Publication: Effect of coating of polypropylene on polyvinylidenefluoride hollow fiber membrane via non-solvent for membrane gas absorption
Date
2022-09-01
Authors
Hassan, Amir Ikmal
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Abstract
Emissions of greenhouse gases mainly CO2 are mostly sourced from industries and automations. Conventional equipments such as scrubbers and absorbers were applied in plants to deal with excess gas emissions. This leads to implementation of membrane gas absorber (MGA) which has the potential as an alternative. Polyvinylidenefluoride (PVDF) or polypropylene (PP) material as base substrate was not sufficient to achieve the highest performance. Therefore, surface modification involving dip-coating was implemented. Coating steps involved PP layer coated on commercial PVDF hollow fiber membrane via dip-coating with and without non-solvent, hand-dip and automated dip to understand the effect of coating on its interaction, parameters and evaluated using MGA. Pre-coating of non-solvent using MEK improved membrane contact angle to 116.75' as opposed to ethanol,
105.84' proved MEK having better affinity and interaction to the substrate used. Study of PP concentration (10 – 55 mg/ml) and drying temperature (30 – 70'C) was studied with MEK which MP25 and MP40 at 50'C achieved the two highest contact angle at 116.75'and 118.35'. Study of coating speed (1 – 15 mm/s) and dipping time(10 – 60 s) were optimized at 5 mm/s and 10 s. Multilayer coating method (M1, M2 and M3) at increasing dipping cycle (2x and 3x) was addressed and M1 achieved the higher contact angle, 135.75'
owing to its high average surface roughness (Ra), 0.0809 µm via AFM compared to single dipping and other methods. MGA evaluation proved that pre-coated membranes with non-solvent have better CO2 flux. Besides, single coated membrane achieved higher overall flux as compared to 2x and 3x dipping cycle membranes. However, MP25 at 3x dipping cycle have lower wetting tendencies owing to 13.79% flux reduction while 1x dipping cycle experienced 20.59% flux reduction. In conclusion, interactions between components,
dip-coating parameters and performance of each membrane was optimized, addressed and elucidated.