Review on the Effect of Nanoparticles on Mass Transfer Coefficient in a Gas-Liquid System

Recently, the reduction of gaseous pollutants and greenhouse gases gets more attention by environmental scientists. The absorption of a gas into a liquid phase is one of the ways that is applied to remove a gaseous pollutant from environment. Therefore, a lot of researches have been carried out to improve the absorption performance. Nanotechnology is one of the techniques can be applied to absorption systems to enhance the mass transfer coefficient, resulting an improvement in absorption process. Recently, due to the development of nanotechnology, many researches on nanofluids have been carried out successfully as an effective way to enhance the mass transfer performance. This paper reviews the application of nanofluids for enhancing mass transfer during recent years. Although the mechanism of this enhancement is not stillclear, some reasons are suggested for the mass transfer enhancement in gas-liquid systems, especially ammonia absorption systems, the micro-convection in nanofluids because of the Brownian motion of nanoparticles and the gas holdup increasing in nanofluids are the most important ones of those reasons. Also the improvement of heat transfer at the gas– liquid interface increases the absorption potential. Key parameters of the absorption process are dose and type of nanoparticles and also inlet gas flow rate which are mostly investigated in the literatures.