Experimental and molecular dynamics simulation study of toluene absorption by nanofluids

It is well known that the emission of volatile organic compounds (VOCs) is a significant threat to human health and the ecological environment, and toluene is a typical representative of aromatic VOCs, whose elimination makes an important contribution to the prevention and control of air pollution. Absorption is the classical process to eliminate air pollutants, but the application of absorption is often constrained by absorbent and gas-liquid mass transfer. In recent years, process intensification has become an important development in the chemical industry, and nanotechnology can effectively reduce mass transfer resistance and improve gas-liquid mass transfer effectiveness. This work aims to evaluate the effect of adding nanoparticles on the gas-liquid mass transfer process. The effects of TiO2, Al2O3, and SiO2 nanoparticles on the removal of toluene by green solvent low transition temperature mixtures (LTTM) were investigated experimentally and theoretically. The mass transfer enhancement factors of the toluene absorption process were measured at different concentrations and sizes of TiO2, Al2O3, and SiO2 nanoparticles, absorption temperatures and number of cycles. Molecular dynamics (MD) simulations of the microscopic properties of LTTM and toluene were performed. Based on the MD simulation results, the toluene density distribution, interaction energy, radial distribution function, spatial distribution function, and self-diffusion coefficient were calculated, which helped to explain the absorption mechanism of toluene gas. The findings demonstrated that nanoparticles can alter the gas-liquid mass transfer process, and provided a method and theoretical reference for enhancing the toluene absorption process.