No abstract

The emission of greenhouse gases, especially CO2, has become a major cause of environmental degradation, and carbon capture, utilization, and storage (CCUS) is a proposed solution to mitigate its impact. Nanofluids, a relatively new method for CO2 absorption, have gained attention in recent years. This review focuses on conventional methods for preparing nanofluids along with techniques to improve their stability and enhance the CO2 absorption and desorption mechanisms. Additionally, the influences of factors, i.e., nanoparticle and base solution types as well as nanoparticle concentration, on the CO2 absorption process are summarized. Furthermore, models that can predict the absorption of CO2 accurately are outlined. It is found that the types of both base liquids and nanoparticles have an important impact on the absorption by nanofluids. In-depth studies on the predictive capabilities of artificial intelligence (AI) models hold immense potential in this regard. This review also puts forth effective strategies to address prevailing challenges. This will provide a solid theoretical basis for this field and underscore the promising potential of nanofluids as CO2 solvents. There are still many unexplored aspects to be considered, such as the economic viability and energy consumption of this technology.

Nanoparticles are being used in the CO2 solvents to improve the capture performance. Herein, a 2D model is proposed to study the CO2 capture performance from a gaseous mixture using a hollow fiber membrane contactor (HFMC). Both water‐based nanofluids of carbon nanotubes (CNT) and SiO2 are deployed as the carbon absorbents. It is verified that Brownian motion and grazing effect are the major reasons to enhance the mass transfer of nanofluids. The simulation findings show that the modeling data conform well with the experimental studies. The root‐mean‐square errors for SiO2 nanofluid and CNT nanofluid are 2.37% and 2.56%, respectively. When the amounts of nanoparticles increase between 0.02 and 0.06 wt%, CO2 capture efficiencies of SiO2 and CNT nanofluids increase by 7.92% and 13.17%, respectively. Also, the CNT nanofluid has a better capture performance than the SiO2 nanofluid. Furthermore, research is conducted into how membrane characteristics affect HFMC performance. It is indicated that increasing the membrane porosity and decreasing the membrane tortuosity have a positive impact on the capture efficiency. This work demonstrates the potentials in the use of nanoparticles in CO2 solvents and provides a solid theoretical basis for nanofluids to significantly enhance gas absorption.