PVDF–TiO₂ composite hollow fiber ultrafiltration membranes prepared by TiO₂ sol–gel method and blending method

Abstract

Organic-inorganic polyvinylidene fluoride (PVDF)-titanium dioxide (TiO 2 ) composite hollow fiber ultrafiltration (UF) membranes were prepared by TiO 2 solgel method and blending method, respectively. The membranes were characterized in terms of microstructure, hydrophilicity, permeation performance, thermal stability, and mechanical strength. The experimental results indicated that PVDF-TiO 2 composite UF membranes exhibited significant differences in surface properties and intrinsic properties because of the addition of inorganic particles. The TiO 2 particles improved the membrane strength and thermal stability of PVDF-TiO 2 composite UF membranes. In particular, hydrophilicity and permeability increased dramatically with the increase of TiO 2 , whereas the retention property of UF membranes was nearly unchanged. However, high TiO 2 concentration induced the aggregation of particles, resulting in the decline of hydrophilicity and permeability. Compared with PVDF-TiO 2 composite hollow fiber UF membranes prepared by TiO 2 blending method, PVDF-TiO 2 composite hollow fiber UF membranes prepared by TiO 2 sol-gel method formed a dispersed inorganic network, and the stronger interaction between inorganic network and polymeric chains led to TiO 2 particles being uniformly dispersed in UF membranes.

Comparison between hydrophilic and hydrophobic metal nanoparticles on the phase separation phenomena during formation of asymmetric polyethersulphone membranes

“…The presence of agglomerations can be principally caused by the high surface energy of the metal nanoparticles, which tend to agglomerate for diminishing their surface energy to reach a more stable state. For this reason, these agglomerations lead to a bad distribution of metal nanoparticles along both polymer structure and surface, negatively altering membrane flux and antifouling properties by changing parameters such as surface roughness and hydrophilicity [47,51,52]. Some researchers suggested that the preparation of nanoparticles with a stabilizer and the use of ultrasonication could be applied in order to prevent the agglomeration of metal nanoparticles [53,54].…”

Organic-inorganic hybrid membranes in separation processes: a 10-year review

“…This causes difficulty in dispersing the nanoparticles during membrane fabrication. However, Yu et al (2009) suggested that an increment in concentration of nanoparticles could lead to an increase in nanoparticle agglomeration. Besides, Gilbert et al (2009) suggested that ionic strength and pH of the solution also could induce agglomeration between nanoparticles.…”

A new approach to improve antifouling property of PVDF membrane using in situ polymerization of PAA functionalized TiO2 nanoparticles

“…Entrapping of TiO 2 as inorganic filler in polymer matrix [1,22,[25][26][27], depositing of nanoparticles on membrane surface by self-assembly method [11,23,[28][29][30] and coating of TiO 2 blended new polymer on membrane surface [31].…”