Molecular investigation into the effect of carbon nanotubes interaction with CO2 in molecular separation using microporous polymeric membranes

Mahboubeh Pishnamazi,Mashallah Rezakazemi,Saeed Shirazian,Ali Taghvaie Nakhjiri,Azam Marjani,Arezoo Sodagar Taleghani

doi:10.1038/s41598-020-70279-5

Abstract

The use of nanofluids has been recently of great interest to separate acidic contaminants such as CO2. The main objective of this research is to assess the influence of carbon nanotubes (CNTs) addition to distilled water on enhancing the CO2 molecular separation through a porous membrane contactor (PMC). For this aim, a comprehensive model is developed based on non-wetted and counter-current operational modes to evaluate the principal mass and momentum transport equations in tube, membrane and shell compartments of PMC. Consequently, a CFD-based axisymmetrical simulation is implemented according to finite element technique (FET) to prognosticate the results. It is found from the results that the addition of 0.1 wt% carbon nanotubes (CNTs) particles to water significantly enhances the mass transfer and consequently the CO2 molecular separation efficiency from 38 to 63.3%. This considerable enhancement can be justified due to the existence of two momentous phenomena including Brownian motion and Grazing effect, which enhance the mass transport of CO2 molecules in the PMC. Moreover, the effect of CNTs concentration, some membrane's parameters such as number of hollow fibers and porosity and also some module's design parameters including module radius and length on the CO2 separation performance are investigated in this paper as another highlight of the current work.

Highlights

The use of nanofluids has been recently of great interest to separate acidic contaminants such as C O2
Both surface plots illustrate that the CO2 molecular concentration in the tube pathway of porous membrane contactor (PMC) is much lower than the membrane and shell side, which is attributed to the diffused CO2 sequestration by the distilled water and carbon nanotubes (CNTs) water-based nanofluid as liquid absorbents
Solution of principle equations in tube, membrane and shell compartments of PMC related to mass and momentum transport process are conducted using computational fluid dynamics (CFD), which operates based on finite element technique (FET)

Summary

Introduction

The use of nanofluids has been recently of great interest to separate acidic contaminants such as C O2. The main objective of this research is to assess the influence of carbon nanotubes (CNTs) addition to distilled water on enhancing the C O2 molecular separation through a porous membrane contactor (PMC). For this aim, a comprehensive model is developed based on non-wetted and counter-current operational modes to evaluate the principal mass and momentum transport equations in tube, membrane and shell compartments of PMC. It is found from the results that the addition of 0.1 wt% carbon nanotubes (CNTs) particles to water significantly enhances the mass transfer and the C O2 molecular separation efficiency from 38 to 63.3% This considerable enhancement can be justified due to the existence of two momentous phenomena including Brownian motion and Grazing effect, which enhance the mass transport of C O2 molecules in the PMC. Nanofluids consist of nanoparticles (NPs) such as Fe3O4, Al2O3, SiO2, and CNTs, dispersed in base fluids like water and amine solutions[13,14,15]

Objectives

Results

Conclusion