphology. The adsorption process was investigated using RSM statistical design with adsorbent dose (A) and F− concentration (B) as independent variables. 0.5Fe-C-NC-5, calcined at 500 °C, exhibited superior adsorption capacity (7.81 mg/g) compared to Fe3O4 and calcite NPs (6.57 mg/g and 6.81 mg/g, respectively). Maximum F− adsorption occurred within 10 min of contact time. NPs and NCs that were exposed to higher calcination temperatures, reaching up to 500 °C, showed an increase in crystallite development while experiencing a reduction in surface area and an enlargement of pore size compared to those treated at lower temperatures. The BET analysis revealed a narrow, slit-like mix of microporous and mesoporous surface with a type IV isotherm and H3 hysteresis loop, indicating multilayer adsorption followed by capillary condensation. The SEM images displayed columnar shapes of CaCO3 polymorph in the prepared Fe3O4-calcite NP and Fe–C NP, which can be attributed to lower calcination or synthesis temperatures.

Potentials of emergent plant residue derived biochar to be alternative carbon-based phosphorus fertilizer by Fe(II)/Fe(III) magnetic modification

Emergent plants have been remarkably effective in reducing phosphorus (P) discharge from ecological ditches; however, the treatment and recycling of these residues is a great challenge. In this study, magnetic biochars (MBs, i.e., MB-A, MB-C, and MB-T) were fabricated from three emergent plant residues (Acorus calamus L., Canna indica L., and Thalia dealbata Fraser, respectively) and modified with Fe(II)/Fe(III). Scanning electron microscopy-energy dispersive spectroscopy and X-ray diffraction spectra confirmed the successful loading of Fe3O4 and FeO(OH) onto the surfaces of the MBs. Batch adsorption experiments showed that MBs exhibited a higher P adsorption capacity than that of the raw biochars. Within the range of 0.8–43.0 mg L−1 in solution, the adsorption capacities of P by MB-A, MB-C, and MB-T were 304.6–5658.8, 314.9–6845.6, and 292.8–5590.0 mg kg−1, with adsorption efficiencies of 95.2–32.9%, 98.4–39.8%, and 91.5–32.5%, respectively. The primary mechanisms that caused P to adsorb onto the MBs were inner-sphere complexation and electrostatic attraction. Low pH conditions were more beneficial for the P adsorption of the MBs, while co-existing anions had a negative impact with the following order: HCO3− > SO42− > Cl−≈NO3−. The P-31 nuclear magnetic resonance results further demonstrated that the main adsorbed P species on the MBs was orthophosphate, followed by orthophosphate monoesters and DNA. Overall, MBs offer a resource utilization strategy for emergent plant residues and P-laden MBs are promising alternative P fertilizers.Graphical

Improved PMS activation by natural sepiolite/Fe3O4 composite for effective tetracycline degradation: Performance, mechanism and degradation pathway

In this study, Fe3O4/sepiolite composites as peroxymonosulfate (PMS) catalysts were successfully synthesized via a simple water bath method for tetracycline (TC) degradation. The results indicated that the composite with 70% Fe3O4 loading amount exhibited the highest TC degradation efficiency (90.12%), and its reaction rate constant (0.02193 min−1) was around 2.07 times higher than that of pure Fe3O4. The enhanced catalytic activity was mainly attributed to the uniform deposition of Fe3O4 nanoparticles with smaller grain size (17.24 nm) on sepiolite, leading to the larger specific surface area (120.61 m2/g) and more exposed reaction active sites. The electron paramagnetic resonance (EPR) and quenching experiments displayed that 1O2 species played the predominant roles in TC degradation process. Besides, potential catalytic mechanisms and degradation pathways of TC were proposed. The toxicity of TC was reduced during the degradation process. Overall, this work can provide a new strategy for the rational design of promising mineral-based PMS catalyst for the wastewater treatment.

A feasible recycling route for spent graphite: Microwave-assisted puffing with Fe2O3 loading to construct high-performance anode for lithium-ion batteries

Nowadays, one of the important issues associating with the lithium-ion battery industry is to address the inefficient utilization of spent graphite from plenty of spent batteries. Conventional methods including discarding or burning will exacerbate the environmental risks, which calls for novel routes to optimize the recycling of spent graphite. This study proposes a novel recycling strategy for spent graphite to construct Fe2O3@microwave-puffed graphite (Fe2O3@MPG) composite anode for high-capacity lithium storage. By means of mild intercalation followed by microwave treatment, spent graphite is converted to puffed graphite which can be used as framework for loading Fe2O3 to form Fe2O3@MPG with sandwich structure. This sandwich structure can provide conductive networks and channels to enhance conductivity and Li ions transfer, as well as confine Fe2O3 in microwave-puffed graphite framework to ease the structural instability caused by the volume change of Fe2O3, thereby endowing the Fe2O3@MPG composite with superior rate performance, high capacity, and excellent structural stability. The Fe2O3@MPG electrode possesses a specific capacity of 1100 mAh g−1 at 200 mA g−1, exhibits excellent rate performance with a capacity of 632 mAh g−1 at 2000 mA g−1, and delivers an outstanding cycling performance for 500 cycles. This study not only provides an important method for the efficient recycling of spent graphite but develops a universal method for modifying transition metal oxides anode utilizing spent graphite, thereby promoting the closed-loop lifecycle of graphite and the resource sustainability in the LIBs industry.