Process intensification in gas-liquid mass transfer by nanofluids: Mechanism and current status

Gas-liquid mass transfer is widely used in chemical, pharmaceutical, energy and other fields. Enhancing the gas-liquid mass transfer is helpful to achieve reduction in the various mass transfer equipment size, low emission of harmful gases, energy conservation and environmental protection. Adding solid nanoparticles of the third dispersed phase into the gas-liquid two-phase system is an important method used to enhance gas-liquid mass transfer. Enhancement of mass transfer using nanofluids has received increasing attention in recent years. A comprehensive literature review on gas-liquid mass transfer enhancement by nanofluids is here compiled. The aim of this review is to summarize and compare the development of gas-liquid mass transfer enhancement and the related mechanism. This review emphasize nanofluids preparation methods, nanofluids classification, important influencing factors (gas flow rate, liquid flow rate, gas inlet concentration, solid particles size, solid particles loading and temperature), enhancement mechanism (shuttle effect, hydrodynamic effect and inhibition of bubble coalescence) and further directions. This work also analyses experimental investigations by different authors on gas-liquid mass transfer utilizing nanofluids. Moreover, this review summarize literature on mass transfer in nanofluids stating the conflicting results and possible reasons. The outcomes of this review are expected to inspire new research for future developments and potential application of gas-liquid mass transfer in scientific research and industrial sectors. (C) 2021 Published by Elsevier B.V.