Medical nylon catheters (PA12) are essential instruments in interventional procedures, yet their inherent surface hydrophobicity and limited lubricity significantly restrict clinical performance. Although various hydrophilic coatings have been developed to address these issues, traditional physical coating methods often suffer from poor adhesion and delamination during use. To overcome these drawbacks, we developed a two-step chemical modification strategy involving epichlorohydrin (ECH) activation followed by covalent grafting of polyethyleneimine (PEI), aiming to construct a stable hydrophilic lubricating layer on PA12 catheter surfaces. XPS analysis revealed a marked change in the surface chemical composition, indicating the successful covalent grafting of PEI. The modified catheter exhibited a surface amino group density of 2.7229 µmol mm-2, approximately four times higher than that of the pristine PA12 catheter, indicating the successful grafting of PEI molecules onto the catheter surface. This modification markedly enhanced surface hydrophilicity, reducing the water contact angle from 103.54° to 62.01°, decreasing the friction coefficient by 36.9%, and nearly doubling water absorption. Moreover, the modified catheter displayed promising in vitro biocompatibility, as evidenced by non-cytotoxic extracts, a hemolysis rate of only 0.65%, and no detectable adverse effects on blood cell counts. Overall, this study presents a covalent grafting-based surface functionalization strategy for PA12 interventional catheters that improves both lubricity and surface hydrophilicity while retaining in vitro biosafety. These findings provide a basis for future investigations into the long-term stability and in vivo performance of the modified catheters.

Surface modification is essential to mitigate the thrombogenic and hydrophobic nature of medical catheters. However, conventional hydrophilic coatings often rely on chemical crosslinkers or photo-initiators, posing risks of cytotoxic residues. In this study, we report a zero-residue hydrophilic modification strategy utilizing an alkaline-induced physical crosslinking method. A dense Poly(vinyl alcohol) (PVA) hydrogel coating was established in situ on the catheter surface without exogenous chemical agents. The resulting coating exhibited superior lubricity, reducing the coefficient of friction by 86.67% (from 5.70 ± 0.11 N to 0.76 ± 0.03 N) and achieving a water contact angle of 58.2 ± 1.6°. Crucially, the coating demonstrated exceptional biocompatibility, with a hemolysis rate of only 1.093% and L929 cell viability exceeding 96.6%, far surpassing international safety standards. The physical crosslinking network also endowed the coating with robust mechanical stability (swelling ratio ~122%). This reliable, initiator-free approach offers a clinically safe solution for next-generation interventional medical devices.

In this study, monodisperse polystyrene microspheres with an average particle size of 3.81 mu m were first synthesized via dispersion polymerization combined with seed swelling polymerization. The resulting microspheres exhibited a uniform particle size and intact morphology. Subsequently, monodisperse magnetically permeable polystyrene microspheres were fabricated using a swelling-permeation method, which preserved the structural integrity of the microspheres while imparting high saturation magnetization, enabling rapid magnetic separation under an external magnetic field. The extractant P507 and the diluent 1, 2-dichloroethane were then loaded into the microspheres via an emulsion swelling process. The resulting functionalized microspheres featured uniform particle size, strong magnetic responsiveness, superparamagnetism, and favorable stability. Extraction experiments were conducted using a simulated red mud leachate solution containing 20 ppm Sc3+. Under conditions of pH 0.5 and an organic-to-aqueous phase ratio (O/A) ranging from 1:40 to 1:100, the extraction equilibrium was achieved within only 2-8 min, with a maximum extraction efficiency exceeding 95%. These results demonstrate excellent rapid mass transfer performance and efficient adsorption.

The presence of heavy metals in wastewater poses a substantial threat to both public health and the environment. However, the selective removal and separation of heavy metal ions at ultra-low concentrations from wastewater remains a considerable challenge. In this paper, we innovatively proposed a magnetic precipitation separation method to remove Cu (II) from wastewater using Fe3O4 nanoparticles and Na2S. In this process, the Cu (II) was reduced to CuS by Na2S, which then rapidly aggregated with Fe3O4 nanoparticles to form Fe3O4-CuS nano- clusters. SEM, DLS, XRD, VSM and XPS studies demonstrated that the removal of Cu (II) was related to the formation of Fe3O4-CuS nanoclusters. The results indicated that the removal efficiency of Cu (II) from wastewater could reach 99.75 % within 30 s. In contrast, the removal efficiencies of Co (II), Ni (II), and Zn (II) were 7.64 %, 6.14 %, and 8.41 %, respectively. In addition, the Fe3O4 nanoparticles were easily regenerated from Fe3O4-CuS nanoclusters using ultrasound, maintaining 98 % removal efficiency of Cu (II) after six consecutive cycles. These results suggested that this method held great potential for the removal of heavy metals from wastewater.

Recovering gold from electronic wastewater is of great significance in alleviating the shortage of metal resources and reducing environmental pollution, especially considering the increasing number of discarded electronic devices. However, the ultra-low concentration of gold and the competitive interference of various metals pose significant challenges. In this work, we used Fe3O4 nanoparticles and quaternary ammonium salt to recover gold from electronic wastewater. The method achieved a gold recovery efficiency of 98.2 % within just 3 min. The mechanism of gold recovery was investigated using techniques such as SEM, EDX, FT-IR, XPS, and XRD. The Au (III) ions were complexed with tetrabutylammonium nitrate to form the [N4444][AuCl4] complex, and this complex then aggregated with Fe3O4 nanoparticles to form nanoclusters, while Fe (II) ions on the surface of Fe3O4 nanoparticles reduced the Au (III) ions to Au (0). This study proposed a mechanism of complexation-aggregation-reduction-separation to recover gold. On application to a simulated electronic wastewater, the method exhibited excellent selectivity for Au (III), achieving a recovery efficiency of 99.1 %. The regeneration of Fe3O4 nanoparticles can be readily performed by ultrasound, retaining a 96.7 % recovery rate of Au (III) even after six consecutive cycles. This study proposed the combination of Fe3O4 nanoparticles and quaternary ammonium salt for gold recovery, which provided an environmentally friendly solution to address the increasing demand for precious metal resources in industry.

The recovery of low-concentration Au(III) from industrial wastewater holds significant economic and environmental value. Therefore, developing materials for the efficient extraction of low-concentration Au (III) is of great importance. In this study, we propose a novel microextraction scheme that combines the characteristics of microextraction with an extractant curing technique. Magnetic polystyrene microspheres serve as containers to encapsulate the extraction phase, which consists of the extractant (Aliquat 336) and the diluent (1,2-dichloroethane). Magnetic polystyrene microspheres with a diameter of 3.69 mu m were swollen using an emulsion containing Aliquat 336 and 1,2-dichloroethane, resulting in the formation of magnetic oil-based gel microspheres with a diameter of 10.14 mu m. These magnetic oil-based gel microspheres, which also contain Aliquat 336, are composed of 1,2-dichloroethane (81.73 wt%), Aliquat 336 (11.52 wt%), polystyrene (4.36 wt%), and iron tetroxide (1.69 wt%). At a low oil-to-water (O:A) ratio (ranging from 1:40 to 1:100), the microspheres achieved extraction equilibrium within 8 min. An eluent solution containing 0.1 mol center dot L- 1 hydrochloric acid and 0.05 mol center dot L- 1 thiourea was able to completely reverse the extraction of AuCl3 from the microspheres, facilitating their regeneration. The microspheres demonstrated stable and effective extraction capabilities over four cycles. In the presence of impurity ions (Ca2+, Fe3+, Cu2+, and Ni2+), the extraction rate of gold by the microspheres exceeded 95 %, while the extraction rate of the impurity ions remained below 10 %. This indicates the excellent selective extraction ability of the microspheres for Au(III).

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Magnetic metal–organic frameworks are attracting attention as excellent adsorbents due to abundant pore structures and easy separation. Two Fe3O4@MIL-100(Fe) (Fe3O4: ferroferric oxide, MIL: Materials of the Institut Lavoisier) compounds were synthesized in dimethylformamide (DMF) and ethanol (EtOH), denoted as Fe@MIL-DMF and Fe@MIL-EtOH. Carboxyl group functionalization of Fe3O4 suggested that sodium borohydride can promote more carboxyl groups decorated on the surface of Fe3O4 and resulted in more MIL-100(Fe) shell. Meanwhile, solvent DMF encouraged a greater MIL-100(Fe) layer coverage on Fe3O4 surface than EtOH, leading to a higher surface area and a greater adsorption ability for lead ion (Pb2+). Adsorption experiments displayed a monolayer absorption and Pb2+ was adsorbed by electrostatic interaction and coordination. Magnetic metal-organic frameworks Fe3O4@MIL-100(Fe) composites were synthesized in DMF and EtOH. Fe@MIL-DMF exhibited a higher surface area and a greater adsorption ability for Pb2+

For the application needs of histidine-rich protein separation, this study proposes to prepare a magnetic adsorbent enriched with copper ions and small particle size. Using a compression nebulizer, the magnetic + sodium alginate solution was broken into micrometer-sized droplets and cross-linked and cured with copper ion solution. The magnetic copper alginate microspheres (Cu2+-Alg@Fe3O4) were obtained with an average particle size of 7.1 mu m, a magnetic saturation intensity of 36.9 emu center dot g- 1, and a Cu2+ content of 149.2 mg center dot g- 1.The adsorption equilibrium time of the Cu2+-Alg@Fe3O4 microspheres on bovine hemoglobin(BHb) was 90 min, and the maximum adsorption amount was 4318.5 mg center dot g- 1. The Cu2+-Alg@Fe3O4 microspheres also showed stable and good adsorption performance in five cyclic adsorption experiments.

Extraction of low -concentration rare earths is one of the important paths for the sustainability of the rare earth industry. The research and development of materials suitable for the extraction of rare earth ions at low concentrations is of great significance. Currently, the application of solvent extraction in the rare earth production industry is highly mature. However, it is not economical to use it for the extraction of low concentration rare earths with problems of phase separation and organic phase loss. This work innovatively proposes to encapsulate the extractant and diluent in magnetic oleogel microspheres, which are obtained by solubilizing magnetic poly (phenyl divinylbenzene)(PS-DVB) microspheres with the extractant and diluent.. The magnetic PS-DVB microspheres of 3 - 16 mu m were prepared by suspension polymerisation, followed by encapsulation of di(2-ethylhexyl) phosphoric acid (D2EHPA) and dichloroethane in magnetic PS-DVB microspheres using emulsion swelling, and then magnetic oil -based gel microspheres containing D2EHPA with a particle size of 10 - 32 mu m were obtained. The magnetic oil -based gel microspheres containing D2EHPA consist of about 96 wt% liquid phase and about 4 wt% solid phase, with D2EHPA accounting for more than 4.19 wt%. The magnetic oil -based gel microspheres are very close to small oil droplets and are superparamagnetic. The magnetic oil -based gel microspheres containing D2EHPA could completely extract 60 ppm of scandium ions(Sc3+) under the conditions of O:A = 1:50,1:60,1:70, and the extraction equilibrium times were 6, 9 and 12 min, respectively. This extractant encapsulation scheme inherits the selectivity of traditional extractants while simultaneously preserving the advantages of rapid extraction by solvent extraction.

Recovery of low concentration Au(III) from industrial wastewater has both economic and environmental values. Therefore, it is of far-reaching significance to develop materials for efficient extraction of low-concentration Au(III). In this work, a novel microextraction scheme is proposed by combining the characteristics of both microextraction and extractant curing technique. Magnetic polystyrene microspheres were used as a container to encapsulate the extraction phase consisting of extractant(Aliquat 336) and diluent(1,2-dichloroethane). Superparamagnetic polystyrene microspheres with an average particle size of 3.3 μm and a magnetic saturation strength of 4.54 emu·g-1 were prepared by emulsification + suspension polymerization. Then Aliquat 336 and 1,2-dichloroethane were encapsulated into the magnetic polystyrene microspheres by the emulsion-swelling method, and magnetic oil-based gel microspheres containing Aliquat 336 with an average particle size of 14.2 μm were obtained. The magnetic oil-based gel microspheres containing Aliquat 336 consisted of 1,2-dichloroethane (81.73%), Aliquat 336 (11.52 wt.%), polystyrene (4.36 wt.%), and iron tetraoxide (1.69 wt.%). Using microspheres to extract Au(III) at concentrations ranging from 6.0 to 370.0 mg·L-1, the extraction equilibrium could be reached in 8 min with a small oil-water ratio (O:A=1:100), and the maximum loading of the microspheres to Au(III) was 33.5 mg·g-1. The magnetic oil-based gel microspheres containing Aliquat 336 maintained stable extraction performance over four cycles. In the solution where impurity ions (Ca2+, Fe3+, Cu2+, and Ni2+) coexisted, the concentration of the impurity ions was 4 ~ 20 times that of t Au(III), and the magnetic oil-based gel microspheres containing Aliquat 336 showed good selectivity for Au(III) extraction.

Superparamagnetic materials are considered to be the main materials for efficient purification of proteins by metal chelating affinity techniques. In this paper, we innovatively propose to atomize a suspension of carboxymethyl chitosan and magnetic Fe3O4 nanoparticles into micrometer droplets using a compressed nebulizer, while collecting and curing these atomized droplets with a container containing copper ion solution. After that, the magnetic carboxymethyl chitosan-copper microspheres(Fe3O4/CMCS-Cu2+) with hollow and porous structure were synthesized in one step. Characterization of the Fe3O4/CMCS-Cu2+ microspheres showed that they were superparamagnetic with a particle size of 1.11 - 2.55 mu m. The microspheres were featured with a hollow and porous structure, and the shell layer was covered with irregular pores with pore diameters of 10 - 50 nm. The contents of Cu in the microspheres were 0.0773 g/g. The equilibrium time for BHb adsorption by the Fe3O4/ CMCS-Cu2+ microspheres under the optimum experimental conditions was 60 min, and the maximum adsorption capacity was 10540 mg/g. The Fe3O4/CMCS-Cu2+ microsphere preparation method is simple and efficient.

The oilfield produced water (PW) treated by traditional process difficult to reduce the chemical oxygen demand COD value to below 50 mg/L. In this work, magnetic nano-Fe3O4 modified powdered coconut shell biochar was successfully prepared. The COD value of the PW was reduced from an initial value of 387 mg/L to 37 mg/L in 10 min of low speed mixing using magnetic nano-Fe3O4 modified powdered coconut shell biochar. In addition, the spent magnetic nano-Fe3O4 modified powdered coconut shell biochar can be regenerated by heating at 240 degrees C for 20 min. The regenerated magnetic nano-Fe3O4 modified powdered coconut shell biochar showed excellent adsorption properties, and the COD value of the PW was reduced to about 35 mg/L in all six recycles.

Magnetic biomaterials are widely used in the field of tissue engineering because of their functions such as drug delivery and targeted therapy. In this study, a magnetically responsive composite microcarrier was prepared through in situ polymerization of dopamine with Fe3O4 (MS) to form a complex. The magnetic composite microcarriers are paramagnetic and have certain magnetic responsiveness, suitable pore size porosity for cell growth, and good blood compatibility and biocompatibility. The bone marrow mesenchyml stem cells (BMSCs) were cultured on magnetic composite microcarriers, and a static magnetic field (SMF) was applied. The results showed that BMSCs adhered to the microcarriers proliferated under the action of horizontal and vertical forces. Magnetic composite microcarriers loaded with BMSCs were implanted into the SD rat model of cartilage defect, and a magnet was added to the operative side. After 12 weeks, cartilage regeneration was observed. The results of gross observation and histological immunostaining 1 month, 2 months, and 3 mounths after operation showed that the magnetic composite microcarriers of loaded cells promoted the early maturation of cartilage and collagen secretion, and the effect of cartilage repair was significantly better than that of the control group. Gait analysis showed that implanting magnetic composite microcarriers loaded with stem cells can reduce postoperative pain and promote limb recovery in SD rats. In conclusion, this study suggests that magnetic composite microcarriers are promising tissue-engineered scaffolds for cartilage regeneration and repair.

The application of immunomagnetic nanoparticles (IMNs) enables the isolation of rare circulating tumor cells (CTCs) from blood. Precise capture of CTCs with specific tumor phenotypes is achieved by attaching specific ligands to the surface of IMNs. The captured CTCs need to exhibit high bioactivity and proliferation ability for subsequent detection after co-culturing. The process of CTC enrichment using magnetic nanoparticles entails several issues, such as nonspecific capture and biological toxicity. Modifying the size of nanoparticles allows for altering the capture efficiency of nanoparticles for CTCs, as well as their biological activity and proliferation ability. In this study, two different sizes of magnetic nanoparticles are utilized to capture CTCs under diverse conditions. The capture efficiency of magnetic nanoparticles is assessed at different incubation times, along with determining the time needed to achieve and sustain the optimal capture efficiency. Fluorescence staining is employed to detect the bioactivity and cellular integrity of the captured CTCs. Subsequent to co-culturing with nanoparticles, the number of CTCs is measured every 24 h, and the survival rate is determined after 96 h.

Iron-based metal organic framework (MIL-100(Fe) (MIL: Materials of the Institut Lavoisier)) is attractive candi-date for adsorption, separation, and catalysis owing to their high surface area and permanent porosity. However, most of MIL-100(Fe)s only possess micropores and small mesopores, which prevent the transportation of large guest molecules and hinder their applications in macromolecules. In addition, corrosive hydrofluoric acid (HF)-free synthesis of MIL-100(Fe) can contribute to large scale production. Thus, constructing hierarchically porous HF-free MIL-100(Fe)s with large mesopores is highly desirable. In this study, six HF-free MIL-100(Fe)s were prepared in pure H2O and DMF using FeCl3, Fe(NO3)3 and Fe2(SO4)3 under hydrothermal/solvothermal condi-tions. The results indicated that applying FeCl3 as iron source and DMF as solvent can form pure MIL-100(Fe) (i.e., Cl-DMF) with abundant (79 vol%) mesopores (22 nm) and some macropores. The obtained samples were employed in removal of methylene blue (MB), rhodamine B (RhB) and methyl orange (MO) as dyes and chro-mium(VI) as metal ion. The Cl-DMF exhibited more excellent adsorption performance toward the macromolecular dye RhB compared to other five products. Adsorption of RhB onto Cl-DMF was obeyed the pseudo-second order and Freundlich isothermal models. Maximum adsorption capacity of RhB was 207 mg/g for Cl-DMF, which is considerably higher than other MIL-100(Fe)s reported. The adsorption mechanism investigation indicated that it can be related to a combination of physical adsorption and electrostatic reaction.

In this paper, an effective and sustainable treatment method for recycling chromium from sludge produced by magnetic flocculation was established. Chromium was extracted from sludge with hydrogen peroxide and sodium hypochlorite, and then, superparamagnetic ferroferric oxide nanoparticles (MPs) were recovered by magnetic separation. The recovery percentage of chromium with sodium hypochlorite was higher than that with hydrogen peroxide, and the maximum was 99.12%. With increasing MPs use times, the adsorption percentage of chromium decreased, but there was no significant change in the recovery percentage of chromium in sludge. The purity of the recovered sodium chromate crystals was 96.28%. The back-propagation algorithm was used to model chromium recovery. The correlation coefficient between the model prediction data and experimental data was 0.9990, and the average absolute error was 0.51. The maximum recovery percentage of chromium obtained from model prediction was 99.27%, and the corresponding optimal conditions were consistent with those of experiments.

MIL-100(Fe) with microporous structures is often synthesized under conventional hydrothermal conditions using iron ion and trimesic acid. The effect of H2O/dimethylformamide (DMF) mixtures, with variable H2O volume ratios, on the formation of MIL-100(Fe) was investigated under solvothermal conditions. Pure octahedral MIL-100(Fe) could only be formed in neat H2O or DMF. In most cases, the same reaction in mixed H2O/DMF solvents afforded goethite. When a small volume of H2O was used, morphology resembled coexisting octahedra of MIL-100(Fe) and hexagonal platelets of goethite. A subsequent increase in the H2O content yielded pure hexagonal platelets of goethite and then hexagonal bipyramidal structures of hematite. The surface area and pore volume of MIL-100(Fe) were higher than those of goethite. Dye adsorption tests revealed that 80% of methylene blue (MB) was adsorbed on MIL-100(Fe), synthesized in pure DMF, within 5 min, whereas only approximately 26% was adsorbed on MIL-100(Fe) synthesized in pure H2O. This can be attributed to the nanoscale hierarchically porous structures with macroporosity in the DMF-synthesized MIL-100(Fe) and enhanced fast diffusion and mass transfer of dye, which demonstrates its potential as an adsorbent for dye removal. Thus, this study provides a new option of solvent for the formation of nanoscale hierarchically porous MIL-100(Fe) with improved performance in various practical applications.

It is a challenging problem that develops a low-cost, efficient and sustainable technology in order to remove heavy metals and organic contaminants in the practical wastewater. Herein, a novel recyclable Fe3O4/BiVO4/CuS (FBCu) heterojunction photocatalyst was facilely fabricated by a method, coating CuS nanoparticles on the surface of Fe3O4 and BiVO4 simultaneously. FBCu composite not only has the ability to degrade Cr(VI) or methylene blue (MB) alone under visible light irradiation, but also exhibits higher photocatalytic ability in simultaneously removing Cr(VI) and MB mixed pollutants. The superior photocatalytic performance of FBCu is related to the formation of p-n heterojunction, which extends the spectral response and facilitates the efficiency of charge carriers separation and utilization. Moreover, FBCu exhibits satisfactory properties of reusability and stability after five cycling experiments in the Cr(VI)-MB coexistence system. Furthermore, the detailed mechanism for simultaneous removal of mixed pollutants was proposed and verified by DRS results, photoelectrochemical analysis, scavenger experiments and electron spin resonance determination. This work provides a recyclable photocatalyst with eco-friendliness and multifunctional applications in water pollution. (C) 2021 Elsevier B.V. All rights reserved.

A simple and effective method for chromium removal in wastewater by using magnetic nanoparticles (MPs, Fe3O4) in the gradient magnetic field was studied in this paper. The optimum process conditions were determined by testing the pH, added MPs dosage, stirring time and standing time. The maximum chromium adsorption efficiency (E) obtained by experiment was 99.33%. The back-propagation (BP) algorithm optimized by particle swarm optimization (PSO) was used to model chromium adsorption. The topology of BP was determined to be 4-8-1. The optimization process converged quickly with a high target accuracy, and the best training performance was 0.0098601 at 13 epochs for BP algorithm. The Pearson correlation coefficient (P) between the experimental data and the data predicted by PSO-BP model was 0.99914, with the mean absolute error (MAE) being 0.1974, and the maximum E predicted by PSO-BP model was 99.88%.