Impacts of Multilayer Hybrid Coating on PSF Hollow Fiber Membrane for Enhanced Gas Separation

Abstract

One of the most critical issues encountered by polymeric membranes for the gas separation process is the trade-off effect between gas permeability and selectivity. The aim of this work is to develop a simple yet effective coating technique to modify the surface properties of commonly used polysulfone (PSF) hollow fiber membranes to address the trade-off effect for CO2/CH4 and O2/N2 separation. In this study, multilayer coated PSF hollow fibers were fabricated by incorporating a graphene oxide (GO) nanosheet into the selective coating layer made of polyether block amide (Pebax). In order to prevent the penetration of Pebax coating solution into the membrane substrate, a gutter layer of polydimethylsiloxane (PDMS) was formed between the substrate and Pebax layer. The impacts of GO loadings (0.0–1.0 wt%) on the Pebax layer properties and the membrane performances were then investigated. XPS data clearly showed the existence of GO in the membrane selective layer, and the higher the amount of GO incorporated the greater the sp2 hybridization state of carbon detected. In terms of coating layer morphology, increasing the GO amount only affected the membrane surface roughness without altering the entire coating layer thickness. Our findings indicated that the addition of 0.8 wt% GO into the Pebax coating layer could produce the best performing multilayer coated membrane, showing 56.1% and 20.9% enhancements in the CO2/CH4 and O2/N2 gas pair selectivities, respectively, in comparison to the membrane without GO incorporation. The improvement is due to the increased tortuous path in the selective layer, which created a higher resistance to the larger gas molecules (CH4 and N2) compared to the smaller gas molecules (CO2 and O2). The best performing membrane also demonstrated a lower degree of plasticization and a very stable performance over the entire 50-h operation, recording CO2/CH4 and O2/N2 gas pair selectivities of 52.57 (CO2 permeance: 28.08 GPU) and 8.05 (O2 permeance: 5.32 GPU), respectively.

Thin Film Mixed Matrix Hollow Fiber Membrane Fabricated by Incorporation of Amine Functionalized Metal-Organic Framework for CO2/N2 Separation

“…The performance of the prepared Pebax ® 2533-UiO-66-NH 2 /PP thin film mixed matrix hollow fiber membranes were compared with Pebax ® -based mixed matrix membranes containing various types of fillers ( Table 1 ). The gas separation performance of Pebax ® 2533-UiO-66-NH 2 /PP thin film mixed matrix hollow fiber membrane containing 10 wt% UiO-66-NH 2 is comparable with previous reported Pebax ® -based mixed matrix membranes containing various types of fillers in literature [ 14 , 33 , 40 , 44 , 45 , 46 , 47 , 48 , 49 , 50 , 51 , 52 ]. The prepared membrane shows a high CO 2 /N 2 ideal selectivity equal to 37 with a CO 2 permeance 25.81 GPU at feed pressure 2 bar.…”

Express Method of Preparation of Hollow Fiber Membrane Samples for Spinning Solution Optimization: Polysulfone as Example

“…The 2019 review contains studies on the influence of the nature and composition of the internal coagulant, its temperature, and the contact time of the casting polymer solution with it [10]. The latest review of 2020 contains research on the development of casting methods of HF membranes that are safe for humans and the environment [11] Polysulfone (PSf) is one of the most common polymers for the manufacture of HF membranes for micro-, ultrafiltration, gas separation, and membrane contactors [12][13][14]. In scientific works on the formation of HF membranes from this polymer, the influence of the molecular weight and concentration of the matrix polymer, the solvent used, the type of pore-forming agent, its molecular weight and concentration, the nature and composition of the coagulant on their transport and separation properties has been studied in detail [15][16][17][18].…”

Impacts of Green Synthesis Process on Asymmetric Hybrid PDMS Membrane for Efficient CO2/N2 Separation

“…To improve the separation performance of membranes, it has been suggested that different organic or inorganic materials, such as fluorescent material (TPE) [ 8 ], metal nanoparticles [ 9 ], graphene oxide (GO) [ 10 ], carbon nanotubes (CNTs) [ 11 ], metal–organic frameworks (MOFs) [ 12 ], TiO 2 [ 13 , 14 ] and silica [ 15 , 16 ] are incorporated. Compared with other materials, silica is a common and low-cost functional filler for organic–inorganic hybrid membranes.…”