Insights Into the Mass Transfer Mechanisms of Nanofluids: A CO₂ Absorption Study

Abstract

α-Fe2O3 (hematite) and CuO nanoparticles were synthesized, characterized, and utilized to construct water-based nanofluids capable of CO2 absorption enhancement. The structure, morphology, surface, and bulk properties of the synthesized materials were investigated using field-emission scanning electron microscopy (FE-SEM), scanning electron microscopy (SEM), Fourier-transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), energy-dispersive X-ray spectroscopy (EDS), ζ, dynamic light scattering (DLS), pH, and viscosity analyses and measurements. The unclear and mysterious nature of the mass transfer mechanisms of nanofluids were investigated and confirmed by developing several approaches including new parameters for optimum and equilibrium conditions. The investigations revealed the maximum CO2 absorption enhancement of 63.79 and 38.72% for water–Fe2O3 and water–CuO nanofluids, respectively. A new observation about absorption trends was hypothesized and rationalized to be caused by the variation of surface charges and named the “electrostatic bulk effect”. The approach made it possible to categorize the reported mechanisms into bulky and interfacial groups and gave a concise, clear, and integrated insight into the mass transfer mechanisms, stability concept, and nanofluid component selection standards.

Improved structure of Zr-BTC metal organic framework using NH 2 to enhance CO 2 adsorption performance

“…On the other hand, different kinds of sorbents can mitigate such problems [9] because the adsorption technology can reduce the costs related to CO2 capture below the amine-based absorption process [10]. Commonly, activated carbons and zeolites have been utilized for gas removal and separation through adsorption, although their modification to improve selectivity is required [11,12].…”

Improved structure of Zr-BTC metal organic framework using NH2 to enhance CO2 adsorption performance

“…On the other hand, different kinds of sorbents can mitigate such problems 9 because the adsorption technology can reduce the costs related to CO 2 capture below the amine-based absorption process 10 . Commonly, activated carbons and zeolites have been utilized for gas removal and separation through adsorption, although their modification to improve selectivity is required 11 , 12 .…”