Preparation and characterization of a novel hydrophilic PVDF/PVA UF membrane modified by carboxylated multiwalled carbon nanotubes

This work elucidates the influence of graphene (G) and graphene oxide (GO) content on the desalination performance and scaling characteristics of G/polyvinylidene fluoride (G/PVDF) mixed matrix and GO/PVDF composite‐skin membranes, applied in a direct contact membrane distillation process (DCMD). Inclusion of high quality, nonoxidized, monolayered graphene sheets as polymer membrane filler, and application of a novel GO/water‐bath coagulation method for the preparation of the GO/PVDF composite films, took place. Water permeability and desalination tests via DCMD, revealed that the optimal G content was 0.87 wt%. At such concentration the water vapor flux of the G/PVDF membrane was 1.7 times that of the nonmodified reference, while the salt rejection efficiency was significantly improved (99.8%) as compared to the neat PVDF. Similarly the GO/PVDF surface‐modified membrane, prepared using a GO dispersion with low concentration (0.5 g/L), exhibited twofold higher water vapor permeate flux as compared to the neat PVDF, but however, its salt rejection efficiency was moderate (80%), probably due to pore wetting during DCMD. The relatively low scaling tendency observed for both G and GO modified membranes is primarily attributed to their smoother surface texture as compared to neat PVDF, while scaling is caused by the deposition of calcite crystals, identified by XRPD analysis. POLYM. ENG. SCI., 59:E262–E278, 2019. © 2018 Society of Plastics Engineers

Section: Introductionmentioning

confidence: 99%

Mixed Matrix PVDF/Graphene and Composite‐Skin PVDF/Graphene Oxide Membranes Applied in Membrane Distillation

Athanasekou

Sapalidis

Katris

et al. 2018

“…To prepare membranes with excellent filtration and mechanical properties, modifications are necessary. The improved methods include blending modifications , chemical modifications , and so forth . The preparation of polyethersulfone (PES) membrane by NIPS process was reported many times .…”

Section: Introductionmentioning

confidence: 99%

Preparation and characterization of PES/CA microporous membranes via reverse thermally induced phase separation process

Liu

Wei

et al. 2017

Self Cite

The blend polyethersulfone (PES)/cellulose acetate (CA) flat‐sheet microporous membranes were prepared by reverse thermally induced phase separation (RTIPS) process. The effects of CA content and coagulation bath temperature on membrane structures and properties were investigated in terms of membrane morphology, water contact angle, permeation performance, and mechanical properties. The cloud point results indicated that the cloud point decreased with the increasing content of CA. When the coagulation bath temperature was lower than the cloud point, the membrane formation process underwent nonsolvent induced phase separation (NIPS) process and dense skin layer and finger‐like structure were formed in membranes. These membranes had lower pure water flux and poor mechanical properties. But when the coagulation bath temperature was higher than the cloud point, the membrane formation process underwent RTIPS process. The porous top surface as well as porous cross‐section of the membranes were formed. Therefore, high pure water flux and good mechanical properties were obtained. The contact angles results indicated that the hydrophilicity of the prepared membranes improved obviously with the addition of CA. When the content of CA was 0.5 wt% and the membrane formation temperature was 323K, the PES/CA microporous membrane which was prepared via the RTIPS process displayed a optimal permeability of the pure water flux of 816 L m−2 h−1 and the BSA rejection rate of 49.5%, which showed an increase of 48.9% and 23.6% than that of pure PES membrane, respectively. Moreover, the mechanical strengths of the membranes obtained by RTIPS process were better than those membranes prepared by NIPS process. POLYM. ENG. SCI., 58:180–191, 2018. © 2017 Society of Plastics Engineers

“…It was well known that the UF performance of the membranes could be greatly affected by the pore structure of the membranes . The porosity value and the PSD of the resulted membranes were displayed in Table and Fig.…”

Section: Resultsmentioning

confidence: 99%

Preparation of PVDF ultrafiltration membranes using PVA as pore surface hydrophilic modification agent with improved antifouling performance

Zheng

Duan³

et al. 2018

Novel polyvinylidene fluoride (PVDF) ultrafiltration (UF) membranes were facilely fabricated using polyvinyl alcohol (PVA) aqueous solution as the coagulation bath through phase inversion method. In the process, PVA was introduced into the pore surfaces of the PVDF membranes via the interdiffusion of the non‐solvent water and the solvent. The effects of PVA content in the coagulation bath on membrane properties were systematically discussed. The results indicated that the increase of PVA content in coagulation bath resulted in the formations of the more sponge‐like structures and the higher surface hydrophilicity. Smaller pore size led to lower water flux and higher bovine serum albumin rejection. Fouling resistance measurement indicated that the membranes made in PVA/water coagulation bath had higher flux recovery ratio (92.1%) than the membrane made in a pure water bath (71.0%). Furthermore, mechanical property test revealed that the resulting membranes had high tensile strength and Young's modulus. In this work, we found that the morphology and the property of the novel PVDF membranes could be determined by the PVA content in the coagulation bath. POLYM. ENG. SCI., 59:E384–E393, 2019. © 2018 Society of Plastics Engineers