In this contribution, we synthesized water-soluble Fe(3)O(4) nanoparticles (NPs) with sufficiently high solubility (28 mg mL(-1)) and stability (at least one month) through a hydrothermal approach, and found that they exhibited excellent removal ability for heavy-metal ions from waste water. For the first time, the water-soluble Fe(3)O(4) NPs were used as adsorbents for heavy-metals removal from wastewater. It is noteworthy that the adsorption ability of the water-soluble Fe(3)O(4) NPs for Pb(2+) and Cr(6+) is stronger than water-insoluble Fe(3)O(4) NPs. Furthermore, the water-soluble Fe(3)O(4) NPs exhibited relatively high saturation magnetization (83.4 emu g(-1)), which allowed their highly-efficient magnetic separation from wastewater. The most important thing is that the water-soluble magnetite as an adsorbent can directly dissolve in water without the help of mechanical stirring or any extraneous forces, which may solve a key problem for the practical application of magnetic powders in the field of sewage purification. Moreover, the water-soluble Fe(3)O(4) NPs show a highly-efficient adsorption capacity for 10 ppm of Pb(2+) ions solution which can reach 90% within 2 minutes.
Droplet
deposition on superhydrophobic surfaces has been a great challenge
owing to the shortness of the impact contact time. Despite recent
research progress regarding flat superhydrophobic surfaces, improving
deposition on ubiquitous wired and curved superhydrophobic leaves
remains challenging as their surface structures promote asymmetric
impacts, thereby shortening the contact times and increasing the likelihood
of droplet splitting. Here, we propose a strategy to solve the deposition
problems based on an analysis of the impact dynamics and a rational
selection of additives. Combining the prominent extension property
of flexible polymers with surface tension reduction of the surfactant,
the well-chosen binary additives cooperatively solve retention and
coverage problems by limiting the fragment and enhancing local pinning
and wetting processes at a very low usage. This work advances the
understanding of droplet deposition by rationally selecting additives
based on the impact dynamics, which is believed to be useful in a
variety of spraying, coating, and printing applications.
Both structural and compositional modulations are important for high-performance electrode materials in energy conversion/storage devices. Here hierarchical-structure nitrogen-rich hybrid porous carbon capsules with bamboo-like carbon nanotube whiskers (N-CC@CNTs) grown in situ have been specifically designed, which combine the advantageous features of high surface area, abundant active sites, easy access to medium and favorable mass transport. As a result, the newly prepared N-CC@CNTs show highly efficient catalytic activity in oxygen reduction reaction in alkaline media for fuel cells, which not only outperforms commercial Pt-based catalysts in terms of kinetic limiting current, stability and tolerance to methanol crossover effect, but is also better than most of the nanostructured carbon-based catalysts reported previously. On the other hand, as an anode material for lithium ion batteries, the N-CC@CNTs obtained also exhibit an excellent reversible capacity of ca. 1337 mA h g(-1) at 0.5 A g(-1), outstanding rate capability and long cycling stability, even at a current density of 20 A g(-1). The capacity is the highest among all the heteroatom-doped carbon materials reported so far, and is even higher than that of many of the composites of metal, metal oxides or metal sulfides with carbon materials.
The promising complex structures of graphene nanocapsules with in-situ formed graphene sheets (GC-Gs) have been generated by partially peeling the multiwalled graphene capsules (MWGCs) with a small size of ca. 15 nm. The abundant edges and defects on the in-situ induced graphene sheets and capsule walls largely favored the lithiation/de-lithiation reaction and resulted in a high Li-ion storage level. Since the surface area loss of GC-Gs during stacking and aggregation is generally avoided due to the branched structures and the active doping atoms (N, S) can be intercalated into the carbon lattices during sample preparation, the unique GC-Gs possess an excellent reversible capacity of 1373 mAh g −1 at 0.5 A g −1 as anode material in lithium-ion batteries. This value is more than three times that of the theoretical capacity of state-of-the-art graphite counterpart, and higher than those of most carbon materials reported to date and even the composites of metal, alloys with carbon materials.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.