Advancement in solar still integration with phase change materials-based TES systems and nanofluid for water and wastewater treatment applications

Water crisis has been emerged as major environmental issues at global level, which involves lack of cost-effective and efficient treatment facilities of wastewater and scarcity of drinking water. Commercially available technologies such as RO plants are too expensive to be used in rural areas or remote areas that lack of reliable power supply. Therefore, application of solar energy for water purification such as solar still is gaining much interest due to their efficient utilization for residential and commercial application for the treatment of saline as well as industrial wastewater. Presently, research work for the efficient design with productivity enhancement of the solar still is very much popular and focused area of work. This review article provides the technological advancements in different designs of solar still (active and passive) with the productivity of water. The assessment of thermal energy storage materials and the use of nanofluids for the energy and productivity enhancement for better utilization of solar still are discussed. Another aspect of this review article deals with the utilization of wastewater (industrial and non-portable) in solar still and their treatment applicability. It can be concluded from the present review article that the use of phase change materials and nanomaterials improves the heat transfer rate and productivity of solar still and makes it very effective for industrial use. Graphical abstract