Enhancing the evaporation rate at the air-water interface with use of conductive nanoparticles and superhydrophobic coated gauze for improved desalination process

Abstract

Most living organisms require fresh water to survive, and our planet is composed of 70% of water. Unfortunately, most of it is salt water and not fresh water, and very soon the fresh water will be depleted. The solution to this problem is desalination using the evaporation method. Evaporation is a natural phenomenon and plays a significant role in nature. Most of the evaporation process involves a total temperature increase of an entire body of water. However, recent research in nanotechnology can help in selective heating of the air-water interface. The nanofluid that forms the colloidal mixture of nanoparticles is dispersed in a fluid medium that possesses thermophysical properties and plays a significant role in heat transfer. In this research, nanofluids were prepared by dispersing carbon black (CB) and graphene nanoparticles in tap water, salt water, and deionized (DI) water. The concentration of nanoparticles in a water varying, where a 0.1% concentration of nanoparticles in a fluid gave better results than nanoparticle concentrations of 0.05% or 0.5%. Furthermore, the combination of nanoparticles with fluid increases its evaporation rate by 11.20% for tap water, 14.22% for salt water, and 9.07% for DI water. However, when nanoparticles were combined with a rubber black base, the evaporation rate increased to 17.98% for tap water, 18.78% for salt water, and 16.05% for DI water. In all tests, the addition of carbon black showed better results compared to other nanoparticles. In the next stage of this research, nanoparticles, i.e., carbon black, graphene, and carbon nanotubes (CNTs), were coated on a cotton gauze along with a superhydrophobic liquid, which makes the coated gauze float on water and locally heat the surface. The combination of superhydrophobic gauze coated with carbon black nanoparticles along with the rubber black base showed that the evaporation was 14.09% for tap water, 13.16% for salt water, and 12.41% for DI water.