The core–shell structure UiO-66-NH 2 @Ni-MOF was prepared by in-diffusion growth of 2D Ni-MOF on UiO-66-NH 2 using PVP (polyvinylpyrrolidone) as a structural guide. It was applied to the adsorption of U(VI) in aqueous solution. The materials were characterized by powder X-ray diffraction (PXRD), Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and energy dispersive spectrometer (EDS). The UiO-66-NH 2 @Ni-MOF adsorption to U(VI) was investigated experimentally. The study showed that the adsorption of U(VI) onto UiO-66-NH 2 @Ni-MOF was endothermic and spontaneous. At pH 5.00 and 308 K, the adsorption capacity was 581.40 mg/g according to Langmuir model. In addition, the adsorption process can be described by the pseudo-second-order kinetic model. The adsorption capacity was kept at 83.83% of its original one after five sorption–desorption cycles, a promising indication for repetitive usage.
Here we report a general approach for synthesizing size/morphology-controlled NH2-Ni-MOFs by optimizing the solvent composition in the reaction system, and their correlating catalytic performances are clearly explored for the first time. Interestingly, the electrocatalytic performance was found to increase 2.7 fold when the particle size is reduced from 1.5 μm for NH2-Ni-MOF(a) to 300 nm for NH2-Ni-MOF(c). Subsequently, this work exhibits an example of a high-performance NH2-Ni-MOF(c) electrocatalyst for application in constructing an electrochemical aptasensor to achieve sensitive C-reactive protein (CRP) detection based on an aptamer binding induced DNA walker–antibody sandwich assay. The proposed aptasensor shows a wide linear range from 0.1 pg mL−1 to 100 ng mL−1 with a low detection limit of 0.029 pg mL−1. The work presented here can thus offer an atypical approach to size- and morphology-controlled MOFs in electrocatalysis and biosensing.
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