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Co2+‐ZIF‐67 metal‐organic framework nanoparticles (NMOFs), act as nanozymes catalyzing diverse processes, including peroxidase, oxidase, and catalase activities. Peroxidase activities are reflected by the nanozyme‐catalyzed H2O2 oxidation of dopamine to aminochrome, the H2O2 oxidation of NADH to NAD+, the H2O2‐catalyzed generation of chemiluminescence through oxidation of luminol, and the H2O2‐mediated oxidation of aniline to polyaniline. Oxidase activities of the nanozyme are demonstrated by the Co2+‐ZIF‐67 NMOFs catalyzed aerobic oxidation of dopamine to aminochrome and of NADH to NAD+, and catalase activities of the nanozyme are reflected by the catalytic decomposition of H2O2. Moreover, the Co2+‐ZIF‐67 catalyzed oxidation of aniline to polyaniline (PAN) by H2O2 is accompanied by the coating of NMOFs with PAN to yield a Co2+‐ZIF‐67/PAN hybrid material. Coating the particles in the presence of guest substrates leads to molecular imprinted PAN matrices revealing enhanced ZIF‐67 catalyzed transformations as compared to non‐imprinted PAN matrices. This is demonstrated by imprinting of 2,2′‐azinobis(3‐ethylbenzothiazoline‐6‐sulfonic acid), ABTS2−, in the PAN coating and the 3.3‐fold enhanced catalyzed oxidation of ABTS2− by H2O2, as compared to the non‐imprinted PAN hybrid composite. Moreover, imprinting of L‐/D‐DOPA in the PAN coating of Co2+‐ZIF‐67 NMOFs leads to chiro‐selective H2O2‐guided oxidation of L‐/D‐DOPA to dopachrome by the NMOFs/PAN composite. [ABSTRACT FROM AUTHOR]

Photoluminescent (PL) carbon quantum dots (CQDs) were prepared successfully using a facile and green procedure. They exhibited striking blue fluorescence and excellent optical properties, with a quantum yield as high as 61.44%. Due to the fluorescence quenching effect and the stronger complexing ability of the phosphoric acid group of 1‐hydroxyethane‐1,1‐diphosphonic acid (HEDP) to Fe3+, CQDs doped with Fe3+ were adequately constructed as an efficient and sensitive fluorescent probe for HEDP‐specific sensing. The proposed fluorescent probe had a sensitive and rapid response in the range 5–70 μM. Furthermore, quantitative molecular surface (QMS) analysis based on the Multiwfn program was applied to explore the complexation mode of HEDP and metal ions. The distribution of electrostatic potential (ESP), average local ionization energy (ALIE), the minimum value points and the position of the lone pair electrons on the surface of molecular van der Waals were further determined. More strikingly, this experiment achieved the quantitative detection of water‐soluble phosphonate‐HEDP, for the first time using fluorescence spectrometry. It has been proved to be an effective and intuitive sensing method for the detection of HEDP in real samples. [ABSTRACT FROM AUTHOR]

BACKGROUND: Copper is a heavy metal that is widely available in nature and has attracted people's attention because of its toxicity and difficult biodegradability. Using modified montmorillonite to adsorb copper ions (Cu2+) was widely adopted because of its simple operation, high efficiency, and easy availability. RESULTS: Na‐montmorillonite (Na‐Mt) was modified through a Gemini surfactant (containing four ammonium cations) to explore the adsorption capacity for Cu2+ in aqueous media. The resulting product is called G‐Mt. FT‐IR XRDBET results indicated that Gemini surfactant has significantly intercalated into the montmorillonite interlayers. The results ofbatch adsorption experiments presented that the amount of adsorbed (qe) depend on pH value and qe (G‐Mt) can reach to 29.30 mg/g, which was greater than that of Na‐Mt (25.30 mg/g) when pH is 6.0 and initial Cu2+ concentration is 75 mg/L. The experimental data matched well with Langmuir isotherm. The thermodynamic analysis implied that adsorption of Cu2+ was endothermic and a spontaneous process. Molecular dynamics (MD) models were carried out to investigate the microstructure and kinetic information of Gemini cations in the interlayer of G‐Mt. The results elucidated that the distribution and interaction characteristic of ammonium cations of Gemini surfactant including four ammonium cations were completely different from that of the quaternary ammonium salts containing asingle ammonium cation. CONCLUSION: Generally, considering the comprehensive performances, polyamine Gemini surfactant to modify montmorillonite can improve its ability to adsorb Cu2+. The micro environment in the interlayer space and adsorption properties of G‐Mt on Cu2+, which will improve the potential utilization of G‐Mt in soil remediation or wastewater treatment. © 2019 Society of Chemical Industry [ABSTRACT FROM AUTHOR]

The vacuum tube method has been used for the construction of nondestructive and physically stable graphitic carbon nitride/graphene nanoplatelet composites and their photocatalytic behavior studied by measuring different photoactivities, such as photocurrent, photoluminescence, and the photodegradation of tetracycline hydrochloride under visible‐light irradiation. The formation of a heterojunction was confirmed by XRD, TEM, SEM, FTIR, XPS, and Raman spectroscopy. The results of this research indicate that the vacuum tube method is a facile, economic, and environmentally friendly approach to the preparation of composites. An ion‐trapping experiment indicated that, under visible light, the most effective photocatalyst generated the superoxide radical (O2·–) and holes (h+) to achieve the complete degradation of tetracycline hydrochloride. [ABSTRACT FROM AUTHOR]