Magnetic Ni Nanoparticles Research Articles

Confined magnetic nickel nanoparticles in carbon microspheres with high-performance electromagnetic wave absorption in Ku-band

Composition and structure regulation is the primary strategy in preparing high-performance electromagnetic (EM) wave absorption materials. Herein, magnetic-dielectric synergy Ni@C microspheres were fabricated to obtain the high-performance electromagnetic (EM) wave absorption performance. Firstly, the Ni-containing precursor microspheres were obtained via the spray-drying technology. Secondly, reduced magnetic Ni nanoparticles (NPs) were confined in the N-doped carbon microspheres after pyrolysis treatment in the H2/Ar atmosphere. Duo to the existence of melamine, the distribution of Ni NPs and related EM parameters of Ni@C microspheres were efficiently regulated to seek the well impedance matching and EM responded ability. As results, as-synthesized Ni@C microspheres exhibited the minimum reflection loss (RLmin) of −48.2 dB and effective absorption bandwidth (EAB) of 5.7 GHz, covering almost Ku-band. This research represents a significant advancement in the development of magnetic-dielectric composite microspheres with superior absorption capacity, and it also provides a large-scale preparation strategy for electromagnetic wave absorbing materials.

Modulating multiple interfaces, defects, and dual-scale interlinked frameworks of cotton-derived spiral CF@Ni@CNT fibers for boosted thermal conduction and microwave absorption

Developing dual-functional materials with excellent thermal conduction and microwave absorption has emerged as a critical strategy for addressing increasingly serious electromagnetic pollution and heat dissipation difficulties. While the advancements in these materials are constrained by their high loading and incompatible performance. To develop a thermally conductive and microwave-absorbing material with a low load, this work fabricates a series of cotton-derived spiral fibers, i.e., carbon fibers (CFs), carbon fiber/Ni (CF@Ni) fibers, and carbon fiber/Ni/carbon nanotube (CF@Ni@CNT) fibers, via a freeze-drying calcination method. By controlling the amount of nickel acetate (n) and methylbenzene volume (V), we finely modulated the multiple heterostructure interfaces, dual-scale interconnected network, defects, and magnetic/dielectric-loss of the spiral CF@Ni@CNT fibers. Results show that the comprehensive properties of spiral CF@Ni and CF@Ni@CNT fibers, obtained by combining spiral CFs with magnetic Ni nanoparticles and/or CNTs, are significantly improved. The spiral CF@Ni fibers formed at n = 8.4 mmol exhibit a lower thermal conductivity (TC = 3.64 W/m⋅K) but a wider absorption bandwidth (EAB = 6.4 GHz; 10 wt% load) than CFs. Besides, the spiral CF@Ni@CNT fibers formed at n = 4.2 mmol and V = 2 mL bear a higher TC (4.27 W/m⋅K) and a larger EAB (7.52 GHz/mm) at the same load (10 wt%). The low load could be ascribed to the low percolation threshold of a dual-scale interconnected framework consisting of CFs, CNTs, and Ni0. Additionally, the simultaneous improvement in thermal conduction and microwave absorption of the spiral CF@Ni@CNT fibers is associated with their magnetic-dielectric dual loss, electron-phonon co-transmission, and dual-scale interconnected framework.

Nickel-doped magnetic carbon aerogel derived from xanthan gum: a competent catalyst for the degradation of single and binary dye-based water pollutants.

Toxic organic dyes (colorants) are one of the main causes of water pollution that releases destructive effluents in the environment. To overcome this issue, a fundamental need to produce a novel, efficient catalyst for the degradation and mineralization of dye mixtures has arisen. The objective of this research is to develop an eminent Ni-doped magnetic carbon aerogel (Ni-MCA) catalyst using graft co-polymerization method having xanthan gum as backbone doped with Ni-magnetic nanoparticles (Ni-MNPs), that do not show agglomeration and easy to separate. The examination revealed that Ni-MCA provided exceptional magnetic characteristics (Ms = 52.75emu/g) and potent catalytic activity for the degradation of mono- as well as binary-dye solutions of Congo red (CR) and methyl green (MG) dyes. The formation was verified by various characterization techniques such as FTIR, VSM, XRD, XPS, SEM, TEM, and EDX mapping. Interestingly, Ni-MCA shows faster result on anionic dye CR up to 97% with degradation rate of 5.647 × 10-1min-1, and MG dye shows degradation of 95.7% with the degradation rate of 2.169 × 10-1min-1, while dye mixture is showing 90% degradation with rate of 2.159 × 10-1min-1.

Studies on the structural and magnetic properties of PMMA/Ni nanocomposite system prepared by embedding Ni nanoparticles in the PMMA films

PMMA/Ni nanocomposite films have been prepared by embedding Ni nanoparticles and maintaining their different thickness (5–50 nm) in PMMA (polymethylmethacrylate) film matrix by using ion beam sputtering (IBS) technique. Grazing incidence x-ray diffraction (GIXRD) results reveal Ni is present in metallic form in the FCC phase. X-ray reflectivity (XRR) is used to measure the nominal thickness of the Ni nanoparticle layer. Surface morphology was studied using atomic force microscopes (AFM). SXAS (soft x-ray absorption spectroscopy) studies on PMMA/Ni nanocomposites were done using synchrotron radiation to understand the electronic structure of these films which reveals that Ni is present in metallic state confirming that PMMA as host matrix protects the magnetic Ni nanoparticles from external oxidation. The magneto-optical Kerr effect (MOKE) magnetometer and MOKE microscope were employed to study the magnetic properties and simultaneously record the real time evolution of magnetic domains at 0°, 45°, and 90° azimuthal angles. All films show soft ferromagnetic behaviour and all the films show isotropic behaviour except one with Ni nanoparticle layer thickness of 40 nm. MOKE micrographs witness the gradual growth of magnetic domains with increase in thickness of Ni nanoparticle layer. These PMMA/Ni nanocomposite films may be viewed as potential candidate for futuristic functional material.

Construction of ZnO/Ni@C hollow microspheres as efficient electromagnetic wave absorbers with thin thickness and broad bandwidth

Ingenious microstructure design and rational composition collocation have been proved to be an effective strategy for developing efficient electromagnetic wave (EMW) absorbers. It would be promising to fabricate a hollow structured composite integrating multiple loss mechanisms (conduction, magnetic, and polarization losses) for excellent EMW absorption. Herein, a novel dielectric-magnetic compound of ZnO/Ni@C hollow microsphere was prepared through hydrothermal reactions followed by an in-situ chemical vapor deposition (CVD). In this ternary composite, abundant ZnO/Ni heterostructures formed the hollow microsphere skeletons and provided unique Schottky junctions, which endowed the composite with improved impedance matching and strong polarization loss. Meanwhile, the amorphous-polycrystalline carbon layer deposited on the surface of each microsphere enhanced the conduction and interfacial polarization losses. In addition, the magnetic Ni nanoparticles induced magnetic loss. Benefiting from the synergistic effect of the hollow structure and multiple loss mechanisms, the ternary composite exhibits an effective absorption bandwidth as wide as 6.55 GHz at a thickness of only 1.85 mm, accompanied by a minimum reflection loss of –39.8 dB. Besides, the radar cross-section and the electromagnetic field simulation further verify the superior EMW absorption performance of the composites. Our work provides a new reference for the fabrication of dielectric-magnetic ternary hollow microspheres as EMW absorbers with thin thickness and broad bandwidth.

Ni-Carbon Microtube/Polytetrafluoroethylene as Flexible Electrothermal Microwave Absorbers.

Flexible microwave absorbers with Joule heating performance are urgently desired to meet the demands of extreme service environments. Herein, a type of flexible composite film is constructed by homogeneously dispersing a hierarchical Ni-carbon microtube (Ni/CMT) into a processable polytetrafluoroethylene (PTFE) matrix. The Ni/CMT are interconnected into a 3D conductive network, in which the huge interior cavity of thecarbon microtube (CMT) improves impedance matching and provides additional hyper channels for electromagnetic (EM) waves dissipation, and the hierarchical magnetic Ni nanoparticles enhance the synergistic interactions between confined heterogeneous interfaces. Such an ingenious structure endows the composites with excellent electrothermal performance and improves their serviceability for application under extreme environments. Moreover, under a low fill loading of 3wt.%, the Ni/CMT/PTFE (NCP) can achieve excellent low-frequency microwave absorption (MA) property with a minimum reflection loss of -59.12dB at 5.92GHz, which covers almost the entire C-band. Relying on their brilliant MA property, an EM sensor is designed and achieved by the resonance coupling of the patterned NCP. This work opens up a new way for the design of next-generation microwave absorbers that meet the requirements of EM packaging, proofing water and removing ice, fire safety, and health monitoring.

Design of 3D graphene‐Ni microsphere based polymeric composites for highly efficient and absorption‐dominated electromagnetic interference shielding performance

AbstractThe development of polymeric composites that possess both exceptional electromagnetic interference shielding effectiveness (EMI SE) and high absorption capacity has always been appealing, yet it continues to pose a significant challenge. To this end, we disclose a hollow and spherical shielding unit that could achieve “absorption‐reflection‐attenuation” process for incident electromagnetic (EM) wave, which was fabricated through decorating Ni nanoparticles onto rGO hollow microspheres by virtue of Pickering emulsification method followed by thermal annealing. With integrated magnetic and electric parts, the consequent shielding composite by assembling these microspheres into PDMS displayed not only a favorable EMI SE of 44 dB across the entire x‐band, but also significantly improved absorption performance that has exceeded 95% of the total SE. Moreover, the power coefficient of absorption (A) is up to 0.73 at the pyrolysis temperature of 550°C. Such admirable performance is mainly attributed to the synergistic effect of conductive rGO walls, magnetic Ni nanoparticles, as well as the unique spherical architecture, which has enabled more efficient capture and attenuation of EM waves. Herein, this research has highlighted the development of polymeric composites for high‐performance EMI shielding applications.Highlights Reflection‐absorption‐integrated shielding compartment was designed. Decorating magnetic Ni nanoparticles onto rGO hollow microspheres. High EMI SE with enhanced absorption ability was acquired. Unique structure generating synergistic effect on EMI shielding

Lotus Leaf Derived NiS/Carbon Nanofibers/Porous Carbon Heterogeneous Structures for Strong and Broadband Microwave Absorption.

Developing composite materials with the synergistic effects of heterogeneous structures and multiple components is considered as a promising strategy to achieve high-performance electromagnetic wave (EMW) absorbers. To further satisfy the demand of broadband and strong microwave absorption, a novel NiS/carbon nanofibers (CNFs)/porous carbon composite is successfully synthesized by hydrothermal and chemical vapor deposition using lotus leaves as a biomass carbon source. A few carbon nanotubes (CNTs) and uniformly dispersed Ni nanocrystals have also been found in the hybrid. Benefiting from the porous structure derived from lotus leaves, the combination of dielectric NiS, conductive carbon nanomaterials, and magnetic Ni nanoparticles, together with the three-dimensional conductive network of CNFs and CNTs, the remarkable EMW absorption properties with a minimum reflection loss up to -67.65 dB have been achieved at merely 2.32 mm. Besides, the widest effective absorption band can reach 5.9 GHz with a thin thickness of 2.07 mm, covering almost the entire Ku band. In addition, under the incident angle of 31°, the radar cross-section reduction value of LNSF-600 can reach 42.88 dBm2. Therefore, this work provides an efficient and facile method for manufacturing outstanding biomass-derived EMW absorbers.

In-situ growth of magnetic nanoparticles on honeycomb-like porous carbon nanofibers as lightweight and efficient microwave absorbers

To achieve the goal of both lightweight and strong absorption, tailoring the microstructure and components of microwave absorber had been regarded as a promising method. Herein, in-situ growth of magnetic Ni nanoparticles on honeycomb-like porous carbon nanofibers were prepared by electro-blowing spinning and subsequent high-temperature pyrolysis technique. The honeycomb-like porous structure of carbon nanofibers was formed by the decomposition of pore forming agent PTFE nanoparticles during carbonization process, and the effects of PTFE content on the specific surface area and pore size distribution were systematically studied. Simultaneously, the magnetic Ni nanoparticles were in-situ formed and homogenously dispersed in the fiber skeleton. The obtained fibers were connected into a three-dimensional (3D) interconnected macroscopic network, which could form an electrically conductive network to enhance the conductive loss, and induce multiple reflecting and scattering to consume electromagnetic waves. The honeycomb-like porous structure with large specific surface area could shorten the impedance gap with free space and endow the absorber with light-weight feature. In addition, the in-situ growth magnetic Ni nanoparticles introduced additional magnetic loss, which was also benefit to improve the impedance matching. Moreover, the formed heterojunctions at the interface of magnetic Ni nanoparticles and carbon nanofibers triggered intensive interfacial polarization. Under the synergistic effect of magnetic-dielectric loss, appropriate impedance matching, strong interfacial polarization and multiple reflecting and scattering, the optimal sample of Ni/PCNF-2 presented an excellent microwave absorption performance with the minimum RL of −40.48 dB at 1.5 mm thickness, and the effective absorption bandwidth reached to 4.0 GHz.

In Situ Fabrication of Magnetic and Hierarchically Porous Carbon Films for Efficient Electromagnetic Wave Shielding and Absorption.

Carbon-based materials have been recognized as a promising method to eliminate electromagnetic interference (EMI) shielding and electromagnetic (EM) wave absorption. However, developing lightweight, ultrathin, and efficient EM wave-shielding and wave-absorbing materials remains a challenge. Herein, a series of magnetic porous carbon composite films with a hierarchical network structure were fabricated via pyrolysis of porous polyimide (PI) films containing magnetic metallic salts of Fe(acac)3 and Ni(acac)2. After pyrolysis, the obtained uniform porous carbon films (CFs) possess a favorable EMI-shielding efficiency (SE) of 46 dB in the X-band with a thickness of ∼0.3 mm. In addition, a higher EMI SE of 58 dB can be achieved by increasing the thickness of the porous CF-20Ni to 0.53 mm. Moreover, the CF-20Ni composites also present effective EM wave-absorbing performance of RLmin = - 30.2 dB with a loading amount of 20 wt % at 13.0 GHz owing to the hierarchically conductive carbon skeleton, magnetic Ni nanoparticles, and dielectric interlaced carbon nanotube cluster within the micropores. These novel lightweight and ultrathin porous CFs are expected to be attractive candidates for efficient EM wave absorption and EMI shielding.

Facile Synthesis of MOF‐Derived One‐Dimensional Nitrogen‐doped Carbon/Ni Composites and their Application as Catalysts and Protein Adsorbents

AbstractMetallic nickel is of particular interest because of its low cost, magnetic property, and multifunctional uses. Herein, a facile strategy to fabricate one dimensional(1D) carbon microrods with magnetic Ni nanoparticles(NPs) by one‐step carbonization of nickel‐ion‐nitrilotriacetic acid coordination polymer microrods (Ni‐NTA) has been presented. After the carbonization, the original morphology of Ni‐NTA microrods is preserved well. Fine magnetic Ni NPs are well dispersed in the carbon matrix, which possesses an impressive saturation capacity for Histidine‐rich protein, BHb. Moreover, such N‐doped carbon microrods with well‐dispersed Ni NPs on its surface present an excellent catalytic performance and stability by using the reduction of 4‐nitrophenol as a model reaction. Notably, the selected Ni‐NTA microrods and melamine act as Ni‐precursor and N‐doped carbon sources play a vital role in the formation of 3D hierarchical carbon dendrites composed of carbon microfiber trunks and carbon nanotube branches.

Magnetically separable Ni/g-C3N4 nanocomposites for enhanced visible-light photocatalytic degradation of methylene blue and ciprofloxacin

To develop a highly efficient and easily recyclable photocatalysts, graphitic carbon nitride (g-C3N4) nanosheets were hydrothermal synthesized firstly and then magnetic Ni nanoparticles were anchored on g-C3N4 nanosheets with solvothermal method. The morphology, microstructures, magnetic response and photocatalytic activity of all samples were characterized with XRD, TEM, VSM, N2 adsorption–desorption isotherms and spectrophotometer. All results indicate that Ni nanoparticles anchor on the surface of g-C3N4 nanosheets to form Ni/g-C3N4 nanocomposites. The g-C3N4 nanosheets present the higher photocatalytic activity than pristine g-C3N4 powders. The photocatalytic activities to MB and CIP of Ni/g-C3N4 nanocomposites are much higher than those of g-C3N4 nanosheets. The interface between Ni and g-C3N4 forms the metal-semiconductor heterojunctions, which plays a dominated role on electron transition near interface. The photogenerated electrons near interface prefer to transfer from g-C3N4 nanosheets to Ni nanoparticles, resulting in the separation of photogenerated electron-hole pairs. Furthermore, Ni/g-C3N4 nanocomposites could be easily separated from the solution after photocatalysis.

Facile manufacturing of Ni/MnO nanoparticle embedded carbon nanocomposite fibers for electromagnetic wave absorption

A type of nickel/manganese oxide (Ni/MnO)/carbon nanocomposite fibers were prepared via a facile and scalable electrospinning and carbonization approach. In comparison to the pure carbon showing a severe agglomeration, the uniformly embedded MnO and Ni nanoparticles promoted the formation of the fibrous carbon-based nanocomposites with an average diameter of 250 nm and a rough surface. The synergistic coactions of the MnO nanoparticles acting as impedance modulating mediator, the magnetic Ni nanoparticles, and the conductive, fibrous carbon with large aspect ratio and rough surface contributed to the excellent electromagnetic wave (EMW) absorbing performance of the nanocomposites. The nanocomposites with a MnO/Ni ratio of 1:1 exhibited an effective absorption bandwidth of 6.5 GHz at a thickness of 2.9 mm and a minimum reflection loss of −53.23 dB at a thickness of 2.3 mm. The EMW absorption mechanisms of the nanocomposite fibers were discussed at length, which showed the importance of the multi-component building units and microstructure for achieving high EMW absorbing performance. This work thus suggested a convenient, facile, and scalable manufacturing approach for constructing high-performance multi-component nanocomposite fiber based EMW absorbing materials.

Non-conventional superconductivity in magnetic In and Sn nanoparticles

We report on experimental evidence of non-conversional pairing in In and Sn nanoparticle assemblies. Spontaneous magnetizations are observed, through extremely weak-field magnetization and neutron-diffraction measurements, to develop when the nanoparticles enter the superconducting state. The superconducting transition temperature TC shifts to a noticeably higher temperature when an external magnetic field or magnetic Ni nanoparticles are introduced into the vicinity of the superconducting In or Sn nanoparticles. There is a critical magnetic field and a critical Ni composition that must be reached before the magnetic environment will suppress the superconductivity. The observations may be understood when assuming development of spin-parallel superconducting pairs on the surfaces and spin-antiparallel superconducting pairs in the core of the nanoparticles.

Thickness-controllable synthesis of MOF-derived Ni@N-doped carbon hexagonal nanoflakes with dielectric-magnetic synergy toward wideband electromagnetic wave absorption

Heteroatom nitrogen doping and morphology control have been considered as the effective approaches for improving electromagnetic wave (EMW) absorption ability of carbon-based absorbers. Herein, by controlling the adding dosage of pyridine, thickness controllable MOF-derived Ni@N-doped carbon (Ni@NC) hexagonal nanoflakes presented increased content of doped N atoms and tunable morphology from nanorods-, nanoparticles- to nanoflakes-like. Moreover, it made it possible to adjust the electromagnetic parameters of Ni@NC. The 3D conductive network of carbon framework and magnetic Ni nanoparticles could be obtained from the converted MOF precursor. The controllable dimension and morphology of N-doped carbon skeleton endowed more electronic transportation paths, better anti-reflection surfaces, higher conduction loss and polarization relaxation, while the evenly distributed Ni nanoparticles provided considerable multiple resonances and eddy current. All of these characteristics contributed the electromagnetic wave absorption (EMA) with improved dielectric loss, magnetic loss and impedance matching. The analysis indicated that the sample with 30 wt% of Ni@NC-nf showed the widest bandwidth, which was 6.21 GHz ranging from 11.79 to 18.00 GHz with a thickness of 2.3 mm, while the corresponding radar band was the whole Ku band (12.0–18.0 GHz). Our research provided a valuable approach for fabricating high-efficiency microwave absorption materials by combining the control of morphology and N-doped effect on the absorbers.

Magnetic mesoporous carbon nanosheets derived from two-dimensional bimetallic metal-organic frameworks for magnetic solid-phase extraction of nitroimidazole antibiotics

We prepared two-dimensional (2D) bimetallic metal-organic frameworks (Ni-ZIF-8) nanosheets by a simple solvent-free method at room temperature. The morphology and composition of Ni-ZIF-8 can be controlled through adding different amounts of Ni. And then, the 2D magnetic mesoporous nanosheets (Ni/ZnO@C) were synthesized by directly pyrolyzing Ni-ZIF-8 under argon atmosphere and explored as magnetic solid phase extraction (MSPE) adsorbents for the determination of nitroimidazole antibiotics (NIABs). Magnetic Ni nanoparticles embedded in carbon nanosheets uniformly resulted in high magnetization saturation of Ni/ZnO@C for easy separation. The Ni/ZnO@C can form hydrogen bond and π-π interaction with three NIABs resulting from their rich N-H containing imidazole, π-electron. Due to the high specific surface area and high mass transfer rate of 2D Ni/ZnO@C, the materials showed satisfactory adsorption capacity and rapid adsorption kinetics for NIABs. A rapid and effective method of Ni/ZnO@C-MSPE combined with high-performance liquid chromatography was proposed for the determination of NIABs. Several main parameters affecting MSPE were investigated. Under the optimal conditions, wide linear was achieved ranging from 0.1 to 500 µg⋅L−1 with a low detection limit of 0.025-0.05 µg⋅L−1. The established method has been successfully applied to analyze NIABs from environmental water samples with satisfactory recovery from 74.33 to 105.71%.

Dielectric and mechanical properties of nickel silica core-shell reinforced PMMA nanocomposites

This paper study the dielectric and mechanical properties of poly (methyl methacrylate)-nickel silica core-shell nanocomposite. Ni@SiO2/PMMA nanocomposite films were prepared by incorporating Ni@SiO2nanoparticles in PMMA matrix using the solution casting method. The morphology of the prepared nanoparticles was examined through a High-resolution transition electron microscope (HRTEM), which revealed the formation of SiO2shell at Ni magnetic nanoparticles. The dielectric properties of the nanocomposite films were studied as a function of temperature and frequency in the ranges of 30–180°C and 100 Hz – 5 MHz respectively. The incorporation of the nano Ni@SiO2to PMMA has a positive effect on the dielectric constant ε′ of the nanocomposites, as well as, ε′ improved with increasing temperature. The real electric modulus (M′) of composites confirms the occurrence of dispersion in all composites at all temperatures. While dielectric loss tangent ε ″ and the loss part of electric modulus spectra (M) exhibit relaxation peaks which characterize possible relaxation of interfacial polarization in the interface between Ni@SiO2core-shell and PMMA matrix, these peaks have shifted towards higher frequency with temperature. The relaxation and activation energies, Ecand Eavalues decreased from 0.49 to 0.40 eV and from 0.87 to 0.70 eV respectively as Ni@SiO2content increased. The ac conductivity of the nanocomposite films has deeply increased with increasing temperature and Ni@SiO2content. The longitudinal modulus (L), shear modulus (G), Young's modulus (E), and bulk modulus (B) of films were studied and they increased as the filler increased from 0 to 15 wt.%.

Gamma-radiation induced synthesis of freestanding nickel nanoparticles.

A versatile method to produce metallic nickel nanoparticles is demonstrated. Metallic Ni nanoparticles have been synthesized from aqueous solution of NiCl2 using γ-radiation induced reduction. To prevent Ni re-oxidation, post-irradiation treatment was elaborated. Structural and compositional analyses were executed using X-ray diffraction, transmission electron microscopy and X-ray photoelectron spectroscopy. These studies reveal that the synthesized material consists of fcc Ni particles having size of 3.47 ± 0.71 nm. The nanoparticles have a tendency to agglomerate to the larger clusters. The latter are partially oxidized to form thin amorphous/poor-crystalline Ni(OH)2/NiO layers at the surface. Magnetization measurements demonstrate that the nanomaterial exhibit ferromagnetic-like behaviour with magnetization 30% lower than that in bulk Ni. The large active surface area (ECSA, 39.2 m2 g-1) and good electrochemical reversibility, confirmed by the electrochemical studies, make the synthesized material a potential candidate as an active component for energy storage devices.

Nano-sized magnetic Ni particles based dispersive solid-phase extraction of trace Cd before the determination by flame atomic absorption spectrometry with slotted quartz tube: a new, accurate, and sensitive quantification method.

In this study, a new analytical strategy was developed to determine trace cadmium in aqueous samples with high sensitivity and accuracy. A combination of magnetic nickel nanoparticles (Ni-MNPs) based dispersive solid-phase extraction (DSPE) and flame atomic absorption spectrometry fitted with a slotted quartz tube (SQT-FAAS) lowered the detection limit of cadmium. The magnetic Ni nanoparticles were synthesized, characterized, and thoroughly optimized in a stepwise approach. The quartz tube was custom cut in the laboratory to suit the specifics of the flame burner. Using the optimized conditions, a limit of detection value of 0.58 μg/L and limit of quantification value of 1.93 μg/L were obtained. To demonstrate accuracy and applicability of the developed method, well water samples were analyzed for their Cd content, and matrix effect on the extraction yield was investigated. The percent recovery results calculated ranged from 93.8 to 108.2%, with corresponding standard deviation values ranging from 1.7 to 7.7. These results established the developed method as sensitive, accurate, and precise for determination of cadmium at trace levels.

Lightweight and Hydrophobic Three-Dimensional Wood-Derived Anisotropic Magnetic Porous Carbon for Highly Efficient Electromagnetic Interference Shielding.

Constructing multifunctional characteristics toward advanced electromagnetic interference shielding materials in harsh environments has become a development trend. Herein, the wood-derived magnetic porous carbon composites with a highly ordered anisotropic porous architecture were successfully fabricated through a pyrolysis procedure. The three-dimensional porous skeleton inherited from the wood stock serves as an electrically conductive network and incorporates magnetic Ni nanoparticles homogeneously and firmly embedded within the carbon matrix that can further improve the electromagnetic attenuation capacity. The optimized Ni/porous carbon (PC) composite exhibits an exceptional electromagnetic interference (EMI) shielding effectiveness of 50.8 dB at the whole X band (8.2-12.4 GHz) with a low thickness (2 mm) and an ultralow density (0.288 g/cm3) and simultaneously possesses an extraordinary compressive strength (11.7 MPa) and a hydrophobic water contact angle (152.1°). Our study provides an alternative strategy to utilize green wood-based materials to design multifunctional EMI shielding composites.