Facile synthesis of porous Fe3O4@C core/shell nanorod/graphene for improving microwave absorption properties

Porous Fe₃O₄@C core/shell nanorods decorated with reduced graphene oxide (RGO) were fabricated through a facile one-pot method. The microwave absorption properties of the samples can be adjusted by the weight ratio of RGO. The addition of RGO not only effectively reduces the agglomeration of Fe₃O₄@C, but also has a great effect on impedance matching and dielectric loss, resulting in enhanced microwave absorption abilities. The thickness corresponding to optimum reflection loss (R_L) decreases as the weight ratio of RGO increases. For the Fe₃O₄@C/RGO composite, a maximum R_L value of −48.6 dB can be obtained at 13.9 GHz with a thickness of 3.0 mm, and the absorption bandwidth with R_L below −10 dB is 7.1 GHz from 10.9 GHz to 18 GHz. These results demonstrate a facile method to prepare a highly efficient microwave absorption material with special microstructure.

Porous Fe₃O₄@C core/shell nanorods decorated with reduced graphene oxide were synthesized by a facile one-pot method, and exhibit high microwave absorption performance: maximum reflection loss reaches −48.6 dB.     

Antibacterial and plant growth-promoting properties of novel Fe3O4/Cu/CuO magnetic nanoparticles

In this work, an Fe₃O₄/Cu/CuO (FC) antibacterial nano-agent was synthesized in a “one-pot” approach using copper sulfate and ferric chloride as raw materials, and it was studied using TEM, XRD, XPS, UV-vis, and VSM methods. The antibacterial activity and mechanism of FC were studied, using a commercially available Bordeaux mixture as a control. The effects of an FC on mung bean development and its toxicity to human mammary epithelial cells were also investigated. The results revealed that FC could break the cell walls of E. coli and S. aureus, quadrupling the antibacterial activity of the Bordeaux combination. Furthermore, it was shown that FC might improve the germination, root development, and chlorophyll content of mung bean seeds while being 1/8 as hazardous to human mammary epithelial cells as the Bordeaux combination. The as-prepared FC can replace the Bordeaux combination in the management of agroforestry pathogens.

In this work, an Fe₃O₄/Cu/CuO (FC) antibacterial nano-agent was synthesized in a “one-pot” approach using copper sulfate and ferric chloride as raw materials, and it was studied using TEM, XRD, XPS, UV-vis, and VSM methods.     

Facile fabrication of water-dispersible nanocomposites based on hexa-peri-hexabenzocoronene and Fe3O4 for dual mode imaging (fluorescent/MR) and drug delivery

The facile fabrication of multifunctional nanocomposites (Fe₃O₄/HBC@F127) consisting of superparamagnetic Fe₃O₄ nanoparticles and fluorescent organic hexa-peri-hexabenzocoronene (HBC) molecules incorporated in block copolymer diacylphospholipid–polyethyleneglycol F127 have been demonstrated for dual mode imaging (fluorescent/MR) and drug delivery. The obtained nanocomposites were water-dispersible, stable and biocompatible, as confirmed by dynamic light scattering (DLS) and 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. Relativity measurements showed a T₂ relaxivity (r₂) of 214.61 mM⁻¹ s⁻¹, which may be used as T₂-weighted MR imaging agents. In vitro imaging studies indicated that the nanocomposites had good MR and fluorescence imaging effects with low cytotoxicity. Besides, the developed nanocomposites could also be applied as drug delivery vehicles. Doxorubicin (DOX) loaded Fe₃O₄/HBC@F127 nanocomposites significantly inhibited the growth of human hepatoma cells (HepG2). These findings suggested that the facile synthesized multifunctional nanocomposites may be used as a platform for dual mode imaging (both MR and fluorescence) and drug delivery.

Water-dispersible, stable and biocompatible dandelion-like Fe₃O₄/HBC@F127 nanocomposites were facilely developed for dual mode imaging (fluorescent/MR) and drug delivery.     

Visible-light photocatalytic performance,recovery and degradation mechanism of ternary magnetic Fe3O4/BiOBr/BiOI composite

The ternary magnetic Fe₃O₄/BiOBr/BiOI (x : 3 : 1) photocatalysts were successfully synthesized by a facile solvothermal method. The samples were characterized by XRD, SEM, EDS, ICP-AES, XPS, UV-vis DRS, PL and VSM. Nitrogen-containing dye RhB was used as a degradation substrate to evaluate the photocatalytic degradation activities of the samples. The photocatalytic performance of Fe₃O₄/BiOBr/BiOI (0.4 : 3 : 1) is superior to other Fe₃O₄/BiOBr/BiOI (x : 3 : 1). Compared with binary magnetic Fe₃O₄/BiOBr (0.5 : 1) prepared in our previous work, the Fe₃O₄/BiOBr/BiOI (0.4 : 3 : 1) has obvious advantages in photocatalytic activity and adsorption capacity. And the specific surface area (48.30 m² g⁻¹) is much larger than that of the previous report (Fe₃O₄/BiOBr/BiOI (0.5 : 2 : 2)) synthesized by a co-precipitation method. Besides, after 25 s of magnetic field, Fe₃O₄/BiOBr/BiOI (0.4 : 3 : 1) can be rapidly separated from water. After eight recycling cycles, the magnetic properties, photocatalytic activity, crystallization and morphology of the Fe₃O₄/BiOBr/BiOI (0.4 : 3 : 1) catalyst remain good. The possible photocatalytic degradation mechanism of RhB under Fe₃O₄/BiOBr/BiOI (0.4 : 3 : 1) photocatalyst was also proposed. The results indicate that the ternary magnetic Fe₃O₄/BiOBr/BiOI (0.4 : 3 : 1) composite with high photocatalytic degradation efficiency, good magnetic separation performance and excellent recyclability and stability has potential application prospect in wastewater.

The ternary magnetic Fe₃O₄/BiOBr/BiOI (x : 3 : 1) photocatalysts were successfully synthesized by a facile solvothermal method.     

Synthesis of Fe3O4@PVBC–TMT nanoparticles for the efficient removal of heavy metals ions

Core–shell magnetic Fe₃O₄@PVBC–TMT (Fe₃O₄@polyvinylbenzyl chloride–trithiocyanuric acid) nanoparticles containing trithiocyanuric acid groups were fabricated and employed for the fast removal of heavy metals from an aquatic environment. The morphology, structure and properties of Fe₃O₄@PVBC–TMT nanoparticles were characterized by a series of modern analytical tools. The adsorption behavior of the Fe₃O₄@PVBC–TMT nanoparticles for heavy metals ions in aqueous solutions was investigated by batch experiments. The maximum removal capacities of the Fe₃O₄@PVBC–TMT nanoparticles toward Mn²⁺, Ni²⁺, Cu²⁺, Cd²⁺ and Pb²⁺ ions were 127.4, 146.6, 180.5, 311.5, and 528.8 mg g⁻¹, respectively. Importantly, it is found that Pb²⁺ ions can be completely and quickly removed by the Fe₃O₄@PVBC–TMT nanoparticles. The equilibrium was established within 6 min, and the removal efficiencies were found to be 99.9%, 99.8% and 99.5% for Pb²⁺ ions at the initial concentrations of 100 mg L⁻¹, 200 mg L⁻¹ and 300 mg L⁻¹, respectively. It is hoped that the core–shell magnetic Fe₃O₄@PVBC–TMT nanoparticles may find application in wastewater treatment.

Core–shell Fe₃O₄@PVBC–TMT nanoparticles were fabricated and served as a valid magnetic adsorbent for the removal of heavy metals ions.     

Fe3O4磁性微粒的制备及表征

背景:磁性微粒作为一种磁性载体在固定化酶、免疫检测、靶向载药治疗及细胞分离等生物医学领域得到了广泛的应用.目的:制备分散稳定性好,相对磁性强的纳米级Fe3O4微粒.方法:以氯化亚铁、氯化铁、氢氧化钠为主要原料,采用化学共沉淀法合成Fe3O4磁性粒子.结果与结论:用正交设计法优化了Fe3O4微粒的合成工艺条件,得到制备Fe3O4粒子的最佳实验条件为Fe2+/Fe3+的物质的量之比为2∶1、共沉淀时的pH值为11、熟化温度为90 ℃、表面活性剂聚乙二醇的用量为40 mL,此时制得的Fe3O4粒子粒径最小,为78 nm,Fe3O4溶液的分散稳定性最好,相对磁性最强.从Fe3O4的扫描电镜图可以看出,Fe3O4微粒晶体颗粒为纳米级.     

A multifunctional composite Fe3O4/MOF/l-cysteine for removal,magnetic solid phase extraction and fluorescence sensing of Cd(ii)

Fe₃O₄/MOF (metal organic framework)/l-cysteine was synthesized and applied for the removal of Cd(ii) from wastewater. The adsorption kinetics and isotherms were investigated, and the results indicated that the adsorption obeyed the pseudo-second-order kinetic model and Langmuir isotherm. The maximum adsorption capacity was calculated to be 248.24 mg g⁻¹. Fe₃O₄/MOF/l-cysteine was further applied to determine trace amounts of Cd(ii) in real water samples using ICP-AES (inductively coupled plasma-atomic emission spectroscopy) based on magnetic solid-phase extraction (MSPE). The determination limit was 10.6 ng mL⁻¹. Additionally, Fe₃O₄/MOF/l-cysteine can also be used as a fluorescent sensor for “turn-off” detection of Cd(ii), and the detection limit was 0.94 ng mL⁻¹.

Fe₃O₄/MOF (metal organic framework)/l-cysteine was synthesized and applied for the removal of Cd(ii) from wastewater.     

Facile route to synthesize Fe3O4@acacia–SO3H nanocomposite as a heterogeneous magnetic system for catalytic applications

In this work, a novel catalytic system for facilitating the organic multicomponent synthesis of 9-phenyl hexahydroacridine pharmaceutical derivatives is reported. Concisely, this catalyst was constructed from acacia gum (gum arabic) as a natural polymeric base, iron oxide magnetic nanoparticles (Fe₃O₄ NPs), and sulfone functional groups on the surface as the main active catalytic sites. Herein, a convenient preparation method for this nanoscale composite is introduced. Then, essential characterization methods such as various spectroscopic analyses and electron microscopy (EM) were performed on the fabricated nano-powder. The thermal stability and magnetic properties were also precisely monitored via thermogravimetric analysis (TGA) and vibrating-sample magnetometry (VSM) methods. Then, the performance of the presented catalytic system (Fe₃O₄@acacia–SO₃H) was further investigated in the referred organic reaction by using various derivatives of the components involved in the reaction. Optimization, mechanistic studies, and reusability screening were carried out for this efficient catalyst as well. Overall, remarkable reaction yields (94%) were obtained for the various produced derivatives of 9-phenyl hexahydroacridine in the indicated optimal conditions.

We designed and fabricated a novel catalytic system with high heterogeneity and magnetic features to facilitate the MCR synthetic reactions of 9-phenyl hexahydroacridine pharmaceutical derivatives.     

Zn2+ removal from the aqueous environment using a polydopamine/hydroxyapatite/Fe3O4 magnetic composite under ultrasonic waves

In this study, an easily magnetically recoverable polydopamine (PDA)-modified hydroxyapatite (HAp)/Fe₃O₄ magnetic composite (HAp/Fe₃O₄/PDA) was suitably synthesized to exploit its adsorption capacity to remove Zn²⁺ from aqueous solution, and its structural properties were thoroughly examined using different analytical techniques. The effect of multiple parameters like pH, ultrasonic power, ultrasonic time, adsorbent dose, and initial Zn²⁺ concentration on the adsorption efficiency was assessed using RSM-CCD. According to the acquired results, by increasing the adsorbent quantity, ultrasonic power, ultrasonic time, and pH, the Zn²⁺ adsorption efficiency increased and the interaction between the variables of ultrasonic power/Zn²⁺ concentration, pH/Zn²⁺ concentration, pH/absorbent dose, and ultrasonic time/adsorbent dose has a vital role in the Zn²⁺ adsorption. The uptake process of Zn²⁺ onto PDA/HAp/Fe₃O₄ followed Freundlich and pseudo-second order kinetic models. The maximum capacity of Zn²⁺ adsorption (q_m) obtained by PDA/HAp/Fe₃O₄, HAp/Fe₃O₄, and HAp was determined as 46.37 mg g⁻¹, 40.07 mg g⁻¹, and 37.57 mg g⁻¹, respectively. Due to its good performance and recoverability (ten times), the HAp/Fe₃O₄/PDA magnetic composite can be proposed as a good candidate to eliminate Zn²⁺ ions from a water solution.

A magnetically recoverable polydopamine (PDA)-modified hydroxyapatite (HAp)/Fe₃O₄ magnetic composite (HAp/Fe₃O₄/PDA) was synthesized to exploit its adsorption capacity to remove Zn²⁺ from aqueous solution and the structural properties were examined.     

Ultrasound-assisted coagulation for Microcystis aeruginosa removal using Fe3O4-loaded carbon nanotubes

Harmful cyanobacterial blooms are increasing environmental issues and require novel removal technology since the required doses of algaecides may cause further environmental pollution or treatment facility damage. Herein, we firstly introduce the combination of ultrasound and Fe₃O₄/CNTs as an alternative strategy to enhance coagulation for the removal of Microcystis aeruginosa cells in water. It remarkably enhanced cyanobacterial cell removal and microcystins control, compared with sonication alone (40 kHz ultrasonic bath, 4.2 mJ mL⁻¹). 94.4% cyanobacterial cells were removed using 20 second sonication with 20 mg L⁻¹ Fe₃O₄/CNTs, Al₂(SO₄)₃ coagulation (20 μM). Both sonication time and catalyst dose significantly influenced the cyanobacterial removal. Ultrasound with Fe₃O₄/CNTs only induced a slight increase of cell permeability, which may contribute to the effective control of DOC and microcystins'' release in water. The enhanced settlement of the cyanobacterial cells may result from the moderate oxidation on the cell surface. This study suggested a novel ultrasound-Fe₃O₄/CNT process to promote cyanobacteria removal with efficient DOC and microcystin release control, which is a green and safe technology for drinking water treatment.

The combination of sonication and Fe₃O₄/CNTs were applied on Microcystis aeruginosa removal for the first time.     

Adsorption mechanism of polyethyleneimine modified magnetic core–shell Fe3O4@SiO2 nanoparticles for anionic dye removal

In this paper, polyethyleneimine modified magnetic core–shell Fe₃O₄@SiO₂ nanoparticles (Fe₃O₄@SiO₂/PEI) were innovatively synthesized and investigated using various techniques such as TEM, TGA, FT-IR, XRD, VSM and XPS. The adsorption performance based on the removal of the anionic dyes Methyl orange and Congo red from aqueous solution was studied systematically. The results showed that the adsorption rate of anionic dyes MO and CR increased rapidly then decreased gradually as the pH increased, the adsorption capacity of Fe₃O₄@SiO₂/PEI for MO was better than that for CR, and the maximum adsorption capacity for MO and CR was 231.0 mg g⁻¹ at pH 4 and 134.6 mg g⁻¹ at pH 6, respectively. The equilibrium adsorption capacities for MO and CR increased rapidly in the initial 40 min, and reached equilibrium in approximately 180 min, while the adsorption capacity for MB was relative low even negligible, demonstrating the strong adsorptive affinity of Fe₃O₄@SiO₂/PEI toward anionic compounds. Both of the adsorption processes followed the pseudo-second-order kinetics model and the Freundlich isotherm model. The mechanism of adsorption was mainly related to electrostatic attraction and the number of active sites occupied by anionic dyes. This study provides valuable guidance and is an effective method for the removal of anionic dyes from aquatic environments.

In this paper, polyethyleneimine modified magnetic core–shell Fe₃O₄@SiO₂ nanoparticles (Fe₃O₄@SiO₂/PEI) were innovatively synthesized and investigated using various techniques such as TEM, TGA, FT-IR, XRD, VSM and XPS.     

Facile fabrication of bimetallic Fe–Mg MOF for the synthesis of xanthenes and removal of heavy metal ions

This work reported the preparation of Mg-MOF, Fe-MOF and Fe–Mg MOF by a solvothermal technique and their characterization with FT-IR, XRD, SEM, EDS, TEM and S_BET analyses. The nanoparticle diameter ranged from 3.1 to 10.9 nm. The acidity of the MOFs was measured by nonaqueous potentiometric titration of n-butylamine. It was observed that the formation of a bimetallic MOF sharply increases the surface acidity and the catalytic activity. The catalytic results of the Fe–Mg MOF catalyzing the synthesis of 14-aryl-14-H-dibenzo[a,j]xanthenes in comparison with those of parent MOFs showed a higher yield of the desired product in a lower time and among various Fe : Mg, the (0.6 : 1) Fe–Mg MOF showed the highest catalytic activity and acidity. Even after the 4^th run, the Fe–Mg MOF catalyst still maintained nearly the initial catalytic activity. The adsorption performance of Mg-MOF, Fe-MOF and Fe–Mg MOF was evaluated by batch experiments. The effect of contact time, the solution pH, the adsorbent dose and the initial concentration of the heavy metal ions was discussed. It was found that the capacity of the bimetallic Fe–Mg MOF for Pb(ii), Cu(ii) and Cd(ii) adsorption was higher than that of the Mg-MOF and Fe-MOF, the kinetic data followed the pseudo-second-order kinetic model and the isothermal data obeyed the Langmuir isotherm model. The mechanism of the removal of the heavy metal ions was discussed.

This work reported the preparation of Mg-MOF, Fe-MOF and Fe–Mg MOF by a solvothermal technique and their characterization with FT-IR, XRD, SEM, EDS, TEM and S_BET analyses.     

Promoted adsorptive removal of chromium(vi) ions from water by a green-synthesized hybrid magnetic nanocomposite (NFe3O4Starch-Glu-NFe3O4ED)

A novel magnetic starch-crosslinked-magnetic ethylenediamine nanocomposite, NFe₃O₄Starch-Glu-NFe₃O₄ED, was synthesized via microwave irradiation. The characteristics of the assembled NFe₃O₄Starch-Glu-NFe₃O₄ED nanocomposite were evaluated via XRD, FT-IR, TGA, BET, SEM and HR-TEM analyses. Its particle size was confirmed to be in the range 11.25–17.16 nm. The effectiveness of the designed nanocomposite for the removal of Cr(vi) ions was explored using the batch adsorption technique. Equilibrium results proved that the adsorptive removal of the target metal ions from aqueous solution was highly dependent on the optimized experimental parameters. The maximum adsorptive removal percentage values (%R) of Cr(vi) ions on NFe₃O₄Starch-Glu-NFe₃O₄ED obtained at pH 2.0 were 85.27%, 91.90%, and 96.47% using 10.0, 25.0, and 50.0 mg L⁻¹ Cr(vi), respectively, for an equilibrium time of 30 min. The adsorption process was found to be strongly influenced by the presence of interfering salts including NaCl, CaCl₂, KCl, MgCl₂, and NH₄Cl. Kinetic studies were performed and it was found that the pseudo-second and Elovich models well fitted the experimental data with the possible suggested ion-pair interaction mechanism. Different isotherm models were employed to assess the adsorption equilibrium, which was revealed by fitting Langmuir, Temkin and Freundlich models. The maximum uptake capacity based on the Langmuir model was 210.741 mg g⁻¹. The effect of temperature and thermodynamics confirmed that adsorption was spontaneous, feasible, and endothermic in nature. Finally, the validity and applicability of using the NFe₃O₄Starch-Glu-NFe₃O₄ED nanocomposite to remove Cr(vi) ions from real water matrices were confirmed in the range of 91.2–94.7 ± 2.2–3.7%.

A novel magnetic starch-crosslinked-magnetic ethylenediamine nanocomposite, NFe₃O₄Starch-Glu-NFe₃O₄ED, was synthesized via microwave irradiation for the removal of Cr(vi) ions from aquous solution using the batch adsorption technique.     

Correction: Facile preparation of novel quaternary g-C3N4/Fe3O4/AgI/Bi2S3 nanocomposites: magnetically separable visible-light-driven photocatalysts with significantly enhanced activity

Correction for ‘Facile preparation of novel quaternary g-C₃N₄/Fe₃O₄/AgI/Bi₂S₃ nanocomposites: magnetically separable visible-light-driven photocatalysts with significantly enhanced activity’ by Anise Akhundi et al., RSC Adv., 2016, 6, 106572–106583. DOI: 10.1039/C6RA12414C.

The authors regret that incorrect images were used in Fig. 2i (page 106575) and Fig. 3b (page 106576). The correct images are shown below.Fig. 2i. EDX mapping of the g-C₃N₄/Fe₃O₄/AgI/Bi₂S₃ (30%) nanocomposite.Fig. 3b TEM image of the g-C₃N₄/Fe₃O₄/AgI/Bi₂S₃ (30%) nanocomposite.The Royal Society of Chemistry apologises for these errors and any consequent inconvenience to authors and readers.     

Novel magnetic g-C3N4/α-Fe2O3/Fe3O4 composite for the very effective visible-light-Fenton degradation of Orange II

A novel magnetic heterogeneous g-C₃N₄/α-Fe₂O₃/Fe₃O₄ catalyst was successfully synthesized through a simple hydrothermal method. The structure, morphology, and optical properties of the catalyst were characterized. The photocatalytic activity of the heterogeneous g-C₃N₄/α-Fe₂O₃/Fe₃O₄ catalyst for the photo-Fenton degradation of Orange II in the presence of H₂O₂ irradiated with visible light (λ > 420 nm) at neutral pH was evaluated. The g-C₃N₄/α-Fe₂O₃/Fe₃O₄ photocatalyst was found to be an excellent catalyst for the degradation of Orange II and offers great advantages over the traditional Fenton system (Fe(ii/iii)/H₂O₂). The results indicated that successfully combining monodispersed Fe₃O₄ nanoparticles and g-C₃N₄/α-Fe₂O₃ enhanced light harvesting, retarded photogenerated electron–hole recombination, and significantly enhanced the photocatalytic activity of the system. The g-C₃N₄/α-Fe₂O₃/Fe₃O₄ (30%) sample gave the highest degradation rate constant, 0.091 min⁻¹, which was almost 4.01 times higher than the degradation rate constant for α-Fe₂O₃ and 2.65 times higher than the degradation rate constant for g-C₃N₄/α-Fe₂O₃ under the same conditions. A reasonable mechanism for catalysis by the g-C₃N₄/α-Fe₂O₃/Fe₃O₄ composite was developed. The g-C₃N₄/α-Fe₂O₃/Fe₃O₄ composite was found to be stable and recyclable, meaning it has great potential for use as a photo-Fenton catalyst for effectively degrading organic pollutants in wastewater.

A novel magnetic heterogeneous g-C₃N₄/α-Fe₂O₃/Fe₃O₄ catalyst was firstly synthesized and exhibited very effective visible-light-Fenton degradation of Orange II at neutral pH.     

Facile synthesis of silver nanocatalyst decorated Fe3O4@PDA core–shell nanoparticles with enhanced catalytic properties and selectivity

In this work, we have successfully prepared core–shell nanoparticles (Fe₃O₄@PDA) wrapped with Ag using a simple and green synthesis method. Without an external reducing agent, silver nanoparticles (Ag NPs) with good dispersibility were directly reduced and deposited on a polydopamine (PDA) layer. Fe₃O₄@PDA@Ag showed excellent catalytic activity and recyclability for 4-nitrophenol, and also exhibited good catalytic selectivity for organic dyes (MO and MB). This simple and green synthesis method will provide a platform for other catalytic applications.

In this work, we have successfully prepared core–shell nanoparticles (Fe₃O₄@PDA) wrapped with Ag using a simple and green synthesis method.     

Magnetically retrievable Ce-doped Fe3O4 nanoparticles as scaffolds for the removal of azo dyes

Considering the significant impact of magnetically retrievable nanostructures, herein, Fe₃O₄ and Ce-doped Fe₃O₄ nanoparticles were employed as scaffolds for the removal of the Reactive Black 5 (RB5) azo dye. We synthesized the Ce-doped Fe₃O₄ nanoparticles via hydrothermal treatment at 120 °C for 10 h with varying cerium concentrations (1.5–3.5%) and characterized them using basic techniques such as FTIR and UV-visible spectroscopy, and XRD analysis. The retention of their magnetic behaviors even after cerium amalgamation was demonstrated and confirmed by the VSM results. FESEM and EDX were used for the morphological and purity analysis of the synthesized nanoabsorbents. XPS was carried out to determine the electronic configuration of the synthesized samples. The porosity of the magnetic nanoparticles was investigated by BET analysis, and subsequently, the most porous sample was further used in the adsorption studies for the cleanup of RB5 from wastewater. The dye adsorption studies were probed via UV-visible spectroscopy, which indicated the removal efficiency of 87%. The prepared Ce-doped Fe₃O₄ nanoabsorbent showed the high adsorption capacity of 84.58 mg g⁻¹ towards RB5 in 40 min. This is attributed to the electrostatic interactions between the nanoabsorbent and the dye molecules and high porosity of the prepared sample. The adsorption mechanism was also analyzed. The kinetic data well-fitted the pseudo-first-order model, and the adsorption capability at different equilibrium concentrations of the dye solution indicated monolayer formation and chemisorption phenomena. Furthermore, the magnetic absorbent could be rapidly separated from the wastewater using an external magnetic field after adsorption.

Considering the significant impact of magnetically retrievable nanostructures, herein, Ce-doped Fe₃O₄ nanoparticles were employed as scaffolds for the removal of the Reactive Black 5 (RB5), an azo dye.     

A designable aminophenylboronic acid functionalized magnetic Fe3O4/ZIF-8/APBA for specific recognition of glycoproteins and glycopeptides

We fabricated a novel aminophenylboronic acid functionalized magnetic Fe₃O₄/zeolitic imidazolate framework-8/APBA (denoted as Fe₃O₄/ZIF-8/APBA). First, Fe₃O₄ was coated by zeolitic imidazolate framework-8 (denoted as Fe₃O₄/ZIF-8) using the hydrothermal method. Next, the phenylboronic acid functionalized triethoxysilane reagent was synthesized by 3-aminophenylboronic acid and 3-isocyanatopropyltriethoxysilane, which was modified on the surface of the Fe₃O₄/ZIF-8 nanocomposite through the sol–gel technique and electrostatic interaction as well as π–π stacking interaction. The synthetic Fe₃O₄/ZIF-8/APBA exhibited high adsorption capacity and good specificity toward glycoproteins. Moreover, the Fe₃O₄/ZIF-8/APBA possessed high saturation magnetization (51.41 emu g⁻¹) and achieved better separation in the presence of an external magnetic field. Above all, the as-designed Fe₃O₄/ZIF-8/APBA was successfully used to capture glycoproteins and identify the horseradish peroxidase (HRP) tryptic digest. This study provides a facile strategy to embellish the aminophenylboronic acid onto the nanocomposite substrate and develop a new material for the specific recognition and enrichment of glycoproteins and low-abundance glycopeptides in proteomics research.

We fabricated a novel aminophenylboronic acid functionalized magnetic Fe₃O₄/zeolitic imidazolate framework-8/APBA (denoted as Fe₃O₄/ZIF-8/APBA).     

Facile fabrication of composite cellulose fibrous materials for efficient and consecutive dyeing wastewater treatment

Fabricating dye adsorbents with efficient adsorption properties is of great significance in the treatment of printing and dyeing wastewater. Herein, composite materials of polydopamine decorated cellulose fibrous nonwovens (PDA@CF NWs) were fabricated by constructing a PDA functional layer on the surface of cellulose fibers via in situ polymerization. In addition, a three-dimensional adsorbent of 3D PDA@CF NWs with good hydrophilicity, structural stability, and compression resistance could be obtained using a facilely laminating and traditional loop bonding reinforcing technique. Attributed to the efficient and uniform loading of an active PDA functional layer, the resulting PDA@CF NWs exhibited a relatively large adsorption capacity of around 91 mg g⁻¹ towards the template dye of methylene blue within a fast equilibrium time of 2 h, which was superior to most of the fibrous adsorbents. In addition, the treatment column of 3D PDA@CF NWs exhibited a breakthrough capacity of 40.9 mg g⁻¹, reaching nearly 50% of the static saturated dye-binding capacity. More importantly, the 3D PDA@CF NWs column could effectively and continuously separate the mixture of different dyes under gravity, highlighting an excellent practical performance. Thus, the PDA@CF NWs are expected to provide a promising candidate for environment-friendly, large-scale and efficient treatment of industrial printing and dyeing wastewater.

Composite materials of polydopamine decorated cellulose fibrous nonwovens were fabricated for efficient and consecutive dyeing wastewater treatment.