110th Anniversary: Selection of Cross-Linkers and Cross-Linking Procedures for the Fabrication of Solvent-Resistant Nanofiltration Membranes: A Review

Abstract

Separation in organic mixtures is challenging but inevitable in many chemical and pharmaceutical processes. A membrane-based technique known as organic solvent nanofiltration (OSN) offers a sustainable and reliable solution due to its characteristics of low energy consumption and high efficiency. However, fabrication of a robust membrane that can maintain its separation performance in direct contact with organic solvents for a long period of time is challenging. The most common way to make a polymeric membrane resistant to organic solvents is to cross-link it with a three-dimensional network of polymer chains. However, selection of the right cross-linker for a particular polymer may not be very straightforward. Therefore, in this review, we aim to briefly introduce the common materials used for the fabrication of OSN membranes and demonstrate the state-of-art cross-linking procedures to improve the chemical stability of the membranes. This review may be helpful to researchers when selecting and modifying materials for the development of OSN membranes.

Polybenzimidazole Membrane Crosslinked with Epoxy-Containing Inorganic Networks for Organic Solvent Nanofiltration and Aqueous Nanofiltration under Extreme Basic Conditions

“…Thus, in the pharmaceutical and petrochemical industries, an efficient separation of organic solvents should be implemented not only to reduce energy consumption, but also to promote the recycling of solvents. In this context, organic solvent nanofiltration (OSN) or solvent-resistant nanofiltration has been emerging as a desired separation process due to several advantages over conventional processes such as low energy consumption and operation cost [4][5][6]. Modular design and small footprint, which are key advantages of membrane-based separation, are also highly beneficial in practical applications.…”

Designing organic solvent separation membranes: polymers, porous structures, 2D materials, and their combinations

“…To make membrane technology competitive with conventional separation technologies, membranes exhibiting superior separation properties and excellent long-term stability are sought. To this end, materials with advanced separation properties have been reviewed, including polymers, 8,14 crosslinked polymers, 15,16 porous polymeric and carbonaceous materials, 17 metal-organic frameworks (MOFs), 18,19 covalent organic frameworks (COFs), 18,20 two-dimensional (2D) materials, 21 thin-film composite (TFC) membranes, 22 surfacemodified membranes, 23 and mixed-matrix membranes (MMMs). 24,25 Modeling of liquid transport in membranes has also been described, [26][27][28][29] and important membrane materials were highlighted.…”

Thin-Film Composite Nanofiltration Membranes for Non-Polar Solvents

“…With respect to the sustainability, the membrane-based OSN separation process has been recognized as a best separation technology due to its low energy requirements, low solid waste generation, low carbon footprint, low labor intensity, straightforward scale-up, stability in harsh environments (pH, high temperature, and solvents), mild operating conditions (room temperature and low pressure), easy solvent swap from high to low boiling point solvents, and simultaneous removal of solutes from different chemical environments [ 4 , 5 ].…”