Magnetic Composite Microspheres Research Articles

Carboxyl-Assisted Coordination-Driven Self-Assembly for the Preparation of Magnetic Polymer Composite Microspheres

Carboxyl-Assisted Coordination-Driven Self-Assembly for the Preparation of Magnetic Polymer Composite Microspheres

Fabrication of Monodisperse Magnetic Polystyrene Mesoporous Composite Microspheres for High-Efficiency Selective Adsorption and Rapid Separation of Cationic Dyes in Textile Industry Wastewater.

Sustainable development has become an inevitable trend in the world's green chemical industry for a generation or more. In this study, a monodisperse magnetic polystyrene mesoporous composite microsphere (MPPS) composed of Fe3O4 nanoparticles loaded on polystyrene mesoporous microspheres is introduced. These microspheres serve as effective adsorbents for the swift removal of cationic dyes. The fabrication of the wastewater adsorbent, with its simple operation and economic practicality, involved a combination of dispersion polymerization, a sulfonation reaction, two-step swelling polymerization, and in situ alkaline oxidation technology. Notably, the adsorption capacity within 3 min reaches 184.0 mg/g, with an impressive adsorption efficiency of 92%. This is primarily attributed to the high specific surface area (Smax) of the MPPS providing more reaction sites for π-π interaction. Simultaneously, the attractive force between negatively charged sulfonic acid groups and cationic dyes is enhanced through surface modification of the MPPS. Furthermore, the MPPS, boasting a maximum saturation magnetization of 38.19 emu/g, ensures rapid separation from the solution for recycling within 3 s. Even after 5 cycles, the adsorption efficiency remains over 90%. The rapid separation of dyes is facilitated by the magnetic attraction of Fe3O4 nanoparticles from the MPPS under the application of a magnetic field. These composite mesoporous materials exhibit outstanding performance in both efficient selective adsorption and recyclability, presenting a novel green adsorbent with promising prospects for sustainable development. This innovation is poised to excel in fields such as sewage treatment, separation, and purification.

Fabrication and characterization of graphene oxide (GO)-modified micro-nano composite magnetic microspheres

Addressing the contradiction between the magneto-rheological properties and dispersion stability of MRFs poses a significant challenge in the preparation process. This paper proposes a micro-nano composite material design scheme using graphene oxide as a grafting agent to encapsulate nanoscale magnetite (Fe3O4) particles onto the surface of carbonyl iron powders. The prepared micro-nano composite magnetic microspheres achieve a reduction in density for enhanced stability while ensuring no compromise in magnetic performance. The effectiveness of the preparation process is ensured through the analysis of the microscopic morphology, crystal structure, and elemental characteristics of all process products using Field Emission Scanning Electron Microscopy (FE-SEM), powder X-ray diffraction (XRD), Raman Spectroscopy, and Fourier Transform Infrared Spectroscopy (FTIR). To obtain MRFs more suitable for magneto-rheological damper applications, this study synthesized micro-nano composite MRFs with different base liquids and varying volume fractions. The stability and magneto-rheological properties of each sample were analyzed through visual techniques and rheological testing platforms. The results indicated that micro-nano composite MRFs based on 40% to 50% silicone oil exhibit superior stability in various aspects, including sedimentation stability, redispersion stability, and temperature stability. Additionally, the micro-nano composite MRFs demonstrated significantly enhanced magnetic performance compared to pure micrometer-sized, pure nanometer-sized, and micro-nano hybrid MRFs.

Preparation of magnetic DTPA-modified chitosan composite microspheres for enhanced adsorption of Pb(II) from aqueous solution

In this study, magnetic DTPA-modified chitosan composite microspheres (MDCM) were prepared by reverse emulsion-double crosslinking method (carbodiimide followed by glutaraldehyde) for removal of Pb(II) from aqueous solution. The obtained magnetic adsorbents were characterized by FTIR, SEM, XRD, VSM, BET, and 13C NMR. The effects of the pH, contact time, initial concentration, and competitive metal cations (Na(I), Ca(II), or Mg(II)) on Pb(II) adsorption were investigated. The results revealed that MDCM exhibited high removal performance over a wide pH range and in the presence of competitive metal cations. The maximum adsorption capacity of MDCM for Pb(II) is 214.63 mg g−1 at pH 3, which is higher than most recently reported magnetic adsorbents. Adsorption kinetics and isotherms can be described by the pseudo-second-order model and Langmuir model, respectively. In addition, MDCM is easy to regenerate and can be reused five cycles with high adsorption capacity. Finally, the adsorption mechanism was further revealed by FTIR and XPS analysis. Overall, MDCM has practical application potential in removing Pb(II) from contaminated wastewater due to its high adsorption efficiency, good reusability, and convenient magnetic separation.

A novel alginate-embedded magnetic biochar-anoxygenic photosynthetic bacteria composite microspheres for multipollutant removal: Mechanisms of photo-bioelectrochemical enhancement and excellent reusability performance

Existing wastewater treatment technologies face the key challenge of simultaneously removing emerging contaminants and nutrients from wastewater efficiently, with a simplified technological process and minimized operational costs. In this study, a novel alginate-embedded magnetic biochar-anoxygenic photosynthetic bacteria composite microspheres (CA-MBC-PSB microspheres) was prepared for efficient, cost-effective and one-step removal of antibiotics and NH4+-N from wastewater. Our results demonstrated that the CA-MBC-PSB microspheres removed 97.23% of sulfadiazine (SDZ) within 7 h and 91% of NH4+-N within 12 h, which were 21.23% and 38% higher than those achieved by pure calcium alginate-Rhodopseudomonas palustris microspheres (53% and 45.7%), respectively. The enhanced SDZ and NH4+-N removal were attributed to the enhanced photoheterotrophic metabolism and excretion of extracellular photosensitive active substances from R. Palustris through the photo-bioelectrochemical interaction between R. Palustris and magnetic biochar. The long-term pollutants removal performance of the CA-MBC-PSB microspheres was not deteriorated but continuously improved with increasing ruse cycles with a simultaneous removal efficiency of 99% for SDZ and 92% for NH4+-N after three cycles. The excellent stability and reusability were due to the fact that calcium alginate acts as an encapsulating agent preventing the loss and contamination of R. palustris biomass. The CA-MBC-PSB microspheres also exhibited excellent performance for simultaneous removal of SDZ (89% in 7 h) and NH4+-N (90.7% in 12 h) from the secondary effluent of wastewater treatment plant, indicating the stable and efficient performance of CA-MBC-PSB microspheres in practical wastewater treatment.

Magnetic composite microspheres with a controlled mesoporous shell for highly efficient DNA extraction and fragment screening.

Rapid extraction and screening of high-purity DNA fragments is an indispensable technology in advanced molecular biology. In this article, mesoporous magnetic composite microspheres (MSP@mTiO2) with tunable pore sizes were successfully fabricated for high-purity DNA extraction and fragment screening. Owing to the strong complexation ability of Ti ions with DNA phosphate groups and the high specific surface area of mesoporous microspheres, the MSP@mTiO2 microspheres possess excellent adsorption performance, where the saturated loading capacity of MSP@mTiO2 with a specific surface area of 122 m2 g-1 is as high as 575 μg mg-1 for a salmon sperm specimen. ITC experiments demonstrated that DNA adsorption on MSP@mTiO2 microspheres is mainly driven by entropy, which gives us more potential ways to regulate the balance of adsorption and desorption. Meanwhile, the mesoporous MSP@mTiO2 microspheres exhibit a much higher extraction efficiency compared with non-porous MSP@TiO2 for whole genome DNA from Arabidopsis thaliana plants. Interestingly, DNA fragments with different lengths could be screened by simply regulating the pore size of MSP@mTiO2 or the concentration of Na3PO4 in the eluent. A small pore size and low phosphate concentration are advantageous for the extraction of short-stranded DNA fragments, and DNA fragments (≤1000 bp) can be efficiently extracted when the mesopore size of MSP@mTiO2 is lower than 7.6 nm. The extraction results from the mesoporous composite microspheres provide new promising insights into the purification and screening of DNA from complex biological samples.

A chemiluminescence immunosensor for biomarker detection based on boronic acid-modified magnetic composite microspheres.

High-sensitivity detection of biomarkers in biological samples is crucial for the early diagnosis and treatment of diseases. In this paper, a versatile and flexible immobilization technique based on the specific affinity interaction between boronic acid and cis-diol groups of antibodies was developed for biomarker detection. As a model, the boronic acid-modified immunomagnetic beads were used for facile and quick immobilization of the alpha-fetoprotein (AFP) antibody due to the specific affinity interactions. Based on this new class of immunomagnetic beads, the chemiluminescence immunosensor could efficiently detect the biomarker of AFP. Under optimal conditions, the limit of detection (LOD) is as low as 8 fM (S/N = 3), showcasing superior sensitivity and detection specificity for AFP. Subsequently, the system was successfully applied to the detection of AFP in fetal bovine serum samples, and the average recovery rate is greater than 95%. Its performance surpassed that of commercial immunomagnetic beads, showcasing the potential application of this new strategy for bioanalysis and clinical diagnosis.

Multi-principles analysis of Cu(II) adsorption in water on magnetic microspheres and modified Chitosan

In this study, magnetic composite microspheres (SCFP) were prepared by cross-linking chitosan (CS), sodium alginate (SA), poly(vinyl alcohol) (PVA), and ferric tetraoxide (Fe3O4) in a CaCl2 solution. CS and Fe3O4 were encapsulated in gel spheres formed by cross-linking SA with Ca(II), while PVA facilitated the dispersion of CS in SA. SCFP was utilized as an adsorbent to remove Cu(II) from water. The effects of the initial pH of the solution, SCFP dosage, and initial Cu(II) concentration on the adsorption efficiency were investigated through batch experiments. The results demonstrated that the adsorption capacity reached 58.260 mg/g (removal rate = 97.1%) after 100 min of adsorption at a pH of 5. The removal rate remained above 90% even after 6 cycles of the cycling experiment. The incorporation of CS with other functional materials allowed SCFP to compensate for its inherent drawbacks such as low mechanical strength, poor acid resistance, and short service life. The pseudo-first-order kinetic model and Freundlich adsorption isotherm provided better descriptions of the adsorption process. A comprehensive analysis was conducted on the structure and adsorption mechanism of SCFP using characterization techniques such as SEM-EDS, FTIR, BET, XRD, etc. In summary, SCFP has the potential to be an excellent environmentally friendly material for the removal of Cu(II).

Immobilization of Multivalent Titanium Cations on Magnetic Composite Microspheres for Highly Efficient DNA Extraction and Amplification.

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.

Functionally constructed magnetic-dielectric mineral microspheres for efficient thermal energy storage and microwave absorption

Electromagnetic interference (EMI) and equipment heat dissipation problems are becoming increasingly prominent in advanced applications such as modern wireless communications, driverless cars, and portable devices. Multifunctional composites with efficient energy storage, conversion, and microwave absorption are urgently needed. We reported an effective strategy to construct attapulgite (ATP), carbon nanotubes (CNT), and NiCo alloys composite mineral microspheres (ACNC). Urchin-like TiO2 was coated on the surface of ACNC to form composite microspheres (ACNCT), which was compounded with paraffin (P-ACNCT) to prepare thermal energy storage and microwave absorption integrated material. The urchin-like TiO2 morphology possesses unique advantages in encapsulating paraffin. The results show that the melting and solidification enthalpy of the P-ACNCT reaches 111.6 J/g and 108.1 J/g, respectively, which indicates excellent thermal energy storage capacity. Combining a dielectric TiO2 shell with a magnetic composite microsphere core can produce a core–shell microsphere mechanism that allows for adjustable reflection loss and promotes impedance matching. The effective microwave absorption bandwidth of P-ACNCT can reach 5.76 GHz when the thickness is only 1.6 mm in the 2–18 GHz range. P-ACNCT is significant for synchronous microwave absorption and thermal energy regulation of advanced electronic equipment.

Rough Surface Enhanced Interfacial Synthesis of Core‐Shell Magnetic Fluorescent Microspheres for Enhanced Latent Fingerprint Visualization

AbstractDeveloping latent fingerprints is extremely significant for personal identification and criminal investigation. Sub‐micrometer core‐shell structured magnetic fluorescent composite which combines the merits of noncontact magnetic responsiveness and strong fluorescence emission is highly desired for the visualization of latent fingerprint on various substrates with high resolutions. However, it remains a great challenge to synthesize uniform magnetic fluorescent composites with well‐defined structure and functionalities due to the uncontrollable heterogeneous growth. Herein, a urea‐assisted rough interface precipitation method is proposed to controllably synthesize uniform core‐shell structured magnetic fluorescent composite microspheres (Fe3O4@mesoSiO2@Y2O3:Eu3+). The composite microspheres with magnetic core and mesoporous silica shell (Fe3O4@mesoSiO2) possess huge guest‐host interface, numerous nucleation sites, and rough surface morphology, facilitating the efficient adsorption of Y3+/Eu3+ ions, and further controllable interface deposition of metal (Y, Eu) hydroxides induced by slow release of OH− and CO32− anions via the in‐solution decomposition of urea. After subsequent thermal annealing, the obtained Fe3O4@mesoSiO2@Y2O3:Eu3+ microspheres possess high magnetization for convenient magnetic manipulation, strong fluorescence intensity and negligible quenching effect, enabling a superior performance in latent fingerprint visualization with high contrast and resolution on various substrates.

Fabrication of efficient, magnetic graphene oxide nanocomposite for the enhanced photodegradation of organic dyes under visible light

This study reports magnetic graphene oxide composite microspheres (MGO) were firstly synthesized via one step miniemulsion polymerization. α-FeOOH rods were then loaded onto MGO via a facile hydrothermal method to prepare α-FeOOH@MGO, which was served as the photocatalyst for the Fenton reaction. Subsequently, the properties of the resulting α-FeOOH@MGO were characterized by FT-IR, XRD, SEM, VSM and UV-vis DRS analysis methods. The influence of various parameters was investigated, such as dye type, dye concentration, H2O2 dosage, catalysts dosage and pH of MO solution during heterogeneous photo-Fenton processes. Under visible light irradiation, the degradation rate of MO, MB and CR could reach 99.96%, 98.47% and 99.97% in 40 min, respectively. Six cycle experiments confirmed that the α-FeOOH@MGO possessed a satisfied stability and recycling ability. In addition, the photocatalytic reaction mechanism was also revealed by the Mott-Schottky plot, band structure and trapping experiments of active species.

Preparation of chitosan-like magnetic composite microspheres and their adsorption properties for Cu (II)

The novel magnetic composite microspheres (Fe3O4/HAD-C) coated with Fe3O4 were fabricated by inverse suspension cross-linking method, where glutaraldehyde was used as a crosslinking agent. Magnetic Fe3O4 particles and Hexamethylene Diamine Cellulose was prepared respectively by the chemical coprecipitation method and grafting amino group onto microcrystalline Cellulose. The scanning electron microscope, laser particle size analyzer, X-ray diffractometer, and thermogravimetric analyzer were used to characterize the magnetic Fe3O4/HAD-C composite microspheres. The findings demonstrate that the Fe3O4/HAD-C composite microspheres were spherical and well dispersed with the size range between 0.3 μm and 1.2 μm, and possessed super paramagnetic property with 39.72 emu·g−1. The mass of Fe3O4 in the composite is about 37.11 %. By using an adsorption study, the removal of Cu (II) from heavy metal wastewater by Fe3O4/HAD-C was examined. The findings showed that the composite microsphere made of Fe3O4/HAD-C effectively absorbed Cu (II). The entire adsorption procedure follows the Langmuir isothermal adsorption model and pseudo-second order kinetics. Fe3O4/HAD-C also had high reusability and stability. Even after 5 cycles of adsorption and desorption, Fe3O4/HAD-C still achieve 32.45 mg g−1. Environmentally friendly and effective, the unique magnetic chitosan-like composite microspheres (Fe3O4/HAD-C) developed in this study.

Fabrication of novel starch-based composite hydrogel microspheres combining Diels-Alder reaction with spray drying for MB adsorption

Herein, magnetic starch-based composite hydrogel microspheres (SCHMs) were produced via a Diels-Alder reaction during spray drying. The adsorption behavior of SCHMs for methylene blue (MB) was investigated systematically. The adsorption process could be described by Langmuir isothermal model and pseudo-first-order kinetic model with R2 > 0.95 and R2 > 0.98, respectively, resulting from its dominating physical adsorption. The thermodynamic studies showed the adsorption was spontaneous and the nature of adsorption was endothermic due to that the free energy ∆G was a negative value and the enthalpy ∆H was a positive value. The absorbent had good reusability with 90.5% of removal efficiency after 5 cycles. In addition, the effects of concentration, pH and temperature on the adsorption of MB by SCHMs were optimized using the Box-Behnken Design and response surface methodology. The order of three factors affecting the adsorption capacity of SCHMS is initial pH > initial concentration > temperature. Due to their safe, non-toxic and easily recycled advantages, SCHMs have the potential to be applied to water treatment in the future.

Magnetic solid phase extraction based on dodecyl functionalization of magnetic ferrite microspheres for determination of phthalate esters in environmental water

A fast, simple, and efficient sample pretreatment technique based on magnetic dodecyl functionalization of magnetic ferrite microspheres has been developed for the extraction and pre-concentration of phthalate esters from environmental water prior to high-performance liquid chromatography analysis. The magnetic composite microspheres were prepared using Fe3O4 microspheres as magnetic core and silica as a shell with the surface-modified with C12 material. The structure of the prepared microspheres was characterized by Fourier transform infrared spectrometry, scanning electron microscopy, and vibrating sample magnetometry. Three kinds of phthalate esters were selected as model compounds to optimize the main parameters that affect extraction efficiencies, such as adsorbent dosage, sample volume, salt addition, extraction time, pH of sample solution, desorption time, eluent type, and volume. Under the optimal conditions, limits of detection (LODs) of 0.025–0.107 ng mL−1 and limits of quantification (LOQs) of 0.083–0.357 ng mL−1 were achieved. The developed method was applied for the detection of the three PAEs in a spiked sample of river water, and satisfactory recoveries in the range of 76.3–98.9% were obtained with good repeatability (RSD < 4.7%). The entire analysis process can be completed in about 30 min.

Wrinkled Fe3O4@C magnetic composite microspheres: Regulation of magnetic content and their microwave absorbing performance

In this work, we develop a novel synthetic strategy for wrinkled magnetic composite microspheres (Fe3O4@C). Firstly, hydrophobic oleic acid modified Fe3O4 (OA-Fe3O4) nanoparticles acted as the magnetic component are prepared by synchronous modification coprecipitation method. The macromolecular emulsifier with initiating activity is obtained by means of soap-free emulsion polymerization under the presence of 1,1-diphenylethylene (DPE). Then, interfacial polymerization is employed to synthesis Fe3O4@polymethylglycidyl ester/divinylbenzene composite microspheres (Fe3O4@PGMA/DVB). Fe3O4@C composite microspheres are obtained by vacuum carbonization of the microspheres. The effect of magnetic content on the microwave absorbing properties of Fe3O4@C composite microspheres is explored. The results show that Fe3O4@C composite microspheres exhibit the excellent application performance at the Fe3O4 content of 0.15 g. The reflection loss can reach −53.7 dB at only thickness of 1.7 mm. The Maximum effective absorption bandwidth is up to 5.26 GHz with a thickness of 1.9 mm. The microwave attenuation mechanism of Fe3O4@C composite microspheres is revealed. The excellent absorbing performance is attributed to the enhanced interfacial polarization ability, the surface wrinkled structure and the good synergy between dielectric and magnetic losses. This work provides an effective strategy for the design and preparation of new magnetic composite materials.

Characteristics and mechanism of Cu(II) adsorption on prepared calcium alginate/carboxymethyl cellulose@MnFe2O4

A magnetic composite microsphere, calcium alginate (CA)/carboxymethyl cellulose (CMC)@MnFe2O4, was prepared using CA and CMC encapsulated MnFe2O4 through blending and cross-linking for the removal of Cu(II) from aqueous solution. The CA/CMC@MnFe2O4 was characterized in detail by Fourier transform infrared spectroscopy, X-ray diffraction, scanning electron microscopy, and X-ray phosphorescence spectroscopy. In addition, various adsorption conditions including the initial pH of Cu(II) solution, equilibrium contact time, and initial Cu(II) concentration were tested. The adsorption data fit better to the Langmuir isotherm and follow the pseudo-second-order model, suggesting that it is a monolayer adsorption process with chemisorption as the rate-limiting step. The maximum adsorption capacity of the CA/CMC@MnFe2O4 was 77.22 mg g−1 at 25 ℃ and pH 5. Cu(II) removal mechanisms of CA/CMC@MnFe2O4 follow ion exchange as well as the formation of complexes as evidenced based on the microstructure analysis and adsorption data fitting.

Laccase immobilization on core-shell magnetic metal-organic framework microspheres for alkylphenol ethoxylate compound removal

An amino-functionalized magnetic core-shell structure metal-organic framework (MOF), Fe3O4-NH2@MIL-100 (Fe), has been successfully constructed by a step-by-step method. The composite microspheres exhibited excellent magnetic characteristics, large surface area, and pore size, which were employed for the Trametes versicolor laccase immobilization. The immobilized laccase exhibited high activity recovery (72.05%) and significantly improved stability. The reactive activity remained 75% of its initial activity after storage for 4 weeks. Additionally, when the ambient reached 80 °C, the good stability enabled the immobilization laccase to keep 33% residual activity even after 6 h storage. Application of the immobilized laccase for environmental pollutant alkylphenol polyethoxylate (APEO) removal was also investigated. The results showed the immobilized laccase can remove 100% octylphenol polyethoxylate (OPEO) and 98.16% nonylphenol polyethoxylate (NPEO) in 200 min, and can still achieve 63.42% and 46.17% removal efficiency for OPEO and NPEO after reusing four cycles, respectively. The novel MOF based core-shell magnetic composite microspheres introduced by this study showed promising applications as laccase immobilization support, and both the immobilized laccase and its support had great potential in wastewater treatment.

The synthesis and water-swelling performances of magnetic composite microspheres with multi-shell structures via a combination method

Magnetic composite polymeric microspheres have several technical advantages in improving oil recovery applications. Swelling and stability are key properties that are a direct result of water shutoff efficacy. However, the important aspect of swelling and stability is the materials of the microspheres. In this paper, multiple–shell structures of magnetic hybrid composite spherical particles with different materials which were Fe3O4@SiO2@PAM, Fe3O4@TiO2@PAM, Fe3O4@SiO2@PAM-MBAAm were synthesized via a combination method and theirs physical properties including morphology, particle size distribution, and water swelling property were thoroughly examined. Meanwhile, the plugging performances were studied. The main goal of this paper was to investigate effect of materials of constituents on swelling properties of microspheres. The results demonstrate that both inorganic and organic constituents can affect the swelling properties of microspheres. Moreover, plugging properties of microspheres with different components are different at different salt concentrations, temperatures and pH values. Meanwhile, the results also open up possibilities for studying on the system of heat-resistant, salt-resistant, and pH-resistant oil displacement agent.

A Mild Method for Preparation of Highly Selective Magnetic Biochar Microspheres.

We report the use of biochar and Fe3O4 nanoparticles as co-stabilizers for oil-in-water (o/w) Pickering emulsion. The emulsion is subsequently used to prepare magnetic tetracycline-imprinted biochar composite microspheres (MMIPMs) with good uniformity and high selectivity. The MMIPMs were characterized by scanning electron microscopy (SEM), Brunner-Emmet-Teller (BET) measurements, Fourier transform infrared spectrometry (FT-IR), X-ray diffraction (XRD), vibrating sample magnetometer (VSM) and thermogravimetry analysis (TGA). The adsorption properties of tetracycline to the MMIPMs were investigated using different adsorption experiments including adsorption kinetic experiment, equilibrium binding experiment, selectivity evaluation and competitive adsorption tests. The theoretical maximum adsorption capacity of the MMIPMs (15.45 mg g−1) was greater than that of the raw biochar (2.10 mg g−1) and non-imprinted biochar composite microspheres (3.39 mg g−1) for tetracycline. Further, the MMIPMs were used as adsorbent for magnetic solid phase extraction (SPE) for the extraction of tetracycline present in drinking water, milk, fish and chicken samples. Under optimal conditions, the results showed good recovery yield ranging from 88.41% to 106.29% with a relative standard deviation (RSD) ranging from 0.35% to 6.83%, respectively.