Title: Exploiting the aluminum nitride bandgap for water separation and light-enhanced evaporation
The aluminum nitride bandgap energy matches the binding energy between salt and water molecules. Here we study the effect of 405-nm light on the rates of evaporation when saline solutions are im-bibed within a porous ceramic aluminum nitride wick. Sensitive measurements are taken in a self-referencing setup and compared with the capillary fluid response. Evaporation rates increase with light illumination when the solution is more saline in a manner that indicates interfacial charge-transfer characteristics. Our results show consistent trends and strong potential for photonic environmental applications in salt-water separation more »« less
Leung, James; Feng, Ji; Vuong, Luat T.
(, EPJ Web of Conferences)
Kibler, B.; Millot, G.; Segonds, P.
(Ed.)
Aluminum nitride is a white, hydrophilic, high-band-gap ceramic. Here we report on the light-induced evaporation of saltwater through a capillary wick composed of drop-cast microparticles. Saltwater evaporation rates are significantly higher than expected. Our results point to significant potential for this interface-driven approach in solar non-thermal desalination and water separation technologies.
Abstract The interactions between the atmosphere, ocean, and beach in the swash zone are dynamic, influencing water flux and solute exchange across the land‐sea interface. This study employs groundwater simulations to examine the combined effects of waves and evaporation on subsurface flow and salinity dynamics in a shallow beach environment. Our simulations reveal that wave motion generates a saline plume beneath the swash zone, where evaporation induces hypersalinity near the sand surface. This leads to the formation of a hypersaline plume beneath the swash zone during periods of wave recession, which extends vertically downward to a maximum depth of 30 cm, driven by the resulting vertical density gradients. This hypersaline plume moves approximately 2 m landward to the top of the swash zone and down the beachface due to wave‐induced seawater infiltration and is subsequently diluted by the surrounding saline groundwater. Furthermore, swash motion increases near‐surface moisture, leading to an elevated evaporation rate, with dynamic fluctuations in both moisture and evaporation rate due to high‐frequency surface inundation caused by individual waves. Notably, the highest evaporation rates on the swash zone surface do not always correspond to the greatest elevations of salt concentration within the swash zone. This is because optimal moisture is also required—neither too low to impede evaporation nor too high to dilute accumulated salt near the surface. These insights are crucial for enhancing our understanding of coastal groundwater flow, biogeochemical conditions, and the subsequent nutrient cycling and contaminant transport in coastal zones.
The interactions between the atmosphere, ocean, and beach in the swash zone are dynamic, influencing water flux and solute exchange across the land-sea interface. However, the integrated role of these interactions in governing transport processes within the swash zone remains unexplored. This study employs groundwater simulations to examine the combined effects of waves and evaporation on subsurface flow and salinity dynamics in a shallow beach environment. Our simulations reveal that wave motion generates a saline plume beneath the swash zone, where evaporation induces hypersalinity near the sand surface. This leads to the formation of a hypersaline plume beneath the swash zone during periods of wave recession, which extends vertically downward, driven by the resulting vertical density gradients. This hypersaline plume moves landward and down the beachface due to wave-induced seawater infiltration and is subsequently diluted by the surrounding saline groundwater. Furthermore, swash motion increases near-surface moisture, leading to an elevated evaporation rate, with dynamic fluctuations in both moisture and evaporation rate due to high-frequency surface inundation caused by individual waves. Notably, the highest evaporation rates on the swash zone surface do not always correspond to the greatest elevations of salt concentration within the swash zone. This is because optimal moisture is also required – neither too low to impede evaporation nor too high to dilute accumulated salt near the surface. These insights are crucial for enhancing our understanding of coastal groundwater flow, biogeochemical conditions, and the subsequent nutrient cycling and contaminant transport in coastal zones.
Chen, Xi; He, Shuaiming; Falinski, Mark M.; Wang, Yuxi; Li, Tian; Zheng, Sunxiang; Sun, Dongya; Dai, Jiaqi; Bian, Yanhong; Zhu, Xiaobo; et al
(, Energy & Environmental Science)
Solar-thermal evaporation is a promising technology for energy-efficient desalination, but salt accumulation on solar absorbers and system longevity are the major challenges that hinder its widespread application. In this study, we present a sustainable Janus wood evaporator that overcomes these challenges and achieves a record-high evaporation efficiencies in hypersaline water, one of the most difficult water sources to treat via desalination. The Janus wood evaporator has asymmetric surface wettability, where the top layer acts as a hydrophobic solar absorber with water blockage and salt resistance, while the bottom hydrophilic wood layer allows for rapid water replenishment and superior thermal insulation. An evaporation efficiency of 82.0% is achieved for 20% NaCl solution under 1 sun, and persistent salt-resistance is observed during a 10-cycle long-term test. To ensure the environmental impact of the Janus wood evaporator, for the first time, a life cycle assessment (LCA) is conducted to compare this Janus wood evaporator with the emerging Janus evaporators, indicating a functional and more sustainable opportunity for off-grid desalination and humanitarian efforts.
Zhao, Mengdi; Kusolthossakul, Woraprach; Fang, Kejie
(, OSA Continuum)
Integrated nonlinear photonic circuits received rapid development in recent years, providing all-optical functionalities enabled by cavity-enhanced photon-photon interaction for classical and quantum applications. A high-efficiency fiber-to-chip interface is key to these integrated photonic circuits for quantum information tasks, as photon-loss is a major source that weakens quantum protocols. Here, overcoming material and fabrication limitation of thin-film aluminum nitride by adopting a stepwise waveguiding scheme, we demonstrate low-loss adiabatic fiber-optic couplers in aluminum nitride films with a substantial thickness (∼600 nm) for optimized nonlinear photon interaction. For telecom (1550 nm) and near-visible (780 nm) transverse magnetic-polarized light, the measured insertion loss of the fiber-optic coupler is -0.97 dB and -2.6 dB, respectively. Our results will facilitate the use of aluminum nitride integrated photonic circuits as efficient quantum resources for generation of entangled photons and squeezed light on microchips.
Singh, Navindra D., Leung, James, and Vuong, Luat. Exploiting the aluminum nitride bandgap for water separation and light-enhanced evaporation. Retrieved from https://par.nsf.gov/biblio/10474406. EPJ Web of Conferences 287. Web. doi:10.1051/epjconf/202328709014.
Singh, Navindra D., Leung, James, & Vuong, Luat. Exploiting the aluminum nitride bandgap for water separation and light-enhanced evaporation. EPJ Web of Conferences, 287 (). Retrieved from https://par.nsf.gov/biblio/10474406. https://doi.org/10.1051/epjconf/202328709014
Singh, Navindra D., Leung, James, and Vuong, Luat.
"Exploiting the aluminum nitride bandgap for water separation and light-enhanced evaporation". EPJ Web of Conferences 287 (). Country unknown/Code not available: European Optical Society Annual Meeting. https://doi.org/10.1051/epjconf/202328709014.https://par.nsf.gov/biblio/10474406.
@article{osti_10474406,
place = {Country unknown/Code not available},
title = {Exploiting the aluminum nitride bandgap for water separation and light-enhanced evaporation},
url = {https://par.nsf.gov/biblio/10474406},
DOI = {10.1051/epjconf/202328709014},
abstractNote = {The aluminum nitride bandgap energy matches the binding energy between salt and water molecules. Here we study the effect of 405-nm light on the rates of evaporation when saline solutions are im-bibed within a porous ceramic aluminum nitride wick. Sensitive measurements are taken in a self-referencing setup and compared with the capillary fluid response. Evaporation rates increase with light illumination when the solution is more saline in a manner that indicates interfacial charge-transfer characteristics. Our results show consistent trends and strong potential for photonic environmental applications in salt-water separation},
journal = {EPJ Web of Conferences},
volume = {287},
publisher = {European Optical Society Annual Meeting},
author = {Singh, Navindra D. and Leung, James and Vuong, Luat},
editor = {Kibler, B. and Millot, G. and Segonds, P.}
}
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