基于不同类型溶液蒸气压特性的太阳能界面蒸发实验研究

太阳能界面蒸发可实现高效太阳能海水淡化和蒸发式污水处理，但目前的研究大多局限于纯水或NaCl溶液。实际脱盐或废水处理中溶质会与此不同，导致溶液蒸气压变化并影响蒸发性能。本文首先分析了溶液表面蒸气压曲线类型，将其分为上凸型、下凹型和直线型。针对这几种蒸气压曲线进一步选取[EMIM][OTf]、[EMIM][Ac]和NaCl水溶液作为代表溶液，在不同辐照强度和浓度下进行了实验研究，并与纯水的蒸发作对比。实验结果表明：低浓度下[EMIM][OTf]水溶液展现出了良好的蒸发性能， 主要原因是由于其蒸气压处于上凸区间；当溶液浓度升高或辐照强度提升时，[EMIM][OTf]溶液的蒸发速率提升较NaCl水溶液小，主要原因在于蒸发过程的浓度极化导致气液界面处的[EMIM][OTf]浓度升高，蒸气压相差较小；不同工况下[EMIM][Ac]水溶液的蒸发速率均较慢，纯水的蒸发速率最快，体现了蒸气压对蒸发性能的关键影响，原因是低蒸气压导致高蒸发温度，并带来更多的能量损失。

Experimental study on solar interfacial evaporation based on vapor pressure characteristics of different solutions

Solar interface evaporation can achieve high-efficiency solar desalination and evaporative sewage treatment, but most of the current research is limited to pure water or NaCl solution. The actual solute in desalination and wastewater treatment will be different, which will lead to different vapor liquid equivalent behavior of the solution and affect the evaporation performance, but the research in this area is lack. This work analyzes different vapor pressure curves of the solution with different concentration, and divides them into three types: convex type, concave type and straight type,and further selects [EMIM][OTf]/H₂O, [EMIM][Ac]/H₂O and NaCl/H₂O as representative solutions. Experiments were conducted under different irradiation intensities and concentrations, and the evaporation of pure water was compared. The experimental results show that [EMIM][OTf]/H₂O exhibits good evaporation performance under low concentration, the main reason is that its vapor pressure is in the convex region; when the concentration of the solution increases or when the irradiation intensity increases, the evaporation rate of the [EMIM][OTf]/H₂O is lower than that of the NaCl/H₂O, the reason is that the concentration polarization of the evaporation process causes the concentration of [EMIM][OTf]/ H₂O at the gas-liquid interface to increase, and the difference in vapor pressure is small; the evaporation rate of [EMIM][Ac]/H₂O is the lowest under different working condition, while the evaporation rate of pure water is the highest, which reflects the key influence of vapor pressure on evaporation performance, because low vapor pressure leads to high evaporation temperature and more energy loss.