Sustainable Seawater Desalination and Energy Management: Mechanisms, Strategies, and the Way Forward

Multi-Bioinspired Fog Harvesting Structure with Asymmetric Surface for Hydrogen Revolution

The urgent need for sustainable energy storage drives the fast development of diverse hydrogen production based on clean water resources. Herein, a unique type of multi-bioinspired functional device (MFD) is reported with asymmetric wettability that combines the curvature gradient of cactus spines, the wetting gradient of lotus, and the slippery surface of Nepenthes alata for efficient fog harvesting. The precisely printed MFDs with microscale features, spanning dimensions, and a thin wall are endowed with asymmetric wettability to enable the Janus effects on their surfaces. Fog condenses on the superhydrophobic surface of the MFDs in the form of microdroplets and unidirectionally penetrates its interior due to the Janus effects, and drops onto the designated area with a better fog harvesting rate of 10.64 g cm-2 h-1. Most significantly, the collected clean water can be used for hydrogen production with excellent stability and durability. The findings demonstrate that safe, large-scale, high-performance water splitting and gas separation and collection with fog collection based on MFDs are possible.

Low-Mineral Water Diminishes the Bone Benefits of Boron

This study looked at how desalinated seawater, which has low minerals and high boron, could affect bone health. Prior research suggests that low mineral water may harm bone health and boron could be beneficial, but the overall impact on bone health is still unclear. Eighty-nine-week-old male Balb/C mice were allocated into eight groups and administered either tap water or purified water with varying boron concentrations (0, 5, 40, and 200 mg/L). They were kept in an environment mimicking tropical conditions (35-40 °C, 70-80% humidity) and underwent daily treadmill exercise for 13 weeks. At the 14th week, serum, femora, and lumbar vertebrae were collected for mineral metabolism, bone biomarker, microstructure, and biomechanics evaluation. Boron exposure improved bone formation, microstructure, and biomechanics initially but the benefits weakened with higher levels of exposure (p < 0.05). Co-exposure to purified water elevated serum boron but weakened the promotion of boron on bone minerals and the bone benefits of boron compared to tap water (p < 0.05). Thus, when studying the health effects of boron in desalinated seawater, it is crucial to look at various health effects beyond bone health. Furthermore, it is important to consider the mineral composition of drinking water when using boron for bone health benefits.

Solar-Driven Multistage Device Integrating Dropwise Condensation and Guided Water Transport for Efficient Freshwater and Salt Collection

Interfacial solar vapor generation (ISVG) is an emerging technology to alleviate the global freshwater crisis. However, high-cost, low freshwater collection rate, and salt-blockage issues significantly hinder the practical application of solar-driven desalination devices based on ISVG. Herein, with a low-cost copper plate (CP), nonwoven fabric (NWF), and insulating ethylene-vinyl acetate foam (EVA foam), a multistage device is elaborately fabricated for highly efficient simultaneous freshwater and salt collection. In the designed solar-driven device, a superhydrophobic copper plate (SH-CP) serves as the condensation layer, facilitating rapid mass and heat transfer through dropwise condensation. Moreover, the hydrophilic NWF is designed with rational hydrophobic zones and specific high-salinity solution outlets (Design-NWF) to act as the water evaporation layer and facilitate directional salt collection. As a result, the multistage evaporator with eight stages exhibits a high water collection rate of 2.25 kg m-2 h-1 under 1 sun irradiation. In addition, the desalination device based on the eight-stage evaporator obtains a water collection rate of 13.44 kg m-2 and a salt collection rate of 1.77 kg m-2 per day under natural irradiation. More importantly, it can maintain a steady production for 15 days without obvious performance decay. This bifunctional multistage device provides a feasible and efficient approach for simultaneous desalination and solute collection.