Abstract
Global warming and high oil price have made the world to look into renewable energy like solar, wind, fuel cells etc. A massive amount of energy is released in the process of mixing of water of different salinity. This process is known as reverse electrodialysis. In this method, the production of electricity is free from thermal pollution, no output of pollutant, no radioactive waste. The Reverse Electroddialysis (RED) is the method where the voltage can be acquiring by the change in chemical potential between the concentration and dilute solution. The process which involves the flow of saline water and dilutes solutions through a cell in which the anion and cation exchanging membranes are present in between two electrodes where the electricity is generated. The electricity generation varies from cell to cell. Different types of membrane, electrode distance, type of electrode used, the concentration of feed, which are all the factors that influence the generation of power. In the setup of reverse electrodialysis, the smaller the membrane distance and the flow path length and thinner the membranes – higher power densities are obtained. Temperature changes also play an essential role. For the increased temperature in RED, the power densities will be maximum. The practical power output obtained is limited due to concentration polarization phenomena and spacer shadow effects. Other than the concentration polarization and spacer shadow effect, the fouling of the membrane occurs, which is also leads to the less power output. By improvement of those factors which results in a significant increase in the output of the RED process. This Review work consists of work of different types of reverse electrodialysis models the recent advancement from the beginning till the date. The surface properties like transport number, water contact angle, surface roughness have also been studied. Many mathematical models have also been illustrated via thermodynamical considerations, and some of the models predict the experimental results well, and their results are established.