Fusheng Zhang

Efficient adsorption and separation of dysprosium from NdFeB magnets in an acidic system by ion imprinted mesoporous silica sealed in a dialysis bag

A straightforward, one-pot approach for novel ion imprinted mesoporous silica materials (IMS) has been developed by co-condensation. IMS was used for the recovery of dysprosium through solid–liquid extraction in an acidic system. The dysprosium adsorption of IMS was efficiently modeled using a pseudo-second order rate equation. The initial kinetics of adsorption was fast, and almost complete adsorption was observed after 150 min. Adsorption isotherms were efficiently modeled using the Langmuir equation. The adsorption capacity of IMS toward dysprosium was 22.33 mg g−1 at pH = 2.0, which was apparently greater than the adsorption capacity of non-imprinted materials at pH = 5.0. The value of the imprint factor at pH = 2.0 was higher than the other pH obviously. The distribution coefficient relative to dysprosium was 539 mL g−1, which was significantly higher than that of other rare earth ions. IMS demonstrates enhanced selectivity towards dysprosium compared to non-imprinted materials in an acidic solution via solid–liquid extraction, which substantially improves the selective extraction process and provides a greener alternative to liquid–liquid extraction. In addition, the materials demonstrated a high degree of reusability over five extraction–stripping cycles, enhancing their potential for application in real rare earth metal recycling in acidic systems.

Efficient Recovery of Neodymium in Acidic System by Free-Standing Dual-Template Docking Oriented Ionic Imprinted Mesoporous Films

Neodymium (Nd) is critical component of sintered neodymium magnets. Separation of Nd from consumer magnets has attracted a widespread attention. In this paper, we presented free-standing ionic imprinted mesoporous film materials for facile and highly efficient targeted separation of Nd from permanent magnets by dual-template docking oriented ionic imprinting (DTD-OII) method. DTD-OII is based on dual-template docking oriented molecular imprinting. Compared with conventional imprinting, this novel strategy does not need extra steps, but significantly advance imprinted efficiency. With optimization of functional monomer, our free-standing dual-template docking oriented ionic imprinted mesoporous films exhibit excellent adsorption of Nd by solid-liquid extraction. The Nd adsorption capacity for optimized films was 34.98 mg g-1 under pH = 3.0. The distribution coefficient of Nd was 636 mL g-1, which indicates films possess significantly selectivity of Nd. In addition, efficient dual-template docking oriented ionic imprinting makes films demonstrating an outstanding of reusability by cycle test, which appreciating their potential for industrial application.

Preparation of diethylenetriamine-modified magnetic chitosan nanoparticles for adsorption of rare-earth metal ions

The separation and reutilization of rare-earth metals are flourishing in numerous advanced technologies, yet the development of a sustainable method to conveniently adsorb rare-earth metal ions remains a challenge waiting for a breakthrough. Chitosan, as a natural and biodegradable material, has been frequently studied to synthesize adsorbents for adsorption of rare-earth metals. In this study, a magnetic bio-adsorbent Fe3O4-C18-chitosan-DETA (FCCD) composite was first prepared via a simple “surface deposition-stepwise grafting” method. The results show that the adsorption capacity of Dy3+, Nd3+, and Er3+ to the as-obtained FCCD is about 28.3, 27.1, and 30.6 mg g−1, respectively, at 25 °C and optimal pH (7.0). The kinetics data followed a pseudo-second-order equation, and the Langmuir equation fitted well to the adsorption isotherms. Subsequently, the as-synthesized adsorbent (FCCD) can be successfully regenerated and recycled for 5 cycles using hydrochloric acid as the eluent. This study develops a promising candidate for practical application in the recovery of rare-earth metal ions owing to its magnetic separation, good acid-resistance, and excellent adsorption capacity.

A lanthanide complex-based molecularly imprinted luminescence probe for rapid and selective determination of λ-cyhalothrin in the environment

Molecularly imprinted polymers cladded lanthanide complexes were synthesized via precipitation polymerization. The luminescent molecularly imprinted polymers were characterized by scanning electron microscopy, Fourier transform infrared spectroscopy and thermogravimetric analysis. The optical properties of the imprinted polymers were determined by fluorescence spectroscopy. Due to the highly selective cavities of the surface imprinted layer of the polymers, the imprinted polymers could be applied to the rapid, selective and sensitive determination of λ-cyhalothrin. Based on the quenching mechanism, the quantitative determination λ-cyhalothrin was proposed using the luminescent molecularly imprinted polymers as a fluoroprobe. Under the optimized experimental conditions, our fluoroprobe was successfully used for the selective and rapid recognition of λ-cyhalothrin. The fluorescent intensity of the fluoroprobe gave a linear response in the 10–100 μM concentration range with a correlation coefficient of 0.9963. In addition, the luminescence probe was proven to be suitable for the determination of λ-cyhalothrin residues in real environmental examples.

Dual-template docking oriented ionic imprinted bilayer mesoporous films with efficient recovery of neodymium and dysprosium

Rare earth elements (REEs) are critical materials to many cutting-edge technologies but are difficult to separate from one another because of their chemical similarity. We present ionic imprinted mesoporous bilayer films (IIBFs) as an ideal adsorbent for selective separation of neodymium (Nd) and dysprosium (Dy) from sintered neodymium magnets. IIBFs were prepared according to dual-template docking oriented ionic imprinting (DTD-OII). Due to different imprinted compositions of bilayer films, IIBFs exhibited high specific surface area, fast binding equilibrium, and Janus properties for simultaneous selective adsorption of different rare earth ions, which made our imprinted bilayer mesoporous films a specialized adsorbent for adsorption of Nd(III) and Dy(III) at the same time. The adsorption capacities of optimized IIBFs were 17.50 mg g-1 for Dy(III) and 12.15 mg g-1 for Nd(III) at pH = 4.0. Moreover, we grafted thermo-responsive polymer on the one surface of IIBFs to realize controlled release of Nd(III) and Dy(III) by temperature. IIBFs demonstrate a high degree of reusability by cycling experiments by DTD-OII, which develop their promising applications for the REE recycling and separation industry.