Solar-driven desalination has emerged as a promising approach to address water scarcity caused by the decreasing supply of freshwater. Reducing the enthalpy of water vaporization is crucial for enhancing the efficiency of solar-powered desalination. In this study, inspired by the Hofmeister effect, we developed a highly hydratable network hydrogel evaporator to achieve a superior evaporation rate in brine compared with pure water. The evaporator comprised a carbonized layer as the photothermal layer and a chitosan aerogel hydrogel as the hydratable matrix. The hydrogel exhibited a dramatically reduced vaporization enthalpy of 1397 J/g and a significant evaporation rate of 2.38 kg m⁻² h⁻¹ when exposed to seawater. These results demonstrated the superior performance of hydrogel compared with pure water (1.91 kg m⁻² h⁻¹). Excellent evaporation rates and outstanding salt resistance ensured efficient coordination for practical long-term desalination applications. Further investigations revealed that the remarkable evaporation performance of the carbonized chitosan (CCS) hydrogel in brine environments was attributed to its hydrability, which was regulated by Cl⁻. According to the Hofmeister effect, Cl⁻ accelerated the hydration chemistry in CCS and suppressed the associated crystallinity, which resulted in a lower enthalpy of vaporisation owing to a higher amount of intermediate water. With its superior evaporation performance in brine and comprehensive theoretical simulation analysis, this study presents an achievable and economical strategy for simultaneously addressing the water and energy crises.

中文翻译：

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霍夫迈斯特效应诱导水凝胶水活化及其在盐水中加速太阳蒸发的应用


太阳能驱动的海水淡化已成为解决淡水供应减少造成的水资源短缺的一种有前途的方法。降低水汽化焓对于提高太阳能海水淡化的效率至关重要。在这项研究中，受霍夫迈斯特效应的启发，我们开发了一种高度可水合的网络水凝胶蒸发器，与纯水相比，它在盐水中实现了更高的蒸发速率。蒸发器由作为光热层的碳化层和作为可水合基质的壳聚糖气凝胶水凝胶组成。当暴露于海水中时，水凝胶表现出 1397 J/g 的显着蒸发焓和 2.38 kg ^{m-2 h-1} 的显着蒸发速率。这些结果表明，与纯水 （1.91 kg ^{m-2 h-1}） 相比，水凝胶的性能更优越。出色的蒸发速率和出色的耐盐性确保了实际长期海水淡化应用的有效协调。进一步的研究表明，碳化壳聚糖 （CCS） 水凝胶在盐水环境中的显着蒸发性能归因于其水合性，而水合性受 Cl⁻ 调节。根据霍夫迈斯特效应，Cl⁻ 加速了 CCS 中的水合化学反应并抑制了相关的结晶度，由于中间水的含量较高，导致汽化焓较低。凭借其在盐水中卓越的蒸发性能和全面的理论模拟分析，本研究提出了一种同时解决水和能源危机的可实现且经济的策略。