A review on recent advances of cellulose acetate membranes for gas separation

Abstract

This review thoroughly investigates the wide-ranging applications of cellulose-based materials, with a particular focus on their utility in gas separation processes. By focusing on cellulose acetate (CA), the review underscores its cost-effectiveness, robust mechanical attributes, and noteworthy CO₂ solubility, positioning it as a frontrunner among polymeric gas separation membranes. The synthesis techniques for CA membranes are meticulously examined, and the discourse extends to polymeric blend membranes, underscoring their distinct advantages in gas separation applications. The exploration of advancements in CA-based mixed matrix membranes, particularly the incorporation of nanomaterials, sheds light on the significant versatility and potential improvements offered by composite materials. Fabrication techniques demonstrate exceptional gas separation performance, with selectivity values reaching up to 70.9 for CO₂/CH₄ and 84.1 for CO₂/N₂. CA/PEG (polyethylene glycol) and CA/MOF (metal-organic frameworks) demonstrated exceptional selectivity in composite membranes with favorable permeability, surpassing other composite CA membranes. Their selectivity with good permeability lies well above all the synthesised cellulose. As challenges in experimental scale separation emerge, the review seamlessly transitions to molecular simulations, emphasizing their crucial role in understanding molecular interactions and overcoming scalability issues. The significance of the review lies in addressing environmental concerns, optimizing membrane compositions, understanding molecular interactions, and bridging knowledge gaps, offering guidance for the sustainable evolution of CA-based materials in gas separation technologies.

Fig. 1. Flow diagram of membrane permeation experiment setup. Reproduced with permission from ref. , an open access article under the terms of the Creative Commons Attribution License.

Fig. 2. Robeson plot for different polymers.

Fig. 3. Publications on cellulose acetate membrane through the years (Source: Scopus: 01/02/2024, search in TITLE-ABS-KEY with keywords of cellulose acetate AND membrane).

Fig. 4. CA synthesis using DBU/CO₂ switchable solvent system. Reprinted with permission from ref. , an open access article under the terms of the Creative Commons Attribution-Non Commercial 3.0 Unported License.

Fig. 5. Structure representation of cellulose acetate (CA) and polysulfone (PSF). Reproduced from ref. with permission from Springer Nature, copyright 2022.

Fig. 6. Schematic of MMMs of Cu-MOF-GO loading in CA-matrix. Reproduced with permission from ref. , an open access article distributed under the terms of the Creative Commons Attribution License.

Fig. 7. Robeson plot of the different CA composite membranes.

Fig. 8. Molecular structures of CAB/plasticizer systems. CAB cellulose acetate butyrate. Reprinted with permission from ref. , an open access article under the terms of the Creative Commons Attribution Licence.