Polyvinylidene Fluoride Membrane Via Vapour Induced Phase Separation for Oil/Water Emulsion Filtration

Normi Izati Mat Nawi; Nur Rifqah Sait; Muhammad Roil Bilad; Norazanita Shamsuddin; Juhana Jaafar; Nik Abdul Hadi Nordin; Thanitporn Narkkun; Kajornsak Faungnawakij; Dzeti Farhah Mohshim

doi:10.3390/polym13030427

Polyvinylidene Fluoride Membrane Via Vapour Induced Phase Separation for Oil/Water Emulsion Filtration

Polymers (Basel). 2021 Jan 29;13(3):427. doi: 10.3390/polym13030427.

Authors

Normi Izati Mat Nawi¹, Nur Rifqah Sait¹, Muhammad Roil Bilad^{1

2}, Norazanita Shamsuddin³, Juhana Jaafar⁴, Nik Abdul Hadi Nordin¹, Thanitporn Narkkun⁵, Kajornsak Faungnawakij⁵, Dzeti Farhah Mohshim⁶

Affiliations

¹ Chemical Engineering Department, Universiti Teknologi PETRONAS, Seri Iskandar 32610, Perak, Malaysia.
² HICoE-Centre for Biofuel and Biochemical Research, Institute of Self-Sustainable Building, Universiti Teknologi PETRONAS, Seri Iskandar 32610, Perak, Malaysia.
³ Faculty of Integrated Technologies, Universiti Brunei Darussalam, Jalan Tungku Link BE1410, Brunei.
⁴ Advanced Membrane Technology Research Center (AMTEC), School of Chemical and Energy Engineering (SCEE), Universiti Teknologi Malaysia (UTM), Johor 81310, Malaysia.
⁵ National Nanotechnology Center (NANOTEC), National Science and Technology Development Agency (NSTDA), 111 Thailand Science Park, Pathum Thani 12120, Thailand.
⁶ Petroleum Engineering Department, Universiti Teknologi PETRONAS, Seri Iskandar 32610, Perak, Malaysia.

Abstract

Membrane-based technology is an attractive option for the treatment of oily wastewater because of its high oil removal efficiency, small footprint and operational simplicity. However, filtration performance is highly restricted by membrane fouling, especially when treating oil/water emulsion as a result of strong interaction between oil droplets and the hydrophobic property of the membrane. This study explores the fabrication of polyvinylidene fluoride (PVDF)-based membrane via the vapour induced phase separation (VIPS) method while incorporating polyvinyl pyrrolidone (PVP) as a hydrophilic additive to encounter membrane fouling issues and improve membrane filterability. The resulting membranes were characterized and tested for oil/water emulsion filtration to evaluate their hydraulic, rejection and anti-fouling properties. Results show that the changes in membrane morphology and structure from typical macrovoids with finger-like substructure to cellular structure and larger membrane pore size were observed by the prolonged exposure time from 0 to 30 min through the VIPS method. The enhanced clean water permeability is attributed to the addition of PVP-LiCl in the dope solution that enlarges the mean flow pore size from 0.210 ± 0.1 to 7.709 ± 3.5 µm. The best performing membrane was the VIPS membrane with an exposure time of 5 min (M-5), showing oil/water emulsion permeability of 187 Lm^-2 h^-1 bar^-1 and oil rejection of 91.3% as well as an elevation of 84% of clean water permeability compared to pristine PVDF developed using a typical non-solvent induced phase separation (NIPS) method. Despite the relatively high total fouling, M-5 was able to maintain its high permeability by water flushing as a simple operation for membrane fouling control. The performance was achieved thanks to combination of the large mean flow pore size and hydrophilic property from residual PVP in the membarne matrix. Overall, the results demonstrate the potential of the optimum VIPS method in the presence of PVP and LiCl additives for oil/water emulsion treatment.

Keywords: PVDF membrane; VIPS; antifouling; membrane fouling; membrane technology; oil/water emulsion; oily wastewater.