Controlled Synthesis of Perforated Oxide Nanosheets with High Density Nanopores Showing Superior Water Purification Performance

Abstract

A method for creating genuine nanopores in high area density on monolayer two-dimensional (2D) metallic oxides has been developed. By use of the strong reduction capability of hydroiodic acid, active metal ions, such as FeIII and CoIII, in 2D oxide nanosheets can be reduced to a divalent charge state (2+). The selective removal of FeO2 and CoO2 metal oxide units from the framework can be tuned to produce pores in a range of 1–4 nm. By monitoring of the redox reaction kinetics, the pore area density can be also tuned from ∼0.9 × 104 to ∼3.3 × 105 μm–2. The universality of this method to produce much smaller pores and higher area density than the previously reported ones has been proven in different oxide nanosheets. To demonstrate their potential applications, ultrasmall metal organic framework particles were grown inside the pores of perforated titania oxide nanosheets. The optimized hybrid film showed ∼100% rejection of methylene blue (MB) from the water. Its water permeance reached 4260 L m–2 h–1 bar–1, which is 1–3 orders of that for reported 2D membranes with good MB rejections.

An Introduction to Nanopore Sequencing: Past, Present, and Future Considerations

“…While nanopores have been applied to numerous different areas of focus, including water purification [75], protein identification and characterization [31,76] and recently data storage [77] -we will focus on nucleic acid sequencing for the applications section of our review, though other reviews explore the wide field of nanopore technologies beyond this scope [78].…”

Molecular-Level Insights into Unique Behavior of Water Molecules Confined in the Heterojunction between One- and Two-Dimensional Nanochannels

“…In the past decades, nanoconfined water has always received intensive attention since it plays a significant role in many applications such as drug delivery, DNA sequencing and therapeutic, , nanofluidic, water purification, , and energy storage in supercapacitors and batteries. , Compared to the bulk water, nanoconfinement with different shapes and dimensions can lead to anomalous changes in the structures, dynamics, and other physical properties of water, such as distinct ice phase, , enhancement of the diffusion rate and different modes of diffusion, − and the transformation of the hydrogen bond (HB) network. ,, In spite of great progress in experimental characterizations, it still has to fight against enormous challenges for experimental observations to provide a comprehensive understanding of the unique properties of nanoconfined water. ,− As a powerful complementary analysis tool, theoretical simulations, especially molecular dynamics (MD), can offer a molecular-level insight into the structures and dynamics of water confined in multi-dimensional nanoscale environment. − …”

“…In the past decades, nanoconfined water has always received intensive attention since it plays a significant role in many applications such as drug delivery, 1 DNA sequencing and therapeutic, 2,3 nanofluidic, 4 water purification, 5,6 and energy storage in supercapacitors and batteries. 7,8 Compared to the bulk water, nanoconfinement with different shapes and dimensions can lead to anomalous changes in the structures, dynamics, and other physical properties of water, such as distinct ice phase, 9,10 enhancement of the diffusion rate and different modes of diffusion, 11−16 and the transformation of the hydrogen bond (HB) network.…”

“…Sahimi and coworkers 41 further verified that weakened HBs should be responsible for the depression of the freezing by comparing the formation of HB networks in CNT and silicon-based nanotube. Besides the structures in 1-D nanoconfinement, the milestone MD work of Hummer et al 31 revealed that single-file water chain in (6,6) CNT has a pulselike diffusion pattern via bursts of their HB network (denoted as the singlefile diffusion) and yield an extraordinary flow speed of around 51 × 10 −14 cm 3 s −1 . A longer simulation of water molecules in the CNT ring proposed by Mukherjee et al 32 showed that water molecules can escape from the smaller chain and join the longer one.…”

A pairwise/sandwich-like assembly consisting of a TaO3 nanomesh and reduced graphene oxide for a pelletized self-supported cathode towards high-areal-capacity Li–S batteries

“…Thus, signicant efforts have been devoted to drilling of 2D nanosheets, namely the articial fabrication of inplane pores by chemical/thermal etching and templating methods. [21][22][23][24] However, in general, such pores are not uniform in size, shape and arrangement, disabling the transportation of a specic ion and blocking others by so-called size-sieving effects. In contrast, an intrinsic crystalline nanomesh structure is expected to be more efficient and attractive because it provides ion-permeable channels with well-dened sizes and shapes.…”