Preparation of high antibiofouling amino functionalized MWCNTs/PES nanocomposite ultrafiltration membrane for application in membrane bioreactor

• PES membranes containing amino-functionalized MWCNT nanoplates were prepared.
• Fouling resistances of the UF membranes elucidated by activated sludge suspension filtration.
• Hydrophilicity and pure water flux of the modified membranes were improved.
• The prepared UF membranes can be suggested for membrane bioreactors.

Membrane bioreactor (MBR) is an innovative hybrid biotechnology for wastewater treatment. However, its application is constrained by its tendency to fouling. Various procedures are applied to reduce membrane fouling. In this work, nanocomposite membranes were prepared by embedding amino functionalized multi-walled carbon nanotubes (NH2-MWCNTs) and were used for improving membrane surface hydrophilicity and subsequently the reduction of the membrane biofouling. The NH2-MWCNTs were synthesized and used as nanofiller in preparation of polyethersulfone (PES) ultrafiltration (UF) membrane. The modified MWCNTs were blended with different weight percentage in the casting solution, i.e. 0.05, 0.1 and 1 wt.%. In this study, the effect of the NH2-MWCNTs on membrane morphology and antibiofouling property was investigated. The Fourier transform infrared (FT-IR) spectra analysis showed that the NH2 functional groups formed on the surface of MWCNTs. The nanocomposite membranes prepared with different contents of NH2-MWCNTs nanofiller were characterized using contact angle, scanning electron microscopy (SEM), and permeation tests. The SEM images displayed a finger-like and porous structure for all synthesized UF membranes. Contact angle measurements indicated that NH2-MWCNTs nanofiller improved the hydrophilicity of the obtained membranes. Fouling resistances of the membranes elucidated by activated sludge suspension filtration and measurements of flux recovery ratio (FRR). The results of the experiments revealed that the 0.1 wt.% NH2-MWCNTs membrane had the best permeability, hydrophilicity and antibiofouling properties. It was quite a surprise to discover that inclusion of only about 0.1 wt.% of the amino functionalized MWCNTs in the fabrication of membrane could spring up a generation of membrane with antibiofouling capability for MBRs.