Previous researches on carbon-based solar interfacial evaporation (SIE) have mainly focused on improving the solar absorption, neglecting the effect of water state on the SIE performance. This study proposes an easy strategy by combining carbonization and sulfonation using corncob as the carbon source and concentrated sulfuric acid (HSO) as the sulfonating agent to obtain sulfonated carbonized corncob (SCC) samples. The intermediate water to free water (IW/FW) ratio in the range of 0.53–0.96 within SCC samples has been tailored, which depends on the amount of hydrophilic sulfonic acid groups grafted on SCC. It is found that the amount of hydrophilic sulfonic acid groups and porous structure should be optimal in SCC for high IW/FW ratio. The optimized sample named as SCC-2-4.5 with a high IW/FW ratio of 0.96 and similar surface area to carbonized corncob exhibits the low enthalpy of water evaporation of 1800 J g, achieving the evaporation rate of 3.16 kg m h and evaporation efficiency of 159%. Meanwhile, SCC-2-4.5 realizes an effective separation of Na and Cl, thanks to the electrostatic repulsion caused by its negatively charged sulfonic acid groups. This study provides an effective technique for regulating water state for carbon-based SIE devices on the molecular level.

中文翻译：

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定量调控磺化玉米芯的水态以增强太阳能界面蒸发和抗盐性

以往关于碳基太阳能界面蒸发（SIE）的研究主要集中在提高太阳能吸收上，忽略了水状态对SIE性能的影响。本研究提出了一种简单的策略，以玉米芯为碳源，以浓硫酸（HSO）为磺化剂，将碳化和磺化相结合，获得磺化碳化玉米芯（SCC）样品。 SCC 样品中中间水与游离水 (IW/FW) 的比例在 0.53-0.96 范围内，这取决于 SCC 上接枝的亲水磺酸基团的量。研究发现，对于高 IW/FW 比，SCC 中亲水磺酸基团的数量和多孔结构应该是最佳的。优化后的样品名为SCC-2-4.5，其IW/FW比为0.96，表面积与炭化玉米芯相似，水蒸发焓低至1800 J·g，蒸发速率为3.16 kg·m·h，蒸发效率为159%。同时，SCC-2-4.5利用其带负电的磺酸基团产生的静电斥力实现了Na和Cl的有效分离。这项研究提供了一种在分子水平上调节碳基SIE装置水状态的有效技术。