Dual‐template crown ether‐functionalized hierarchical porous silica: Preparation and application for adsorption of energy metal lithium

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Calixarenes have been drawing tremendous interest due to their special structure, superior properties and numerous applications. In this work, a novel adsorbent material, calix[4]arenes functionalized dual‐imprinted mesoporous film (DIMFs) for the simultaneous selective recovery of Li(I) and Rb(I), was prepared via surface ionic imprinting. Compared with ordinary adsorbent materials, the synthesis process of the films used a cheap bio‐template and did not require extra steps but significantly enhances adsorption properties. The morphology and structure of prepared DIMFs were characterized by scanning electron microscopy, transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FT‐IR) and nitrogen adsorption–desorption measurements. Adsorption parameters (pH and temperature), adsorption kinetics and adsorption isotherms of the DIMFs were investigated by adsorption experiments. This novel adsorbent has inorganic–organic hybrid frameworks, high specific surface area and uniform pore size. The Langmuir and Freundlich isotherms, pseudo‐first‐order and pseudo‐second‐order kinetics of DIMFs were investigated; suggesting that the adsorption data well fits the Langmuir isotherm model, and the adsorption kinetics can be described by the pseudo‐second‐order kinetic model. In addition, dual‐imprinted mesoporous film exhibited superior selectivity for Li(I) and Rb(I). Cycle test demonstrated an outstanding of reusability, which appreciating their potential for industrial application.

Calix[4]arenes functionalized dual‐imprinted mesoporous film for the simultaneous selective recovery of lithium and rubidium

Wang

Yang

et al. 2018

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Engineered mesoporous ionic‐modified γ‐Fe₂O₃@hydroxyapatite decorated with palladium nanoparticles and its catalytic properties in water

Pashaei

Mehdipour

Azaroon

2018

A new mesoporous organic-inorganic nanocomposite was formulated and then used as stabilizer and support for the preparation of palladium nanoparticles (Pd NPs). The properties and structure of Pd NPs immobilized on prepared 1,4-diazabicyclo[2.2.2]octane (DABCO) chemically tagged on mesoporous γ-Fe 2 O 3 @hydroxyapatite (ionic modified (IM)-MHA) were investigated using various techniques. The synergistic effects of the combined properties of MHA, DABCO and Pd NPs, and catalytic activity of γ-Fe 2 O 3 @hydroxyapatite-DABCO-Pd (IM-MHA-Pd) were investigated for the Heck cross-coupling reaction in aqueous media. The appropriate surface area and pore size of mesoporous IM-MHA nanocomposite can provide a favourable hard template for immobilization of Pd NPs. The loading level of Pd in the nanocatalyst was 0.51 mmol g −1 . DABCO bonded to the MHA surface acts as a Pd NP stabilizer and can also lead to colloidal stability of the nanocomposite in aqueous solution. The results reveal that IM-MHA-Pd is highly efficient for coupling reactions of a wide range of aryl halides with olefins under green conditions. The superparamagnetic nature of the nanocomposite means that the catalyst to be easily separated from solution through magnetic decantation, and the catalytic activity of the recycled IM-MHA-Pd showed almost no appreciable loss even after six consecutive runs.KEYWORDS aqueous media, Heck coupling reaction, mesoporous ionic-modified γ-Fe 2 O 3 @hydroxyapatite, palladium nanoparticle, sustainable organometallic platform

Simultaneous adsorption of Li(I) and Rb(I) by dual crown ethers modified magnetic ion imprinting polymers

et al. 2019

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With the gradual exhaustion of land mineral resources, oceans and lakes have attracted world attention because they are abundant in inorganic mineral resources including lithium, potassium, rubidium and cesium. Lithium is becoming the key material in manufacturing of primary and secondary batteries used in various portable devices and hybrid/electric vehicles. Rubidium has been widely applied inglobal positioning satellites, magneto‐optic modulators, solid‐state lasers, phosphors, and glass manufacturing. In this work, a novel dual‐functional magnetic ion imprinting polymer (Fe3O4@SiO2@IIPs) powder was prepared using 12‐crown‐4 (12C4) and 18‐crown‐6 (18C6) as functional monomer, and characterized by FT‐IR, elemental analysis, XRD, TGA, SEM and TEM. The adsorption performance of Fe3O4@SiO2@IIPs for simultaneous adsorption of lithium and rubidium from simulative salt lakes was evaluated by batches of experiments at various pH values, contact time, and initial concentrations. Kinetic experiments show that the adsorption process followed the pseudo second order kinetic model. Langmuir adsorption isotherm model and Freundlich adsorption equilibrium data were fitted; the results show that Langmuir isotherm model is more suitable for the adsorption process. Additionally, Fe3O4@SiO2@IIPs exhibit specificity towards Li(I) and Rb(I) and low competitive behavior with Na(I), K(I) and Mg (II). Additionally, the selectivity properties, reusability and adsorption thermodynamic were also investigated. The obtained results show that the prepared Fe3O4@SiO2@IIPs material remains high adsorption capacities after five cycles, exhibits excellent abilities to simultaneously and selectively recover Li+ and Rb+ and have a promising application in the simultaneous adsorption of lithium and rubidium ions.