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Water pollution is one of the major concerns due to rapid industrialization and urbanization. Wastewater treatment has been an area of great interest for the researchers and among many technologies developed for water treatment, adsorption is the most preferred due to its efficiency and ability of been economical method. In this research, eggshell powder (ESP) is converted into modified eggshell powder (MESP) through chemical and thermal treatment (at 550 °C for 2 h) to use it as an adsorbent to remediate Pb2+ and Methylene blue (MB) from water, then it is transferred into modified eggshell powder magnetic composite (MESPMC) with iron coating to resolve the separation challenges and to boost the MESP's adsorption efficiency. FTIR analysis identified the functional groups of ESP, MESP, and MESPMC. XRD analysis reveals a hexagonal crystal structure of calcite in MESP and a combination of the hexagonal crystal structure of calcite and the cubic crystal structure of iron in MESPMC. The Scherrer equation is used to determine the average crystallite sizes of MESP and MESPMC, which are 22.59 nm and 12.15 nm, respectively. The SEM image shows the irregular shape of the MESP and MESPMC particles, as well as the active coating layer in MESPMC. EDX analysis reveals that Ca (20.92 %), O (56.83 %), and Fe (41.03 %), O (48.83 %) are the most abundant elements in MESP and MESPMC respectively. TGA analysis points out that MESPMC outperforms MESP in terms of thermal stability between 600 and 750 °C. MESP and MESPMC were found to be very efficient adsorbent for lead and methylene blue in aqueous medium. At 40 mg/mL adsorbent dosage, ESP, MESP, and MESPMC had the highest yields of Pb2+ removal, with 46.996 %, 99.27 %, and 99.78 % respectively at 200 rpm for 60 min with 25 °C. Furthermore, at the 0.5 mg/mL adsorbent dosage, ESP, MESP, and MESPMC have the maximum removal efficiency of methylene blue, with 47.19 %, 90.1 %, and 92 %, respectively at 200 rpm for 30 min with 25 °C. In both cases, the removal efficiency of MESPMC is slightly higher than that of MESP and much higher than that of ESP. Additionally, the results confirm that MESP and MESPMC are potential environment-friendly bio sources to remediate heavy metal (Pb2+) and methylene blue dye from water.

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This review explores the expanding role of electrochemical sensors across diverse domains such as environmental monitoring, medical diagnostics, and food quality assurance. In recent years, iron-based electrocatalysts have emerged as promising candidates for enhancing sensor performance. Notable for their non-toxicity, abundance, catalytic activity, and cost-effectiveness, these materials offer significant advantages. However, further investigation is needed to fully understand how iron-based materials' physical, chemical, and electrical properties influence their catalytic performance in sensor applications. It explores the overview of electrochemical sensor technology, examines the impact of iron-based materials and their characteristics on catalytic activity, and investigates various iron-based materials, their advantages, functionalization, and modification techniques. Additionally, the review investigates the application of iron-based electrode material composites in electrochemical sensors for real sample detections. Ultimately, continued research and development in this area promise to unlock new avenues for using iron-based electrode materials in sensor applications.

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In this study, we developed new adsorbents derived from orange peel biochar (BCOP) and enhanced them with CoFe2O4 magnetic nanoparticles (BCOP/CoFe2O4) and MIL-53(Al) (BCOP/CoFe2O4/MIL-53(Al)). These adsorbents were utilized to remove fluoride (FL) ions from aqueous solutions. We analyzed the properties of these adsorbents using a range of techniques, including FTIR, XRD, SEM, EDX-Map, VSM, Raman spectroscopy, and BET. Our findings indicate that the components interact effectively with one another. Specifically, the BCOP/CoFe2O4/MIL-53(Al) sample exhibited a specific surface area of 196.430 m2/g and a magnetic saturation value of 9.704 emu/g. The maximum FL ion adsorption capacities for BCOP, BCOP/CoFe2O4, and BCOP/CoFe2O4/MIL-53(Al) were 7.618, 16.330, and 37.320 mg/g, respectively, indicating that the modifications significantly enhanced the adsorption capacity. The optimum fluoride ion removal rates using BCOP, BCOP/CoFe2O4, and BCOP/CoFe2O4/MIL-53(Al) were 97.88%, 98.23%, and 99.06%, respectively, at adsorbent doses of 2.5, 1.5, and 0.8 g/L, contact times of 90, 70, and 50 minutes, pH 4, temperature 50°C, and a FL concentration of 10 mg/L. Thermodynamic studies revealed that the adsorption process was spontaneous and endothermic, with increased randomness between the adsorbent and fluoride ions. Kinetic analyses showed that fluoride ion adsorption by BCOP/CoFe2O4/MIL-53(Al) followed a pseudo-second-order (PSO) model, while BCOP and BCOP/CoFe2O4 followed a pseudo-first-order (PFO) model. Additionally, the equilibrium data for fluoride ion adsorption on BCOP/CoFe2O4/MIL-53(Al) adhered to the Freundlich model, whereas the other samples conformed to the Langmuir model. The study evaluates the effectiveness of BCOP, BCOP/CoFe2O4, and BCOP/CoFe2O4/MIL-53(Al) in removing FL ions from glass manufacturing wastewater, highlighting the superior performance of the magnetic composite due to its enhanced surface area and functional groups. Notably, the adsorbents demonstrated good regenerative capabilities, maintaining high performance over multiple adsorption cycles.

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A comprehensive understanding of the enhancement mechanism of the substrate material is crucial to ensure the repeatability and functionality of SERS detection technology. Therefore, this study introduces a theoretical analysis method that integrates electromagnetic and chemical enhancement to achieve a comprehensive understanding of the SERS effect on the magnetic composite substrate. The visual model is employed in this study to comprehensively analyze and illustrate the electric field enhancement and optical effects of composite substrate materials. The study also elucidated the adsorption and charge transfer between the substrate material and target molecules. Based on this theory, Fe3O4@GO@Ag material was prepared and used to detect hydrophobic organic molecules such as polycyclic aromatic hydrocarbons (PAHs), with a concentration as low as 0.5 nM. This study comprehensively analyzed the SERS enhancement effect of the composite substrate for the first time, and prepared a magnetic composite substrate material for the detection of hydrophobic organic molecules, opening up a new avenue for theoretical guidance and experimental exploration in SERS detection and analysis.

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To prepare a soft magnetic powder core, the magnetic powder surface has to be insulated by phosphating treatment. Organic chemicals such as ethanol and acetone are generally used as solvents for phosphoric acid, which may cause serious environmental problems. This work proposed deionized water as the environmentally friendly phosphating solvent for FeSiCr powder. The soft magnetic composites (SMCs) were prepared using phosphoric acid for inorganic coating and modified silicon polymer for organic coating. The effect of different phosphating solvents, including deionized water, ethanol, and acetone, on the structure and magnetic properties of SMCs were investigated. It is found that the solvent affects the phosphating solution's stability and the phosphoric acid's ionization. The phosphoric acid is more stable in deionized water than in ethanol and acetone. The phosphating reaction in deionized water is also more stable in deionized water, resulting in a dense phosphate coating on the particle surface. The effects of phosphoric acid concentration and temperature on the magnetic properties of FeSiCr-based SMCs were further studied. With the increase in phosphoric acid concentration and temperature, the magnetic permeability and saturation magnetization of the powder core decrease, and the core loss decreases, followed by an increase. The optimized combination of properties was obtained for the SMCs phosphated with 0.2 wt.% phosphoric acid in deionized water at 35 °C, including a high effective permeability µe of 25.7, high quality factor Q of 80.2, low core loss Pcv of 709.5 mW/cm3 measured at 0.05 T @ 100 kHz, and high withstanding voltage of 276 V, due to the formation of uniform and dense insulating coating layers. In addition, the SMCs prepared with phosphated powder show good corrosion resistance. The anti-corrosion properties of the SMCs using deionized water as a phosphating solvent are better than those using ethanol and acetone.

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Chitosan (CS) polysaccharide is expected to exhibit greater ionic conductivity, which can be attributed to its increased amino group content when it is blended with different semiconducting materials. Herein, the work used this conducting ability of chitosan and prepared a heterogeneous MoS2-induced magnetic chitosan (MF@CS) composite via the co-precipitation method, which was used to scrutinize the catalytic performance with Methylene Blue (MB) and Malachite Green (MG) dyes by visible light irradiation. The saturation magnetization value of the MF@CS composite is found to be 7.8 emu/g, which is less when compared to that of pristine Fe3O4 (55.7 emu/g) particles. The bandgap of the MF@CS composite is âˆ¼ 2.17eV, which exceeds the bandgap (Eg) of bare MoS2 of 1.80 eV. The maximum color removal of 96.3 % and 93.4 % for MB and MG dyestuffs is recognized in the exposure of the visible spectrum, respectively. At a starting dye dosage of 30 mg/L, 0.1 g/L of MF@CS, a pH level of 8-11, and 70 min of contact with direct light. The photocatalyst provides extremely good durability for a maximum of five phases. Hence, the MF@CS matrix is a viable and appropriate substance for the efficient treatment of effluents containing dye molecules.

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Water contamination by harmful organic and inorganic compounds seriously burdens human health and aquatic life. A series of conventional water purification methods can be employed, yet they come with certain disadvantages, including resulting sludge or solid waste, incomplete treatment process, and high costs. To overcome these limitations, attention has been drawn to nanotechnology for fabricating better-performing adsorbents for contaminant removal. In particular, magnetic nanostructures hold promise for water decontamination applications, benefiting from easy removal from aqueous solutions. In this respect, numerous researchers worldwide have reported incorporating magnetic particles into many composite materials. Therefore, this review aims to present the newest advancements in the field of magnetic composites for water decontamination, describing the appealing properties of a series of base materials and including the results of the most recent studies. In more detail, carbon-, polymer-, hydrogel-, aerogel-, silica-, clay-, biochar-, metal-organic framework-, and covalent organic framework-based magnetic composites are overviewed, which have displayed promising adsorption capacity for industrial pollutants.

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Recently, there has been an escalating demand for advanced materials with superior magnetic properties, especially in the actuator domain. High coercivity (Hci), an essential magnetic property, is pivotal for programmable shape changes in magnetic actuators and profoundly affects their performance. In this study, a new Sm2Fe17-xCuxN3 magnet with a high Hci was achieved by modifying the temperature of the reduction-diffusion process─lowering it from 900 to 700 °C through the introduction of Cu and finer control over the structure and morphology of the Sm2Fe17-xCuxN3 magnetic component within the actuator composite. Consequently, the Sm2Fe17-xCuxN3 magnet demonstrated a remarkable Hci of 11.5 kOe, eclipsing the value of 6.9 kOe attained by unalloyed Sm2Fe17N3 at reduced temperatures. By capitalizing on the enhanced magnetic properties of the Sm2Fe17-xCuxN3 composite and incorporating poly(ethylene glycol) into the elastomer matrix, we successfully fabricated a robust actuator. This innovative approach harnesses the strengths of hard magnets as actuators, offering stability under high-temperature conditions, precision control, longevity, wireless functionality, and energy efficiency, highlighting the vast potential of hard magnets for a range of applications.

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Nowadays, NOR-containing wastewater has placed huge pressure on global ecology. In this study, a chemically-modified chitosan-based polymer was cross-linked with magnetite to prepare a novel magnetic composite adsorbent named Fe3O4/CS-P(AM-SSS) for norfloxacin (NOR) removal. The preparation conditions were optimized by single factor experiments and response surface methodology. A series of characterization analyses were carried out on the morphology, structure, and properties of Fe3O4/CS-P(AM-SSS), verifying that Fe3O4/CS-P(AM-SSS) was successfully prepared. Batch adsorption experiments showed that NOR was efficiently removed by Fe3O4/CS-P(AM-SSS), with a broad pH applicability of 3-10, short adsorption equilibrium time of 60 min, maximum adsorption capacity of 268.79 mg/g, and high regeneration rate of 86% after eight adsorption-desorption cycles. Due to the three-dimensional network structure and abundant functional groups provided by modified chitosan polymer, the superior adsorption capability of Fe3O4/CS-P(AM-SSS) was achieved through electrostatic interaction, π-π stacking, hydrophobic interaction, and hydrogen bonding. Adsorption process was exothermic and well fitted by the pseudo-second-order kinetic model and the Langmuir isothermal model. The presence of cations had a slight inhibitory effect on NOR adsorption, while humic acid nearly had no effect. In model swine wastewater, 90.3% NOR was removed by Fe3O4/CS-P(AM-SSS). Therefore, with these superior characteristics, Fe3O4/CS-P(AM-SSS) was expected to be an ideal material for treating NOR-containing wastewater in the future.

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The present study reports the synthesis, characterization, and application of sustainable magnetic biochar composite. The inedible fruits of Vateria indica, a powerful ayurvedic plant were hydrothermally transformed into magnetic biochar (BC-Fe3O4) in a single step and characterized by several sophisticated techniques. FESEM analysis portrayed fibrous irregular mesh-like biochar with surface clustered Fe3O4 nanoparticles, while the incidence of carbon, oxygen, and iron in the elemental analysis by EDS established magnetic biochar formation. Numerous peaks consistent with planes of (220), (311), (400), (422), (511), (440), and (120) also substantiated the occurrence of magnetite nanoparticles and biochar respectively, as analyzed by XRD. XPS analysis showed signals at 285.65 eV, 533.28 eV, 711.08 eV, and 724.68 eV corroborating a strong C-O bond, O1s orbit, Fe2+, and Fe3+ respectively. BC-Fe3O4 was superparamagnetic with saturation magnetization of 4.74 emu/g, as per VSM studies, while its specific surface area, pore volume, and pore diameter were 5.74 m2/g, 0.029 cm3/g, and 20.86 nm respectively. The Fenton-like degradation of methylene blue (5.0-25.0 ppm) was accomplished by synthesized BC-Fe3O4, in the presence of H2O2. Within 180 min, almost complete degradation was achieved, with first-order kinetics having rate constants between 0.0299 and 0.0167 min-1. Stability and recyclability studies performed over 7 cycles exhibited unaltered degradation between 93.98 and 97.59%. This study exhibits the exceptional characteristics and degradation capabilities of BC-Fe3O4 synthesized from a sustainable plant biomass.

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Our study is focused on optimizing the synthesis conditions for the in situ oxidation of Fe particles to produce Fe@Fe3O4 core-shell powder and preparation via co-precipitation of ZnFe2O4 nanoparticles to produce Fe@Fe3O4/ZnFe2O4 soft magnetic composites (SMC) through a hybrid cold-sintering/spark plasma-sintering technique. XRD and FTIR measurements confirmed the formation of a nanocrystalline oxide layer on the surface of Fe powder and the nanosized nature of ZnFe2O4 nanoparticles. SEM-EDX investigations revealed that the oxidic phase of our composite was distributed on the surface of the Fe particles, forming a quasi-continuous matrix. The DC magnetic characteristics of the composite compact revealed a saturation induction of 0.8 T, coercivity of 590 A/m, and maximum relative permeability of 156. AC magnetic characterization indicated that for frequencies higher than 1 kHz and induction of 0.1 T, interparticle eddy current losses dominated due to ineffective electrical insulation between neighboring particles in the composite compact. Nevertheless, the magnetic characteristics obtained in both DC and AC magnetization regimes were comparable to those reported for cold-sintered Fe-based SMCs.

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The increasing use of pharmaceuticals and the ongoing release of drug residues into the environment have resulted in significant threats to environmental sustainability and water safety. In this sense, developing a robust and easy-recovered magnetic nanocomposite with eminent photocatalytic activity is very imperative for detoxifying pharmaceutical compounds. Herein, a systematic study was conducted to investigate the photocatalytic ozonation for eliminating metronidazole (MET) from aqueous media utilizing the CuFe2O4/SiO2/ZnO heterojunction under simulated sunlight irradiation. The composite material was fabricated by a facile hydrothermal method and diagnosed by multiple advanced analytical techniques. Modelling and optimization of MET decontamination by adopting the central composite design (CCD) revealed that 90 % of MET decontamination can be achieved within 120 min of operating time at the optimized circumstance (photocatalyst dose: 1.17 g/L, MET dose: 33.20 mg/L, ozone concentration: 3.99 mg/min and pH: 8.99). In an attempt to scrutinize the practical application of the CuFe2O4/SiO2/ZnO/xenon/O3 system, roughly 56.18% TOC and 73% COD were removed under the optimized operational circumstances during 120 min of degradation time. According to the radical quenching experiments, hydroxyl radicals (HO•) were the major oxidative species responsible for the elimination of MET. The MET degradation rate maintained at 83% after seven consecutive runs, manifesting the efficiency of CuFe2O4/SiO2/ZnO material in the MET removal. Ultimately, the photocatalytic ozonation mechanism over the CuFe2O4/SiO2/ZnO heterojunction of the fabricated nanocomposites was rationally proposed for MET elimination. In extension, the results drawn in this work indicate that integrating photocatalyst and ozonation processes by the CuFe2O4/SiO2/ZnO material can be applied as an efficient and promising method to eliminate tenacious and non-biodegradable contaminants from aqueous environments.

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Recently, microwave absorption (MA) materials have attracted intensive research attention for their ability to counteract the effects of ever-growing electromagnetic pollution. However, conventional microwave absorbers suffer from complex fabrication processes, poor stability and different optimal thicknesses for minimum reflection loss (RLmin) and widest effective absorption bandwidth (EAB). To address these issues, we have used electrospinning followed by high-temperature annealing in argon to develop a flexible microwave absorber with strong wideband absorption. The MA properties of the carbon nanofibers (CNFs) can be tuned by adjusting annealing temperature, and are dependent on the composition and microstructure of the CNFs. The absorber membrane obtained at 800 °C consists of Fe0.64Ni0.36@graphite core-shell nanoparticles (NPs) embedded in CNFs, formed via a corrosion-like transformation from NiFe2O4 to Fe0.64Ni0.36 followed by surface graphitization. This nanostructure greatly enhances magnetic-dielectric synergistic loss to achieve superior MA properties, with an RLmin of -57.7 dB and an EAB of 6.48 GHz (11.20-17.68 GHz) both acquired at a thickness of 2.1 mm. This work provides useful insights into structure-property relationship of the CNFs, sheds light on the formation mechanism of Fe0.64Ni0.36@graphite NPs, and offers a simple synthesis route to fabricate light-weight and flexible microwave absorbers.

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Incorporating perception into robots or objects holds great potential to revolutionize daily human life. To achieve this, critical factors include the design of an integrable three-dimensional (3D) soft sensor with self-powering capability, a wide working range, and tuneable functionalities. Here, we introduce a highly compressible 3D-printed soft magnetoelastic sensor with a wide strain sensing range. Inspired by the lattice metamaterial, which offers a highly porous structure with tuneable mechanical properties, we realized a remarkably compliant 3D self-powering sensor. Using magnetoelastic composite materials and 3D printing combined with sacrificial molding, a broad design space for constituent materials and structures is investigated, allowing for tuneable mechanical properties and sensor performances. These sensors are successfully integrated with two robotic systems as the robot operation and perception units, enabling robot control and recognition of diverse physical interactions with a user. Overall, we believe that this work represents a cornerstone for compliant 3D self-powered soft sensors, giving impetus to the development of advanced human-machine interfaces.

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The aggravated problem of lead pollution, especially in aquatic environments, necessitates the development of eminent adsorbents that could radically solve this environmental problem. Hence, a new composite was constructed based on iota carrageenan (i.Carr), graphene oxide (GO) and magnetite (Fe3O4) for removing noxious Pb2+ ions. The GO@Fe3O4-i.Carr composite was characterized by VSM, SEM, XPS, XRD, FTIR and Zeta potential. The removal of Pb2+ ions attained a quick equilibrium of almost 30 min with a removal efficiency reaching 93.68 %. The removal of Pb2+ was boosted significantly, in the order of GO@Fe3O4-i.Carr(1:1) > GO@Fe3O4-i.Carr(1:3) > GO@Fe3O4-i.Carr(3:1). Moreover, acquired experimental data fitted the pseudo 2nd order kinetic model and Freundlich isotherm model with a maximal monolayer adsorption capacity reached 440.05 mg/g. Notably, after five adsorption runs, the composite maintained its removal efficiency exceeding 74 %. The assumed adsorption mechanisms of Pb2+ onto GO@Fe3O4-i.Carr were complexation, precipitation, Lewis acid-base, and electrostatic attraction forces. Overall, the GO@Fe3O4-i.Carr composite elucidated the auspicious adsorbent criteria, comprising fast adsorption with high performance, ease-separation and tolerable recyclability, advising its feasible use to decontaminate water bodies from hazardous heavy metals.

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Magnetic-assisted DNA testing technology has attracted much attention in genetics, clinical diagnostics, environmental microbiology, and molecular biology. However, achieving satisfying DNA adsorption and desorption efficiency in real samples is still a big challenge. In this paper, a new kind of high-quality magnetic composite microsphere of MM@PGMA-PA-Ti4+ was designed and prepared for DNA extraction and detection based on the strong interaction of Ti4+ and phosphate groups. By taking the advantages of high magnetic susceptibility and high Ti4+ content, the MM@PGMA-PA-Ti4+ microspheres possessed remarkable extraction capacity for mimic biological samples (salmon sperm specimens) with saturated loadings up to 533.0 mg/g. When the DNA feeding amount was 100 µg and the MM@PGMA-PA-Ti4+ dosage was 1 mg, the adsorption and desorption efficiencies were 80 and 90%, respectively. The kinetic and equilibrium extraction data were found to fit well with the pseudo-second-order model and Freundlich isotherm model. Furthermore, the MM@PGMA-PA-Ti4+ microspheres were successfully employed for DNA extraction from mouse epithelial-like fibroblasts. The extraction ability (84 ± 4 µg/mg) and DNA purity were superior to the comparative commercial spin kits, as evaluated by electrophoresis assays and qPCR analysis. The experimental results suggest that the MM@PGMA-PA-Ti4+ microspheres possess great potential as an adsorbent for DNA purification from complex biological samples.

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Liquid Crystal Display (LCD) masking is a 3D printing technique that can produce soft magnetic composite parts to high resolution and complexity for robotics and energy electronics applications. This additive manufacturing technique has the potential to produce larger, lighter-weight, more efficient, and more durable parts for automotive and mechanical applications. This study conducted a binder study to create a low-viscosity and stiff binder capable of loading at least 60 v/v% Fe-6.5 wt%Si particles. Percolation Theory was applied to anticipate the magnetic interaction of suspended particles. A series of binders were formulated, with adjustments to diluent ratios. The behavior of the binders was assessed by studying their rheological properties, conversion rates, and mechanical properties. A post-cure study was conducted across various energy settings using UV, thermal, and a combination of both energy sources to find the combination that provided the best mechanical properties. As a result, 64 v/v% Fe-6.5 wt%Si loading was achieved and cured using UV light of 405 nm wavelength. Vibrating Sample Spectroscopy (VSM) was used to characterize the composite's magnetic behavior, and a significant increase in saturation magnetization and negligible change in coercivity was observed when the added load exceeded the percolation threshold.

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This work presents a novel strategy for the synthesis of a recyclable aerogel and its multifunctional application as effective adsorption material for organic pollutants and as a high-quality SERS substrate for on-site detection measurement. Silver nanoparticles (Ag NPs) were uniformly dispersed and adsorbed on the surface of an Fe3C-loaded carbon aerogel, resulting in the formation of a three-dimensional Ag-Fe3C-MCA (magnetic carbon aerogel) composite. The substrate preparation led to Ag-Fe3C-MCA with a mesoporous structure for high adsorption capacity, together with magnetic properties for easy separation capability. The Ag-Fe3C-MCA composite demonstrated an efficient removal ability for malachite green (MG), with an adsorption capacity of 296.7 mg g-1. Moreover, Ag-Fe3C-MCA composite provided ultrasensitive surface-enhanced Raman scattering detection for MG molecules, obtaining a limit of detection (LOD) of 3 × 10-10 M. Aquaculture water samples with spiked MG concentrations were used to simulate practical scenarios. The Ag-Fe3C-MCA presented has a significant potential for the removal of hazardous residues in wastewater, together with an efficient and sensitive method of quantification, all on the same substrate.

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The present research comprises the fabrication of magnetic Fe3O4 incorporated chitosan grafted acrylamide and N-vinylimidazole composite hydrogels (CANFe-1 to CANFe-7) via water mediated free radical polymerization technique using ammonium persulfate/tetramethyl ethylenediamine as initiator. The prepared magnetic composite hydrogel was characterized by FT-IR, TGA, SEM, XRD, and VSM analysis. A swelling study was performed to understand the swelling behavior and found CANFe-4 to be more efficient with maximum swelling hence entire removal studies were performed with CANFe-4. pHPZC analysis was performed to determine pH sensitive adsorptive removal of cationic dye (methylene blue). pH dependent adsorption of methylene blue was dominant at pH = 8 with a maximum adsorption capacity of 860 mg/g. After the adsorptive removal of methylene blue from aqueous media, a composite hydrogel can conveniently be separated from the solution with the use of an external magnet. Adsorption of methylene blue is well explained with the Langmuir adsorption isotherm and Pseudo-Second-Order kinetic model that validates chemisorption. Moreover, it was found that CANFe-4 could be frequently applied for the adsorptive removal of methylene blue for 5 consecutive adsorption-desorption cycles with 92.4 % removal efficiency. Hence, CANFe-4 offers a promising recyclable, sustainable, robust, and efficient adsorbent for wastewater treatment.

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Fenton-based electrochemical processes (FEPs) using newly engineered 3D photocatalyst nanocomposites have garnered significant attention owing to their ability to remove emerging contaminants. Despite the development of numerous materials, there is still a need to enhance their efficiency, stability, and recyclability to address the limitations of FEPs. This study seeks to address this issue by investigating sustainable methods to engineer novel 3D core-shell photocatalyst composites for application in FEPs. These materials can update the photo-assisted FEPs activity, and magnetism can be helpful for the easy recyclability of the catalyst. Herein, we successfully synthesized a magnetic and photoactive CuFe2O4@MIL-100(Fe) (CM) composite through sustainable methods and assessed its morphological structure and physicochemical and photocatalytic properties. The catalytic performance of CM was investigated in an undivided RuO2/air-diffusion cell to treat Cefadroxil. The results show that heterogeneous photoelectro-Fenton (HPEF) (100% in 120 min) has higher degradation efficiency than electro-Fenton (100% in 210 min) and electrooxidation (73.3% in 300 min) processes. The superior degradation efficiency of HPEF is attributed to the formation of a large amount of hydroxyl radicals indicating the excellent photocatalytic activity of the material due to the direct excitation of the Fe-O cluster, which boosts the redox reaction of Fe2+/Fe3+. Key operational parameters such as pH, catalyst concentration, current density, and CuFe2O4 proportion on MIL-100(Fe) in the composite were optimized in the HPEF process. The optimized composite exhibited good stability and easy recyclability, allowing high removal efficiency, which can be kept up after five cycles of 90 min. High degradation performance was observed using natural sunlight radiations. Additionally, possible catalytic degradation mechanisms in HPEFs were proposed based on radical quenching experiments. This study has significant potential to contribute to the development of more sustainable and effective water treatment strategies.

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