The sonochemical effects of ultrasound (US) treatment on 14 flavonoids representing the main flavonoids in citrus fruit were investigated in a standard mixture by stability evaluation of a model system. Degradation products were further tentatively identified by Fourier transform infrared spectroscopy and high-performance liquid chromatography–ultraviolet detection–electrospray ionization tandem mass spectrometry. Thirteen flavonoids (i.e., eriocitrin, narirutin, neohesperidin, quercitrin, eridictyol, didymin, naringenin, luteolin, sinensetin, nobiletin, tangeretin, naringin, and hesperidin) were fairly stable whereas quercetin was degraded significantly by US treatment. The types of solvent and temperature used were important factors that determined the resulting degradation reactions. The degradation rate of quercetin was highest in 80% ethanol aqueous solution and decreased with increasing temperature. Longer US durations caused increases in the extent of quercetin degradation. Liquid height, ultrasonic intensity, pulse length, and duty cycle of US affected degradation rates but did not change the nature of degradation of the flavonoids. Four types of reactions occurred simultaneously for quercetin under US treatment: oxidation, addition, polymerization, and decomposition. Eight degradation products were tentatively identified as dimer, alcohol addition, oxidation, and decomposition products.

Marine fouling organisms have caused inconvenience to humans for a long time owing to their high vitality and great destructiveness. Self-polishing antifouling coatings are considered to be among the most effective antifouling technologies. In this study, zinc-based acrylate copolymers (ZnPs) were designed and synthesized using a bifunctional zinc acrylate monomer (ZnM) as a new self-polishing monomer, and three acrylate monomers (namely, methyl methacrylate, ethyl acrylate and 2-methoxyethyl acrylate)were used as comonomers. ZnPs that contained the new ZnM were characterized by Fourier transform infrared spectroscopy, proton nuclear magnetic resonance spectroscopy and gel permeation chromatography. Different antifouling coatings were prepared using the previously mentioned ZnPs as the matrix material, and their erosion properties were investigated using a lab rotor test. A field test of the prepared coatings at various geographical locations showed their excellent antifouling performance as they inhibited the settlement of barnacles in both the South China Sea for 9 months and in the Yellow Sea for at least 15 months. The results of this study highlight that the biocidal ZnP-based coatings are highly promising candidates for marine antifouling applications.

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The designed sample is prepared by self-assembly of octadecyltrichlorosilane and deposition of ferric stearate, and the contact angle is 160°.

Phosphate and amide functionalized magnetic nanocomposites were successfully prepared via in situ synthesis for the extraction of uranium from seawater combined with an antifouling property.

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Developing noble-metal-free electrocatalysts with high efficiency and low cost in the all-pH range is highly desired but challenging. Herein, we constructed the hybrid interface structure of NiSe2 and Ni nanoparticles and embedded them into an N,S-codoped carbon nanosheet framework (NiSe2/Ni-NSC). The partial selenization treatment endows the catalyst with an abundant interface, resulting in optimal electronic structure and hydrogen adsorption energy due to the strong interaction between Ni metal and metallic NiSe2. The ultrafine nanoparticle size allows the active edge sites to be fully exposed and their utilization efficiency to be improved. Benefiting from the structure characteristics, interface engineering, and high electroconductivity, the NiSe2/Ni-NSC exhibits superior and stable hydrogen evolution performances in pH-universal media, especially in acidic solution with an overpotential as low as 53 mV to achieve 10 mA cm–2 current density, compared favorably with most Pt-free catalysts. Our work may pave a novel pathway to design heterostructure catalysts with high performance toward hydrogen evolution in the all-pH range.

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