Metal copper mesh with superhydrophobic and superoleophilic surface had been successfully fabricated via a facile solution-immersion process. The hierarchical structure was prepared on the commercial copper mesh surface by etching with the nitric acid. After being modified by 1-hexadecanethiol (HDT), the as-prepared mesh indicated both superhydrophobic and superoleophilic property simultaneously. This as-prepared metal mesh could then be applied for oil and water mixture separation. The unusual wettability of the as-prepared mesh was stable in corrosive conditions, such as acidic, basic, and salt solutions. The solution-immersion method was simple, time-saving, and inexpensive and therefore exhibited great potential application.

Metal nanoparticles are promising catalysts for dye degradation in treating wastewater despite the challenges of recycling and stability. In this study, we have introduced a simple way to prepare Au@polypyrrole (PPy)/Fe3O4 catalysts with Au nanoparticles embedded in a PPy/Fe3O4 capsule shell. The PPy/Fe3O4 capsule shell used as a support was constructed in one-step, which not only dramatically simplified the preparation process, but also easily controlled the magnetic properties of the catalysts through adjusting the dosage of FeCl2·4H2O. The component Au nanoparticles could catalyze the reduction of methylene blue dye with NaBH4 as a reducing agent and the reaction rate constant was calculated through the pseudo-first-order reaction equation. The Fe3O4 nanoparticles permitted quick recycling of the catalysts with a magnet due to their room-temperature superparamagnetic properties; therefore, the catalysts exhibited good reusability. In addition to catalytic activity and reusability, stability is also an important property for catalysts. Because both Au and Fe3O4 nanoparticles were wrapped in the PPy shell, compared with precursor polystyrene/Au composites and bare Fe3O4 nanoparticles, the stability of Au@PPy/Fe3O4 hollow capsules was greatly enhanced. Since the current method is simple and flexible to create recyclable catalysts with high stability, it would promote the practicability of metal nanoparticle catalysts in industrial polluted water treatment.

Yolk-shell composites with a movable Fe(x)O(y) core and mesoporous SiO2 (mSiO2) shell, together with Pd nanoparticles uniformly anchoring on the inner surface, were prepared. The structure and composition of as-prepared catalysts were characterized by scanning electron microscopy, transmission electron microscopy, X-ray diffraction, X-ray photoelectron spectroscopy, Brunauer-Emmett-Teller measurement and Fourier-transform infrared spectroscopy, respectively. They are ideal candidates as nanoreactors for heterogeneous catalysis due to their special structure. The catalytic performance of Fe(x)O(y)/Pd@mSiO2 composites was studied by the reduction of 4-nitrophenol with NaBH4 as a reducing agent. Their reaction rate constant was calculated according to the pseudo-first-order reaction equation. The catalysts could be easily recycled by an external magnetic field due to their superparamagnetic property. Besides good catalytic property, another merit of Fe(x)O(y)/Pd@mSiO2 composites was high stability. We have compared the stability between Fe(x)O(y)/Pd@mSiO2 and Fe3O4@C/Pd composites by ultrasonic treatment and HNO3 solution etching, the stability of the former was much better than the later.

This article reports the facile synthesis of monodisperse polymer hollow spheres by seeded emulsion polymerization without additional treatment. In this method, P(St-MMA-MAA) copolymer latex particles were first prepared by emulsifier-free emulsion polymerization and then used as seeds to carry out emulsion polymerization of methyl methacrylate (MMA), divinyl benzene (DVB), and 2-hydroxyethyl methacrylate (HEMA) with potassium persulfate (KPS) as initiator at 80 degrees C. The void of hollow spheres was readily adjusted by changing the monomer/seed weight ratio, and it could be enlarged while the diameters of hollow spheres changed little after etching by dimethyl formamide (DMF). The effects of synthetic parameters including the monomer composition and the properties of seeds on the morphology of hollow spheres were investigated in detail. On the basis of the experimental results, it seemed reasonable to conclude that the formation of hollow spheres was due to the "dissolution" of seeds in monomers and phase separation between the constituent polymers. As a thermodynamic factor, sodium dodecyl sulfate (SDS) would allow the preparation of solid particles depending on its level.