Search

A novel graphene-based composite, 5-methyl-1,3,4-thiadiazol-2-amine (MTA) covalently functionalized graphene oxide (GO-MTA), was rationally developed and used for the selective sorption of Ga3+ from aqueous solutions, showing a higher adsorption capacity (48.20 mg g−1) toward Ga3+ than In3+ (15.41 mg g−1) and Sc3+ (~0 mg g−1). The adsorption experiment's parameters, such as the contact time, temperature, initial Ga3+ concentration, solution pH, and desorption solvent, were investigated. Under optimized conditions, the GO-MTA composite displayed the highest adsorption capacity of 55.6 mg g−1 toward Ga3+. Moreover, a possible adsorption mechanism was proposed using various characterization methods, including scanning electron microscopy (SEM) equipped with X-ray energy-dispersive spectroscopy (EDS), elemental mapping analysis, Fourier transform infrared (FT-IR) spectroscopy, and X-ray photoelectron spectroscopy (XPS). Ga3+ adsorption with the GO-MTA composite could be better described by the linear pseudo-second-order kinetic model (R2 = 0.962), suggesting that the rate-limiting step may be chemical sorption or chemisorption through the sharing or exchange of electrons between the adsorbent and the adsorbate. Importantly, the calculated qe value (55.066 mg g−1) is closer to the experimental result (55.60 mg g−1). The well-fitted linear Langmuir isothermal model (R2 = 0.972~0.997) confirmed that an interfacial monolayer and cooperative adsorption occur on a heterogeneous surface. The results showed that the GO-MTA composite might be a potential adsorbent for the enrichment and/or separation of Ga3+ at low or ultra-low concentrations in aqueous solutions. [ABSTRACT FROM AUTHOR]

Highly efficient and low-cost materials for the degradation of organic dyes in wastewater remain the focus of environmental protection and water pollution control, in which, nanozymes have been at the forefront for the development of a new platform and aroused more and more attention. In this work, a nanoceria@shaddock peel-derived nanocomposite (Ce@CSP) with excellent peroxidase-like performance in methyl violet (MV) degradation as well as ascorbic acid (AA) detection was synthesized by a simple one step in situ pyrolysis of cerium ammonium nitrate (Ce(NH4)2(NO3)6) and pretreated shaddock peel. By means of the cooperative-reinforcing peroxidase-like activity of the porous carbon material originating from shaddock peel (CSP) and the loaded CeO2 nanoparticle, the obtained nanozyme Ce@CSP displayed a superior catalytic ability in the catalyzed oxidation of the chromogenic substrate 3,3′,5,5′-tetramethylbenzidine (TMB) in the presence of H2O2. Specifically, a synergetic absorbent property was also demonstrated by the porous carbon material, bringing the target molecules in close proximity to the nanozyme catalyst and therefore enabling effective decoloration of MV and colorimetric detection of AA with a linear range of 1.6–17.3 μM and a detection limit of 1.07 μM. The current work has realized effective decoloration of MV in real water samples and provided a wide range of potential applications of low-cost and eco-friendly materials in organic dye treatment. [ABSTRACT FROM AUTHOR]

A 3D cauliflower-like Ni foam on titanium plate (Ni foam/TP) shows high electrocatalytic performance for ambient ammonia (NH3) synthesis via nitrite (NO2−) reduction. In 0.1 M phosphate-buffered saline solution with 0.1 M NO2−, such Ni foam/TP attains a high NH3 Faradaic efficiency (FE) of 95.9% and a large NH3 yield of 742.7 μmol h−1 cm−2 at −0.8 V. Its Zn–NO2− battery offers a high power density of 6.2 mW cm−2 and an NH3 FE of 90.1%. [ABSTRACT FROM AUTHOR]

In comparison with the poor stability, high cost, and difficult preparation of conventional natural enzymes, nanozymes have the obvious advantages of excellent stability, high catalytic activity, multifunctionality, and large-scale preparation. Herein, a series of Fe3O4 NPs-based magnetic composite with dual enzyme-like activities (peroxidase and oxidase) were successfully synthesized by the microwave-assisted method. Among them, the Fe3O4/Ag Au nanocomposite showed the highest peroxidase-like activity due to the synergistic catalytic effect of Ag and Au bimetallic modifications. Enzyme kinetic studies revealed good kinetic parameters of the Fe3O4/Ag Au nanocomposite for peroxidase, and it also exhibited a higher affinity for TMB compared to natural horseradish peroxidase. In addition, a method for effective dye degradation and selective detection of glutathione was constructed based on its peroxidase-like activity. Importantly, the remarkable magnetic separation property and the outstanding stability proved the extensive application prospects of the nanozymes in the remediation of water pollution and some biomarker-specific detection. [ABSTRACT FROM AUTHOR]