Theoretical and experimental investigation of CO2 solubility in nanofluids containing NaP zeolite nanocrystals and [C12mim][Cl] ionic liquid

Abstract

AbstractToday, CO2 separation is very important, both as an environmental issue and also in various industries. In this study, the water‐based nanofluid of NaP zeolite nanocrystals and 1‐dodecyl‐3‐methylimidazolium chloride ([C12mim][Cl]) ionic liquid were mixed and tested experimentally for CO2 absorption in an isothermal high pressure cell equipped with magnetic stirring. Zeolite nanocrystals were synthesized via the hydrothermal approach and characterized. A series of experiments were performed at different conditions to investigate the impact of various parameters, including nanoparticle type, nanoparticle concentration, stabilizer concentration, and the vessel's initial pressure, on CO2 solubility. It was found that 0.02 wt.% of zeolite nanoparticles, 0.4 wt.% of [C12mim][Cl] ionic liquid, and 0.05 wt.% of sodium dodecyl benzene sulphonate (SDBS) in nanofluids result in higher absorption of CO2 compared to other concentrations. Furthermore, CO2 absorption was increased by increasing ionic liquid and surfactant concentration up to a certain value near critical micelle concentration, but after that the CO2 absorption was decreased. The overall CO2 absorption enhancement at 20 bar for 0.02 wt.% zeolite and ZnO water‐based nanofluids with 0.4% [C12mim][Cl] ionic liquid and 0.02 wt.% SDBS were 26.9%, 21.5%, 21.2%, and 17% in comparison to pure water, respectively. In an absorption process using nanofluids, besides the influence of the mentioned parameters, the micro‐convection caused by Brownian motion and the grazing effect of nanoparticles should be noted. Considering the micro‐convection and grazing effects, a theoretical model should take into account the Brownian motion and grazing effects on the mass transfer rate in nanofluids to investigate the absorption enhancement by nano‐particles.