Molecularly engineered switchable photo-responsive membrane in gas separation for environmental protection

Abstract

In recent years, stimuli-responsive materials have garnered interest due to their ability to change properties when exposed to external stimuli, making it useful for various applications including gas separation. Light is a very attractive trigger for responsive materials due to its speedy and non-invasive nature as well as the potential to reduce energy costs significantly. Even though light is deemed as an appealing stimulus for the development of stimuli-responsive materials, this avenue has yet to be extensively researched, as evidenced by the fewer works done on the photo-responsive membranes. Of these, there are even less research done on photo-responsive materials for the purpose of gas separation, thus, we have collected the examples that answer both these criteria in this review. This review covers the utilisation of photo-responsive materials specifically for gas separation purposes. Photo-chromic units, their integration into gas separation systems, mechanism and research that have been done on the topic so far are discussed.

Computational analysis of atomic binding energy for organosilicon‐ low‐density polyethylene‐coated silica embedded in polyvinylidene fluoride composite membrane for membrane gas absorption

“…The mass of the absorbed n-butanol (m n , g) can be determined by subtracting the dry weight (m p ) of the membrane from the wet weight (m p + n , g) of the membrane. The membrane porosity (ε, %) can be calculated using Equation ( 3) with the densities information of PVDF (ρ p ) and n-butanol (ρ n ) at 1.78 and 0.81 g/cm 3 , respectively.…”

“…Membrane contactors have proven to be a solution to many of the issues associated with the conventional gas absorption columns, such as flooding, entrainment, and foaming. [1][2][3] Although the existence of the membrane is the key to overcome the problems of traditional methods, it also poses additional resistance to mass transfer, especially when wetted. 4 Several factors, such as the choice of liquid absorbents, can lead to accelerated membrane wetting.…”

Fast light-switchable polymeric carbon nitride membranes for tunable gas separation

“…Indeed, responsive membranes have already been used in drug delivery applications, wherein the membranes can be activated by an external stimuli such as pH, temperature and ionic strength 5 . However, for dynamic applications such as gas separation, membranes that can be switched by light 6 , 7 , electric 8 and magnetic field are considered to be more suitable 9 . Recently, Knebel and coworkers reported an electric field-switchable metal-organic framework (MOF) membrane bearing zeolitic imidazolate framework, ZIF-8, which transforms into a polymorph structure under the influence of an electric field, thus resulting in a hindered gas transport 8 .…”

Functionalization of silica nanoparticles to reduce membrane swelling in CO2 absorption process

“…However, the drawback with silica nanoparticles is their tendency to agglomerate . This poses a major problem as it makes uniform dispersion of nanoparticles inside the polymer matrix difficult, as well as showing poor interfacial compatibility with the polymer . Functionalizing these originally hydrophilic silica nanoparticles to change its surface functional groups to hydrophobic could alleviate the problem.…”

“…18 This poses a major problem as it makes uniform dispersion of nanoparticles inside the polymer matrix difficult, as well as showing poor interfacial compatibility with the polymer. [19][20][21] Functionalizing these originally hydrophilic silica nanoparticles to change its surface functional groups to hydrophobic could alleviate the problem. For instance, by using silica nanoparticles that had been treated with hexamethyldisilazane (HMDS), Rezakazemi et al 22 were able to fabricate a composite membrane with augmented thermal stability and separation performance as the treated silica nanoparticles in the membrane had better hydrophobicity.…”