Water has a constant evaporation rate that depends on its mass and the subjected heat. However, the evaporation rate can be enhanced as some recent studies clarified by adding tiny percentage of nano materials. These materials increases the thermal storage inside the water and increase its heat absorption resulting in higher evaporation rates.
The evaporation rate surely depends on the amount of heat available to evaporate it. If you add anything to it you will usually find the additive evaporates first, then the water. This is exactly NOT what you want a solar still to do! All non-volatile additives must slow evaporation loss, not increase it, otherwise you break the law of conservation of energy (you would be evaporating water with less than 570 calories per gram)
Water has a constant evaporation rate that depends on its mass and the subjected heat. However, the evaporation rate can be enhanced as some recent studies clarified by adding tiny percentage of nano materials. These materials increases the thermal storage inside the water and increase its heat absorption resulting in higher evaporation rates.
I totally agree with the previous answers and I would like to add that various attempts were made to enhance the productivity of the solar still by introducing Phase Change Materials (PCMs), also called latent heat storage materials in the still basin. Black granite gravels, sponge pieces, plastic balls filled with salt, and steel fins are a commonly used storage materials with single basin solar stills.
There are many articles related to this topic available in Research Gate, so I advise you to research by ‘’Publications’’ and I hope you will find an answer to your question.