Enhanced Water Evaporation from Å-Scale Graphene Nanopores

Lee, Wan-Chi; Ronghe, Anshaj; Villalobos, Luis Francisco; Huang, Shiqi; Dakhchoune, Mostapha; Mensi, Mounir; Hsü, Kenneth J.; Ayappa, K. G.; Agrawal, Kumar Varoon

doi:10.1021/acsnano.2c07193

Cited by 20 publications

(57 citation statements)

References 85 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Following the simulation, all organic molecules are found to be confined to the water box. Water evaporation is found to occur with a rate of 0.24 molecules nm –1 ns –1 which is higher than previous studies . Nonetheless, evaporation does not significantly change the dimension of the system during the simulation time.…”

Section: Resultsmentioning

confidence: 99%

See 1 more Smart Citation

A Molecular Dynamic Study of the Effects of Surface Partitioning on the OH Radical Interactions with Solutes in Multicomponent Aqueous Aerosols

Masaya

Goulay

2023

J. Phys. Chem. A

View full text Add to dashboard Cite

The surface−bulk partitioning of small saccharide and amide molecules in aqueous droplets was investigated using molecular dynamics. The air−particle interface was modeled using a 80 Å cubic water box containing a series of organic molecules and surrounded by gaseous OH radicals. The properties of the organic solutes within the interface and the water bulk were examined at a molecular level using density profiles and radial pair distribution functions. Molecules containing only polar functional groups such as urea and glucose are found predominantly in the water bulk, forming an exclusion layer near the water surface. Substitution of a single polar group by an alkyl group in sugars and amides leads to the migration of the molecule toward the interface. Within the first 2 nm from the water surface, surface-active solutes lose their rotational freedom and adopt a preferred orientation with the alkyl group pointing toward the surface. The different packing within the interface leads to different solvation shell structures and enhanced interaction between the organic molecules and absorbed OH radicals. The simulations provide quantitative information about the dimension, composition, and organization of the air−water interface as well as about the nonreactive interaction of the OH radicals with the organic solutes. It suggests that increased concentrations, preferred orientations, and decreased solvation near the air−water surface may lead to differences in reactivities between surface-active and surface-inactive molecules. The results are important to explain how heterogeneous oxidation mechanisms and kinetics within interfaces may differ from those of the bulk.

show abstract

Section: Resultsmentioning

confidence: 99%

“…Water evaporation is found to occur with a rate of 0.24 molecules nm −1 ns −1 which is higher than previous studies. 168 Nonetheless, evaporation does not significantly change the dimension of the system during the simulation time. The air−water interface is defined to extend 10 Å into the water box and 10 Å into the gas phase.…”

Section: Resultsmentioning

confidence: 99%

A Molecular Dynamic Study of the Effects of Surface Partitioning on the OH Radical Interactions with Solutes in Multicomponent Aqueous Aerosols

Masaya

Goulay

2023

J. Phys. Chem. A

View full text Add to dashboard Cite

show abstract

“…This study provided valuable insights into the mechanism and energetics of evaporation for pure water. A recent study 34 investigated the evaporation of water through angstrom-scale nanopores placed at the liquid−vapor interface and found many-fold increase in the rate of evaporation. However, there have been very few studies on the molecularlevel mechanism and kinetics of water evaporation from free surfaces of concentrated aqueous ionic solutions.…”

Section: Introductionmentioning

confidence: 99%

Mechanism, Kinetics, and Potential of Mean Force of Evaporation of Water from Aqueous Sodium Chloride Solutions of Varying Concentrations

Pandey

Chandra

2023

J. Phys. Chem. B

View full text Add to dashboard Cite

The mechanism, kinetics, and potential of mean force of evaporation of water from aqueous NaCl solutions are investigated through both unbiased molecular dynamics simulations and also biased simulations using the umbrella sampling method. The results are obtained for aqueous solutions of three different NaCl concentrations ranging from 0.6 to 6.0 m and also for pure water. The rate of evaporation is found to decrease in the presence of ions. It is found that the process of evaporation of a surface water molecule from ionic solutions can be triggered through its collision with another water or chloride ion. Such collisions provide the additional kinetic energy that is required for evaporation. However, when the collision takes place with a Cl − ion, the evaporation of the escaping water also involves a collision with water in the vicinity of the ion at the same time along with the ion−water collision. These two collisions together provide the required kinetic energy for escape of the evaporating water molecule. Thus, the mechanism of evaporation process of ionic solutions can be more complex than that of pure water. The potential of mean force (PMF) of evaporation is found to be positive and it increases with increasing ion concentration. Also, no barrier in the PMF is found to be present for the condensation of water from vapor phase to the surfaces of the solutions. A detailed analysis of the unsuccessful evaporation attempts by surface water molecules is also made in the current study.

show abstract

“…Molecular dynamics (MD) simulations reveal that the evaporation from a liquid–vapor interface is facilitated by the rapid translational and rotational dynamics of interfacial water, induced by fewer hydrogen bonds (HBs) at the interface compared with bulk water. − Several strategies have been developed to achieve enhanced evaporation by disrupting interactions between the interfacial water molecules. − Enhanced water evaporation has been reported for nanochannels where evaporation occurs through a slit or an extended air–water interface at the nanochannel edge . In a distinct departure from these pore topologies, we have recently studied water evaporation from two-dimensional nanopores whose dimensions are comparable to the size of a water molecule . This topology, realized for graphene sheets hosting two-dimensional functionalized nanopores, exhibited a 10–30 fold enhancement in evaporation flux relative to the bare liquid–vapor interface.…”

Section: Introductionmentioning

confidence: 99%

“…This topology, realized for graphene sheets hosting two-dimensional functionalized nanopores, exhibited a 10–30 fold enhancement in evaporation flux relative to the bare liquid–vapor interface. MD simulations revealed a rapid disruption of water–water HBs in the vicinity of functionalized nanopores, resulting in the increased evaporation tendency of water molecules . In addition to the graphene nanopore-based systems, several 2D materials based on covalent organic frameworks (COFs) and metal organic frameworks (MOFs) are also promising candidates for separation processes due to increased flexibility in process synthesis to control pore size, chemistry, and pore density. − …”

Section: Introductionmentioning

confidence: 99%

Graphene Nanopores Enhance Water Evaporation from Salt Solutions: Exploring the Effects of Ions and Concentration

Ronghe

Ayappa

2023

Langmuir

Self Cite

View full text Add to dashboard Cite

With increased water stress, the development of clean water technologies is an active area of research. Evaporation-based solutions offer the advantage of low energy consumption, and recently a 10−30 fold enhancement in water evaporation flux has been observed through Å-scale graphene nanopores (Lee, W.-C., et al., ACS Nano 2022, 16(9), 15382). Herein, using molecular dynamics simulations, we examine the suitability of Å-scale graphene nanopores in enhancing water evaporation from salt solutions (LiCl, NaCl, and KCl). Cation−π interactions between ions and the surface of nanoporous graphene are found to significantly influence ion populations in the nanopore vicinity, leading to varied water evaporation fluxes from different salt solutions. The highest water evaporation flux was observed for KCl solutions, followed by NaCl and LiCl solutions, with the differences reducing at lower concentrations. Relative to the bare liquid−vapor interface, 4.54 Å nanopores exhibit the highest evaporation flux enhancements ranging from 7 to 11, with an enhancement of 10.8 obtained for 0.6 M NaCl solution, which closely resembles seawater compositions. Functionalized nanopores induce short-lived water−water hydrogen bonds and reduce surface tension at the liquid−vapor interface, thereby lowering the free energy barrier for water evaporation with a negligible effect on the ion hydration dynamics. These findings can aid in developing green technologies for desalination and separation processes with low thermal energy input.

show abstract

Enhanced Water Evaporation from Å-Scale Graphene Nanopores

Cited by 20 publications

References 85 publications

A Molecular Dynamic Study of the Effects of Surface Partitioning on the OH Radical Interactions with Solutes in Multicomponent Aqueous Aerosols

A Molecular Dynamic Study of the Effects of Surface Partitioning on the OH Radical Interactions with Solutes in Multicomponent Aqueous Aerosols

Mechanism, Kinetics, and Potential of Mean Force of Evaporation of Water from Aqueous Sodium Chloride Solutions of Varying Concentrations

Graphene Nanopores Enhance Water Evaporation from Salt Solutions: Exploring the Effects of Ions and Concentration

Contact Info

Product

Resources

About