Preparation and characterization of PVDF-filled MWCNT hollow fiber mixed matrix membranes for gas absorption by Al2O3 nanofluid absorbent via gas–liquid membrane contactor.

Talavari, Adel; Ghanavati, Bijan; Azimi, Alireza; Sayyahi, Soheil

• PVDF-filled MWCNT mixed matrix membranes were successfully fabricated. • Formation of finger-like pores was improved by adding MWCNT to the matrix. • Wettability resistance, porosity and gas permeance of the membranes were enhanced. • Gas absorption performance of the membranes was significantly improved. • Replacing the absorbent with Al 2 O 3 nanofluid further enhanced the performance. Porous polyvinylidene fluoride (PVDF)-filled MWCNT hollow fiber mixed matrix membranes were fabricated and applied for carbon dioxide absorption in a gas–liquid membrane contactor with Al 2 O 3 water-based nanofluid absorbent. The formation of MWCNTs' nanotubes was verified through Transmission electron microscopy (TEM) and Field emission scanning electron microscopy (FESEM) images while the resultant membranes were characterized for their morphology, gas permeation rate, pore size, porosity, surface hydrophilicity and wettability resistance. Upon the incorporation of MWCNT into the matrix, the formation of finger-like pores was facilitated and surface roughness increased. Gas permeation test results showed increasing the surface porosity and reducing the pore size. The surface contact angle also was improved from 83° ± 1.5 for the unfilled membrane to 103° ± 1.5 for the membrane containing 5 wt% CNT. CO 2 absorption flux also was enhanced considerably. For instance, the flux of the membrane containing 5 wt% CNT as the best performing membrane at a liquid velocity of 2.5 m/s and Al 2 O 3 water-based nanofluid as absorbent was 3.85 × 10−3 mol/m2 s which was approximately 200% higher than that of the plain membrane at the same operating conditions. A long-term absorption test also revealed non-wetting tendencies of the membranes as well as the unclogged membrane pores by the nanomaterials existed in the nanofluid absorbent. Therefore, it could be hypothesized that the improved membrane structure and synthesized nanofluid absorbent considering their superior performance to several commercial and in-house made membranes can be suitable alternatives to the current polymeric membranes and commercial used absorbents, respectively.

HOLLOW fibers; GAS absorption & adsorption; FIELD emission electron microscopy; CONTACT angle; POLYMERIC membranes; POLYVINYLIDENE fluoride

Chemical Engineering Research & Design: Transactions of the Institution of Chemical Engineers Part A, 2020, Vol 156, p478

0263-8762

Academic Journal

10.1016/j.cherd.2020.01.017