Silicon nitride nanoparticles reinforced the corrosion resistance of Ni-Cu composite coating in simulated seawater solution

Corrosion Resistance of CeO2-GO/Epoxy Nanocomposite Coating in Simulated Seawater and Concrete Pore Solutions

Reinforced concrete structures in the marine environment face serious corrosion risks. Coating protection and adding corrosion inhibitors are the most economical and effective methods. In this study, a nano-composite anti-corrosion filler with a mass ratio of CeO₂:GO = 4:1 was prepared by hydrothermally growing cerium oxide on the surface of graphene oxide. The filler was mixed with pure epoxy resin at a mass fraction of 0.5% to prepare a nano-composite epoxy coating. The basic properties of the prepared coating were evaluated from the aspects of surface hardness, adhesion grade, and anti-corrosion performance on Q235 low carbon steel subjected to simulated seawater and simulated concrete pore solutions. Results showed that after 90 days of service, the corrosion current density of the nanocomposite coating mixed with corrosion inhibitor was the lowest (I_corr = 1.001 × 10^-9 A/cm²), and the protection efficiency was up to 99.92%. This study provides a theoretical foundation for solving the corrosion problem of Q235 low carbon steel in the marine environment.

Efficient oily wastewater treatment by a novel electroflotation-membrane separation system consisting a Ni-Cu-P membrane prepared by electroless nickel plating

Electroflotation-membrane separation system with a conductive membrane has recently emerged as a promising technology for oily wastewater treatment. However, the conductive membrane prepared by electroless plating often suffers the problems of low stability and high activation cost. To solve these problems, this work proposed a new strategy regarding surface metallization of polymeric membrane by surface nickel-catalyzed electroless nickel plating of nickel‑copper‑phosphorus alloys for the first time. It was found that, addition of copper source remarkably enhanced the membranes' hydrophilicity, corrosion resistance and fouling resistance. The Ni-Cu-P membrane had an underwater oil contact angle of up to 140°, and simultaneously possessed rejection rate > 98 % with rather high flux of 65,663.0 L·m^-2·h^-1 and excellent cycling stability when separating n-hexane/water mixtures under gravity drive. The permeability is higher than the state-of-the-art membranes for oil/water separation. The Ni-Cu-P membrane as the cathode can be assembled into an electroflotation-membrane separation system, allowing to separate oil-in-water emulsion with 99 % rejection. Meanwhile, the applied electric field significantly improved membrane flux and fouling resistance (flux recovery up to 91 %) when separate kaolin suspensions. Polarization curve and Nyquist curve analysis further confirmed that addition of Cu element obviously enhanced corrosion resistance of the Ni modified membrane. This work provided a novel strategy to make up high-efficiency membranes for oily wastewater treatment.

Nickel-Catalyzed Sodium Hypophosphite-Participated Direct Hydrophosphonylation of Alkyne toward H-Phosphinates

The traditional methods for the synthesis of phosphinate esters use phosphorus trichloride (PCl₃) as the phosphorous source, resulting in procedures that are often highly polluting and energy intensive. The search for an alternative approach that is both mild and environmentally friendly is a challenging, yet highly rewarding task in modern chemistry. Herein, we use an inorganic phosphorous-containing species, NaH₂PO₂, to serve as the source of phosphorous that participates directly in the nickel-catalyzed selective alkyne hydrophosphonylation reaction. The transformation was achieved in a multicomponent fashion and at room temperature, and most importantly, the H-phosphinate product generated is an advanced intermediate which can be readily converted into diverse phosphinate derivatives, including those bearing new P-C, P-S, P-N, P-Se, and P-O bonds, thus providing a complimentary method to classic phosphinate ester synthesis techniques.