Hydrophobic SiO₂ nanoparticle‐induced polyvinylidene fluoride crystal phase inversion to enhance permeability of thin film composite membrane

Abstract

Thin film composite (TFC) membrane can get rid of small molecular contaminants and salts with a very high efficiency, thus exhibiting promising potential for addressing the emerging problem of a clean water shortage. In this work, a new type of TFC membrane was prepared by interfacial polymerization of two monomers (MPD and TMC) on surface of SiO 2 /polyvinylidene fluoride (PVDF) substrate. The maximum flux of 3.16 L m −2 h −1 Bar −1 was achieved for the optimized hydrophobic SiO 2 nanoparticles well dispersed in PVDF substrate, which is 2.6 times higher than that of 1.21 L m −2 h −1 Bar −1 for the commercial cellulose triacetate reverse osmosis membrane. The improved performance of TFC membrane could be attributed to the higher compaction resistance of SiO 2 /PVDF substrate. Further analysis revealed that PVDF crystal phase inversion induced by superhydrophobic SiO 2 nanoparticles obviously enhanced the intramolecular and intermolecular hydrogen bonds between PVDF polymer molecules. Additionally, the narrower finger-like pore size and thicker pore wall of SiO 2 /PVDF substrate also played significant roles in enhancing the compaction resistance of PVDF membrane. This work also provides a proof-of-concept demonstration of high permeability substrates for effective flux enhancement of TFC membranes.

Polymer Nanocomposite Ultrafiltration Membranes: The Influence of Polymeric Additive, Dispersion Quality and Particle Modification on the Integration of Zinc Oxide Nanoparticles into Polyvinylidene Difluoride Membranes

“…Such increase in hydrophilicity was also reported in many cases [ 13 , 14 , 15 , 16 , 17 , 18 , 19 , 20 , 21 , 23 , 24 ]. In seven studies, the permeability decreased at higher nanoparticle concentrations; this was attributed to pore blocking by agglomerated nanofiller [ 14 , 15 , 16 , 17 , 18 , 23 , 25 ]. That the addition of nanoparticles solely led to a decrease in permeability was reported in three studies [ 11 , 27 , 28 ], while two of these studies also reported an increase in hydrophilicity [ 11 , 28 ].…”

“…This was demonstrated in 14 studies, and in some of the cases this was attributed to the measured increase in surface hydrophilicity caused by the hydrophilic particles [ 13 , 14 , 15 , 16 , 17 , 18 , 19 , 20 , 21 , 22 , 23 , 24 , 25 , 26 ]. Such increase in hydrophilicity was also reported in many cases [ 13 , 14 , 15 , 16 , 17 , 18 , 19 , 20 , 21 , 23 , 24 ]. In seven studies, the permeability decreased at higher nanoparticle concentrations; this was attributed to pore blocking by agglomerated nanofiller [ 14 , 15 , 16 , 17 , 18 , 23 , 25 ].…”

“…Since these are all metal oxides, it is expected that their effect on the PVDF membrane’s formation will be similar to the effect of zinc oxide because of similar hydrophilicity and Hansen solubility parameters [ 12 ]. An overview table, showing the most important results of these studies [ 11 , 13 , 14 , 15 , 16 , 17 , 18 , 19 , 20 , 21 , 22 , 23 , 24 , 25 , 26 , 27 , 28 ], is provided in the Supplementary Materials ( Table S1 ), and the most important results are recapitulated in the following paragraphs.…”

“…The authors attributed this to the increased viscosity of the dope solution, which was caused by the addition of the nanoparticles. The macro-void formation in the membrane cross-section was decreased in five studies, likely caused by the same change in viscosity [ 14 , 16 , 18 , 25 , 28 ]. In contrast, in three other studies an increase in macro-void formation tendency with nanofiller addition was observed [ 17 , 20 , 21 ], and one study showed an initial increase in macro-void formation that deceased at higher particle concentration [ 15 ].…”

Enhancing mechanical performance and wet‐skid resistance of emulsion styrene butadiene rubber/natural rubber latex composites via in‐situ hybridization of silanized graphene oxide and silica

“…In the infrared spectrum of SiO 2 , the O H bending vibration absorption peak, Si O stretching vibration absorption peak and Si OH characteristic peak are located at 1637 cm À1 , 1096 cm À1 , 952 cm À1 , and the O H absorption peak of structure water is located at 3436 cm À1 , which indicates that SiO 2 is successfully generated in situ. 29 Compared with SiO 2 , SiO 2 -KH550 has a new characteristic peak at 2956 cm À1 , which is consistent with the asymmetric stretching of the methyl group of KH550. 30 In addition, the characteristic peak of Si-OH at 952 cm À1 disappears, and a new characteristic peak is generated at 1562 cm À1 due to the symmetrical deformation vibration of NH 2 .…”