Amphiphilic PVDF‐ g ‐PDMAPMA ultrafiltration membrane with enhanced hydrophilicity and antifouling properties

Fang

J of Applied Polymer Sci

et al. 2021

As the development of oilfield exploitation, more and more oil in water (O/W) emulsion was produced, thus efficient reverse demulsifier becomes increasingly important. In this paper, a series of novel reverse demulsifiers (R‐PED1 ~ 4) with the characteristics of polyacrylate and polycation were prepared. The structure of the product was verified by IR specter and 1H NMR. The thermal stability was studied with TGA and the molecular weight was obtained by GPC. Field evaluation results showed that the oil content in produced liquid after R‐PED4 treatment can be reduced from 1550 to 81 mg/L at R‐PED4 dosage was 50 mg/L. Furthermore, the demulsification mechanism of R‐PED was discussed. The R‐PED has good surface/interfacial activity. It can effectively reduce the oil–water interfacial film strength and reduce the zeta potential of oil droplets, which is beneficial for the coalescence of oil droplets. Especially, the interaction force between oil droplets was measured by the optical tweezers. R‐PED4 can increase the attraction force between oil droplets. Consequently, the contact time of oil droplets during the demulsification process can be prolonged and the coalescence of oil droplets also can be effectively promoted. The novel reverse demulsifier offers a new option for the oilfield produced liquid treatment.

Section: Resultsmentioning

confidence: 81%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Synthesis of a novel reverse demulsifier with the characteristics of polyacrylate and polycation and its demulsification performance

Fang

J of Applied Polymer Sci

et al. 2021

“…In addition, it increases the cleaning cost of the membrane and, finally, shortens the service life of the membrane. It is generally believed that a hydrophilic membrane could somehow overcome membrane fouling problems [4][5][6][7], because the hydrophilic membrane easily forms a hydration layer on the membrane surface that can effectively reduce the adhesion between pollutants and the membrane surface. In addition, the charge on the membrane surface is also an important factor that slows down membrane fouling [8], because some pollutants in water are charged.…”

Section: Introductionmentioning

confidence: 99%

Hydrophilic and Positively Charged Polyvinylidene Fluoride Membranes for Water Treatment with Excellent Anti-Oil and Anti-Biocontamination Properties

et al. 2022

Membrane fouling limits the rapid development of membrane separations. In this study, a blend membrane containing polycationic liquid (P(BVImBr1-co-PEGMA1)) is presented that can improve the antifouling performance of polyvinylidene fluoride (PVDF) membranes. By mixing the polycationic liquid into PVDF, an improved membrane-surface hydrophilicity and enlarged membrane porosity were detected. The water contact angle decreased from 82° to 67°, the porosity enlarged from 7.22% to 89.74%, and the pure water flux improved from 0 to 631.68 L m−2 h−1. The blend membrane surfaces were found to be always positively charged at pH 3~10. By applying the membranes to the filtration of oil/water emulsion and bovine serum albumin (BSA) solution, they showed a very high rejection rate to pollutants in wastewater (99.4% to oil droplets and 85.6% to BSA). The positive membrane surface charge and the increased membrane hydrophilicity resulted in excellent antifouling performance, with the flux recovery rates of the dynamic filtration tests reaching 97.3% and 95.5%, respectively. Moreover, the blend membranes demonstrated very low BSA adhesion and could even kill S. aureus, showing excellent antifouling properties.

J of Applied Polymer Sci

“…The solutes such as the proteins, colloidal particles, or organic matters may deposit onto the PVDF membrane pores, cause the pore blocking and finally lower the permeation flux, and shorten membrane lifespan. Comparably, a hydrophilic membrane surface demonstrates good antifouling ability, because the good hydrophilicity helps the formation of a hydration layer on the membrane surface that may resist the contact of contaminants onto the membrane surface …”

Section: Introductionmentioning

confidence: 99%

Fabrication of antifouling membranes by blending poly(vinylidene fluoride) with cationic polyionic liquid

Shen

Zhang

et al. 2019

Membrane fouling problem is now limiting the rapid development of membrane technology. A newly synthesized cationic polyionic liquid (PIL) [P(PEGMA-co-BVIm-Br)] was blended with poly(vinylidene fluoride) (PVDF) to prepare antifouling PVDF membranes. The PVDF/P(PEGMA-co-BVIm-Br) exhibited an increased surface hydrophilicity, the water contact angle was reduced from 77.8 (pristine PVDF) to 57.9 . More porous membrane structure was obtained by adding PIL into the blending polymers, as high as 478.0 L/m 2 Áh of pure water flux was detected for the blend PVDF membrane in comparison with pristine PVDF (17.2 L/m 2 Áh). Blending of the cationic PIL with PVDF gave a more positive surface charge than pristine PVDF membrane. Blend membranes showed very high rejection rate (99.1%) and flux recovery rate (FRR, 83.0%) to the positive bovine serum albumin (BSA), due to the electrostatic repulsion between the membrane surface and proteins. After three repeated filtration cycles of positive BSA, the blend PVDF membranes demonstrated excellent antifouling performance, the permeation flux of the membranes was recovered very well after a simple deionized water washing, and as high as 70% of FRR was obtained, the water flux was maintained at above 350 L/m 2 Áh.