Surfactants exist in atmospheric aerosols mixed with inorganic salts and can significantly influence the formation of cloud droplets due to bulk–surface partitioning and surface tension depression. To model these processes, we need continuous parametrizations of the concentration dependent properties of aqueous surfactant–salt solutions for the full composition range from pure water to pure surfactant or salt. We have developed density functions based on the pseudo-separation method and Young’s mixing rule for apparent partial molal volumes for solutions that mimic atmospheric droplets of marine environments. The developed framework requires only model parameters from binary water–salt and water–surfactant systems and includes the effect of salinity on micellization with composition-dependent functions for the critical micelle concentration (CMC). We evaluate different models and data available in the literature to find the most suitable representations of the apparent partial molal volume of sodium chloride (NaCl) in aqueous solutions and the CMC of selected atmospheric and model surfactants in pure water and aqueous NaCl solutions. We compare model results to experimental density data, available in the literature and obtained from additional measurements, for aqueous solutions containing one of the ionic surfactants sodium octanoate, sodium decanoate, sodium dodecanoate or sodium dodecylsulfate mixed with NaCl in different relative ratios. Our model follows the experimental trends of increasing densities with increasing surfactant concentrations or increasing surfactant–salt mixing ratios both, below and above the CMC, capturing the effect of the inorganic salt on the surfactant micellization.

表面活性剂存在于与无机盐混合的大气气溶胶中，由于体-表面分配和表面张力降低，可以显着影响云滴的形成。为了模拟这些过程，我们需要对从纯水到纯表面活性剂或盐的整个成分范围的表面活性剂盐水溶液的浓度依赖性特性进行连续参数化。我们开发了基于伪分离方法和杨氏混合规则的密度函数，用于模拟海洋环境大气液滴的解决方案的表观部分摩尔体积。开发的框架仅需要来自二元水-盐和水-表面活性剂系统的模型参数，并包括盐度对胶束化的影响以及临界胶束浓度（CMC）的成分依赖性函数。我们评估了文献中可用的不同模型和数据，以找到水溶液中氯化钠 (NaCl) 的表观偏摩尔体积以及纯水和 NaCl 水溶液中选定的大气和模型表面活性剂的 CMC 的最合适表示。我们将模型结果与实验密度数据进行比较，实验密度数据可在文献中获得，并通过额外测量获得，对于含有离子表面活性剂辛酸钠、癸酸钠、十二酸钠或十二烷基硫酸钠之一与 NaCl 以不同相对比例混合的水溶液。我们的模型遵循随着表面活性剂浓度的增加或表面活性剂-盐混合比的增加（低于和高于CMC）而增加密度的实验趋势，捕捉无机盐对表面活性剂胶束化的影响。