Hydrothermal carbonization of pine needles (HTC-PN) and their oxidized-activated form HTC-APN are prepared and applied for the adsorption of Malachite Green (MG) in aqueous solution.
Zinc oxide (ZnO) nanoparticles (NPs) were synthesized using the coprecipitation method. The resulting NPs were characterized by X‐ray diffraction, transmission electron microscopy, and Fourier transform infrared spectroscopy. The surface morphology of the coatings has been characterized by scanning electron microscopy (SEM). SEM images show a uniform and homogeneous distribution of ZnO‐NPs in polyurethane (PU) coatings while aggregates appear in epoxy coatings. Using tensile stress–strain test, the effect of the addition of ZnO‐NPs on the mechanical properties of PU and epoxy coatings was examined. The addition of ZnO‐NPs has enhanced the Young's modulus and the tensile strength of PU and epoxy coatings. Through the open‐circuit potential and electrochemical impedance spectroscopy measurements, the anticorrosive properties of PU‐ or epoxy‐coated mild steel panels containing ZnO‐NPs have been investigated in 0.5 M NaCl solution. Nyquist impedance plots for PU and epoxy coatings in PU‐ or epoxy‐coated mild steel panels containing ZnO‐NPs were tested in the absence and presence of ZnO‐NPs have different responses. It has been shown that the dispersion of ZnO‐NPs significantly improves the anticorrosive performance of PU coatings. A PU coating containing 700 mg/kg ZnO‐NPs is recommended to achieve better mechanical properties and corrosion resistance.
ZnO and ZnAl2O4 nanoparticles (NPs) were successfully prepared by the co-precipitation method and characterized by x-ray powder diffraction, transmission electron microscopy, and Fourier transform infrared spectroscopy. The prepared NPs were incorporated into epoxy (EP) coating with mass ratios 200 800 mg/kg of ZnO NPs/EP and ZnAl2O4 NPs /EP. The prepared coatings were characterized by scanning electron microscopy and Fourier transform infrared spectroscopy, and their mechanical properties were investigated, at room temperature, after 5, 10, 15, and 20 days of preparation. Tensile tests showed an improvement in the tensile properties, with the best improvement in ultimate tensile strength (93.2%) for 800 mg/kg ZnAl2O4 NPs/EP coating after 15 days of preparation. The ZnO NPs/EP and ZnAl2O4 NPs/EP coatings exhibited noticeable sensitivity to the stretching rate. Vickers microhardness (Hv) investigations showed normal indentation size effect behavior for all the samples. The best improvement in Hv was attained after 5 days of preparation, for all coatings, with the best improvement (9.15%) for 700 mg/kg ZnO NPs/EP.
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