Study on the Fabrication of Superhydrophobic Microporous Polypropylene Flat Membrane Using <i>In Situ</i> Synthesis of Modified Fluorinated Silica Nano Particles

Abstract

The wettability is the most important features of membrane, when it works as contactors. Although the membrane contactors offer many advantages over conventional contacting equipments, additional mass transfer resistance is introduced when micropores are filled with aqueous absorbents. Therefore, fabrication of superhydrophobic membrane which prevents diffusion of aqueous absorbent into membrane pores is a highly challenging task. In this work, superhydrophobic polypropylene (PP) membrane was fabricated using in situ synthesis of silica nano particles via thermally induced phase separation (TIPS) method. Flat sheet fabricated PP membranes were casted with methanolic solution containing various ratios of perfluorooctyltriethoxysilane (PFOTES)/ tetraethylortosilicate (TEOS) and then sol-gel reaction between the mixed silances was completed. The contact angle of coated membrane was reached to 168 degree, when the percentage of PFOTES/TEOS was fixed at 50% (mol/mol). Interestingly, due to the microporous structure of PP membrane, the synthesized fluorinated silica nanoparticles were observed on the surface as well as in the cross-sectional area of the membrane. Field emission scanning electron microscopy (FE-SEM) images were confirmed this point. Chemical structure of the coated membranes with 50% PFOTES was compared with pure PP membrane using ATR-IR. In order to evaluate the operational performance, coated membranes were immersed in aqueous solutions of mono ethanol amine (MEA), di ethanol amine (DEA) and pure water. In comparison with pure PP membrane, obtained results showed that the wettability of coated membranes was considerably decreased.

Computational Fluid Dynamics Simulation of a Membrane Contactor for CO2 Separation: Two Types of Membrane Evaluation

“…Choosing the hollow-fiber membrane and absorbent solution are the most important parameters that can specify the efficiency of the HFMC process. Different kinds of liquids in various HFMCs were examined, but the membranes with higher hydrophobicity like polypropylene (PP) and the solution with lower membrane wettability like monoethanolamine (MEA) are more appreciated [51][52][53][54][55][56][57]. Kreulen et al [58] studied the absorption of CO 2 into water-glycerol mixtures using PP hollow fibers.…”

CO2 Stripping from Monoethanolamine through a Polypropylene/CH3SiO2 Composite Hollow‐Fiber Membrane Contactor

“…Although a lot of research has been undertaken on CO 2 absorption using different composite hollow‐fiber membrane contactors, there is a dearth of literature on CO 2 stripping utilizing PP composite hollow‐fiber membranes in a membrane contactor system. PP is one of the most widely used polyolefins, because of excellent characteristics such as balanced physical and mechanical properties, high resistance to water and chemical environments, excellent processability, and low cost 23, 24. Due to the low surface tension of the chemical absorbents and the morphological and chemical changes caused in the membrane surface structure 7, 9, PP membranes are incompatible with chemical absorbents for long‐term operation.…”

Study on the fouling behavior of silica nanocomposite modified polypropylene membrane in purification of collagen protein

“…PP membrane was pre-treated by Piranha solution (mixture of H 2 O 2 and H 2 SO 4 ) to create hydroxyl functional group ( OH) on the membrane surface (Raveshian et al, 2014). The existence of hydroxyl group ensures the chemical grafting of silane coupling agents on to the membrane surface.…”