Multifunctional graphene oxide (GO)/chitosan (CS) aerogel microspheres (GCAMs) with honeycomb-cobweb and radially oriented microchannel structures are prepared by combining electrospraying with ...freeze-casting to optimize adsorption performances of heavy metal ions and soluble organic pollutants. The GCAMs exhibit superior adsorption capacities of heavy metal ions of Pb(II), Cu(II), and Cr(VI), cationic dyes of methylene blue (MB) and Rhodamine B, anionic dyes of methyl orange and Eosin Y, and phenol. It takes only 5 min to reach 82 and 89% of equilibrium adsorption capacities for Cr(VI) (292.8 mg g–1) and MB (584.6 mg g–1), respectively, much shorter than the adsorption equilibrium time (75 h) of a GO/CS monolith. More importantly, the GCAMs maintain excellent adsorption capacity for six cycles of adsorption–desorption. The broad-spectrum, rapid, and reusable adsorption performance makes the GCAMs promising for highly efficient water treatments.
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•Novel ternary g-C3N4/α-Fe2O3/Bi3TaO7 heterojunction was synthesized for the first time.•Catalyst presented superior visible-light catalytic activity for ciprofloxacin ...degradation.•Dual Z-scheme system resulted in efficient charge transfer and strong redox capacity.•Catalyst could be easily separated from aqueous solution by an external magnetic field.
Insufficient photocatalytic activity and poor recyclability are considered as two main factors that limit the further application of photocatalysts in environmental remediation. Herein, a new magnetic g-C3N4/α-Fe2O3/Bi3TaO7 (CN/FO/BTO) heterojunction with dual Z-scheme system was first synthesized via an ultrasound-assisted calcination process. The results showed that the removal efficiency of ciprofloxacin (CIP) by optimized CN/FO/BTO heterojunction could reach 95.6% within 120 min illumination of visible light, which was 6.1, 15.9, 5.2, 3.7 and 2.3 times as much as that of single CN, FO, BTO, binary CN/FO and CN/BTO, respectively. Characterization analysis indicated that the improved photocatalytic activity derived from the synergistic effects of the three components, including the dispersion of FO and BTO by CN sheet, the enhanced light absorption of CN by addition of FO and BTO, and the reduced photogenerated charge recombination by their intimate contact. Further mechanism study revealed that the dual Z-scheme system of CN/FO/BTO leaded to efficient photoexcited carrier separation and strong redox capacity, in which •O2– and •OH were main radicals during photocatalytic process. Meanwhile, CN/FO/BTO possessed supreme adaptability to pH as well as co-existing matters, favorable magnetic separation property and excellent stability, making it a potential candidate for environmental remediation applications.
Acid is a catalyst for making and breaking poly(disulfide)s. In their Research Article (e202215329), Da‐Hui Qu et al. report that the disulfide bonds of 1,2‐dithiolanes can be activated by acid ...protonation, enabling a robust and protection‐free methodology to prepare long polymers with chemical recyclability.
•A novel UIO-66@PDA/SAhydrogel composite bead soil conditioner with water retention and adsorption properties was developed.•The water retention experiment demonstrates that this hydrogel composite ...bead owns a good water retention performance.•Adsorption experiments showed that this hydrogel composite bead can effectively adsorbmethylene blue at pH=7 and T = 298.15 K.
A hydrogel composite bead soil conditioner with water retention, adsorption and recyclability properties was developed. The core material of the beads was metal organic framework material UIO-66, while the shell material consisted of polydopamine (PDA) and sodium alginate (SA). Characterization techniques such as Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD) and Brunauer-Emmett-Teller (BET) were used to analyze and demonstrate the structure and composition of the composites. The water retention experiment and soil water loss experiments showed that the UIO-66@PDA/SA hydrogel composite beads had a water retention rate of 10.96 % after 300 min and a water evaporation rate of less than 1 % in soil within 4 h, indicating good water retention performance. Adsorption experiments showed that the UIO-66@PDA/SA hydrogel composite beads effectively adsorbed methylene blue (MB) with an equilibrium adsorption amount of 213.79 mg/g. This was a 72.6 % increase compared to pure sodium alginate (SA). They had the highest adsorption capacity of 240.79 mg/g at pH=9 and T = 298.15 K, indicating that alkaline conditions favored the adsorption process. The adsorption process followed the Pesudo-second-order model and exhibited characteristics of the Langmuir adsorption isotherm model. In addition, dynamic adsorption analysis demonstrated that the UIO-66@PDA/SA hydrogel composite beads owned efficient recyclability, and the relative adsorption efficiency remained above 90 % after 4 cycles. This technology offers a cost-effective, uncomplicated, and efficient solution for promoting a healthy soil environment and facilitating agricultural applications.
The last few years have seen huge growing interest in the heterogenisation of molecular catalysts since it allows combining the advantages of homogeneous and heterogeneous catalyses. Besides bringing ...recyclability, the immobilisation of the catalyst may increase its stability while allowing tuning its selectivity. In this respect, Metal–Organic Frameworks (MOFs) attract evergrowing interest as a platform for their confinement within their pores or channels. In this review, Cat@MOF composites wherein molecular catalysts (Cats) are immobilised into MOFs through non-covalent interactions with their host are reviewed thoroughly. Polyoxometalates (POMs) and other metal-based complexes as immobilised molecular species are covered. In the first part, the different synthetic methods and analytical tools are described. A critical analysis of the various physico-chemical methods available to characterise the Cat@MOF composites is provided – particular attention being paid toward their pertinence to the investigation of the content, the position and the stability of the catalyst within the MOF. Besides, the focus is on non-conventional techniques such as the Pair Distribution Function (PDF) method and a section is dedicated to the contribution of DFT calculations. In the second part, the applications of these materials in the fields of catalysis, including oxidation and reduction reactions, acid–base catalysis, and photo- and electrocatalysis, are detailed.
The selective aerobic oxidative coupling of amines under mild conditions is an important laboratory and commercial procedure yet a great challenge. In this work, a porphyrinic metal-organic ...framework, PCN-222, was employed to catalyze the reaction. Upon visible light irradiation, the semiconductor-like behavior of PCN-222 initiates charge separation, evidently generating oxygen-centered active sites in Zr-oxo clusters indicated by enhanced porphyrin π-cation radical signals. The photogenerated electrons and holes further activate oxygen and amines, respectively, to give the corresponding redox products, both of which have been detected for the first time. The porphyrin motifs generate singlet oxygen based on energy transfer to further promote the reaction. As a result, PCN-222 exhibits excellent photocatalytic activity, selectivity and recyclability, far superior to its organic counterpart, for the reaction under ambient conditions
combined energy and charge transfer.
In this study, carbon nanodots (C-dots)/WO3 photocatalysts were prepared via a two-step hydrothermal method. The morphologies and optical properties of the as-prepared materials were investigated. ...Compared with the prepared WO3 and C-dots, the C-dots/WO3 possessed stronger photocatalytic capability and excellent recyclability for photocatalytic elimination of Rhodamine B. For example, the achieved first order reaction rate constant of 0.01942 min−1 for C-dots/WO3 was ∼7.7 times higher than that of the prepared WO3. The enhanced photocatalytic activity of C-dots/WO3 was attributed to the enhanced light harvesting ability and efficient spatial separation of photo-excited electron–hole pairs resulting from the synergistic effect of WO3 and C-dots. The high photocatalytic activity of C-dots/WO3 remained unchanged even after 3 cycles of use. Meanwhile, a possible mechanism of C-dots/WO3 for the enhanced photocatalytic activity was proposed.
The current study focused on adsorption of dimethoate by using highly adsorptive porous membrane based on metal organic framework@cellulose acetate (Cu-BTC@CA). The porous Cu-BTC@CA membrane was ...prepared in two steps; formation of porous CA membrane and secondly, Cu-BTC was in-situ synthesized within the porous CA membrane. The preparation was performed to incorporate different ratios of Cu-BTC (20–60%) within the CA membrane to study their efficiency in the adsorption of dimethoate. Micro-crystals Cu-BTC was successfully immobilized in the macroporous CA membrane with pore diameter of 112.6–496.0 nm. The BET surface area was significantly increased from 78.4 m2/g for CA membrane to 965.8 m2/g for 40% Cu-BTC@CA membrane. Adsorption of dimethoate upon the synthesized membrane was fitted well to Langmuir isotherm and pseudo-second order model. The adsorption capacity was observably enhanced from 207.8 mg/g for CA membrane to 282.3–321.9 mg/g for Cu-BTC@CA membrane. Incorporation of 40% Cu-BTC resulted in acceleration of the dimethoate adsorption by factor of 2.1. The applied membrane showed quite good recyclability and the adsorption efficiency was reduced by 22.5% after 5 recycles. The synthesized Cu-BTC@CA membrane could be promisingly applied in the effective removal of pesticides with sufficient recoverability, and in general environmental purposes.
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•Macroporous membrane based on Cu-BTC@CA membrane was prepared.•Surface area for porous 40% Cu-BTC@CA membrane was quite high (965.8 m2/g).•The porous membrane showed high adsorption capacity of 282.3 – 321.9 mg/g.•By using of 40%Cu-BTC@CA, the adsorption was accelerated by factor of 2.1.•Adsorption efficiency of membrane was diminished by 22.5% after 5 reusing cycles.
•Green approach for nano-phase transformation from γ-Fe2O3 to Fe3O4 by tannic acid.•Gram-level yield and the high NIR photothermal conversion (η = 35.7%) in Fe3O4 NPs.•Improved absorption with the ...interfacial charge transfer between polyphenol and iron.•Efficient sterilization by heat through bacterial FimH adhesion.•Recyclable photothermal bactericide for medical/environmental microorganism control.
An iron oxide (Fe3O4)-mediated photothermal treatment has been revealed as the next generation of noninvasive and nontoxic theranostic nanoagents compared with other inorganic nanoparticles. Nevertheless, iron oxide with NIR-mediated activity is limited by its inability to be mass produced and its long-lasting photon-to-thermal conversion. Herein, we develop using a green reagent, tannic acid (TNA), which assisted hydrothermal reaction to generate black Fe3O4 nanoparticles by using commercially available nanoptical γ-Fe2O3 NPs as a starting material. The phase transformation from γ-Fe2O3 to the reduced form of Fe3O4 is assisted by TNA in the solution phase. Based on the formation of the interfacial TNA-Fe chelation and the delicate phase transformation from γ-Fe2O3 to Fe3O4 structures, the colloidal black Fe3O4 nanoparticles exhibit broad absorption that covers the visible and NIR wavelengths. Specific interfacial ligand-to-metal charge transfers between the TNA and iron ions at the surface of iron oxide nanoparticles, improves the absorbance and leads to the highest photon-to-thermal conversion (η = 35.7%) at 808 nm compared with other iron oxide nanomaterials. After modifying d-mannose (MA) onto the surface of the Fe3O4@TNA nanoparticles, the local heat can efficiently transfer from the Fe3O4@TNA nanoparticles to the vicinity of the bacterial FimH adhesion molecule, causing extensive photothermal injury to O157:H7 and ESBL strain bacteria with over 99% cell death at 200 ppmFe with 808 nm light at 2.25 mW/cm2. Based on its robust photostability, Fe3O4@TNA@MA shows photothermal bactericidal recyclability through magnetic collection, adhesion, and photothermal processes.
Permanently cross-linked networks confer chemical and mechanical stability to cross-linked elastomers, making their recycling a serious environmental issue. Recyclable covalently crosslinked ...elastomers have recently been developed by building covalently adaptive networks in elastomers. Here, we demonstrate a simple and general strategy to construct covalent adaptable networks with mechanical robustness, self-healing, shape memory, and recyclability. The dynamic boronic ester linkage between silica and epoxidized natural rubber endows the material with high stretchability and high tensile strength. The boronic ester bond exchange enables the cross-linked network to achieve self-healing, remodeling, and shape memory through network structural rearrangement. The materials can be recovered by hot pressing or dissolution, and the structure of the sample recovered by dissolution remains basically unchanged. Furthermore, a self-healing flexible electronic device can be fabricated by spraying conductive graphite on the surface of these elastomers. Considering that this interfacial boronic ester bond cross-linking can be easily achieved between different commercial epoxy polymers and hydroxyl-rich nanoparticles, we believe that this work has great potential in the development of rubber-based vitrimer elastomers and flexible wearable devices.
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