Advanced Membrane Material for Membrane Bio-Reactor

Advanced Membrane Material for Membrane Bio-Reactor

Hiroki Minehara, Kouichi Dan, Yohito Ito, Hiroo Takabatake and Masahiro Henmi, Toray Industries, Inc., Shiga, Japan

Abstract:

Membrane bio-reactor (MBR) system for wastewater treatment is attracting growing attention due to their compact design and high quality outputs. It is well known, however, that filtration of bacterial suspensions in bio-reactor leads to membrane fouling. Fouling occurs frequently and more seriously on hydrophobic membranes than hydrophilic ones because of hydrophobic interaction between the solutes and membrane material.

In this study, an investigation of hydrophilic polymer blends consisting of PVDF and hydrophilic polymers as a new low fouling membrane material was conducted. Hydrophilic poly(ethylene oxide) grafted poly(methyl methacrylate) copolymer (PMMA-g-PEO) was synthesized. An analysis of intermolecular interaction between various polymers and fouling ingredients was performed. Equilibrium adsorbed amount of organic compounds was quantitatively evaluated using surface plasmon resonance sensor. The results correlated with surface hydrophilicity of the polymers.

PMMA-g-PEO copolymer showed high compatibility with poly(vinylidene fluoride) (PVDF). PVDF/PMMA-g-PEO blends had good membrane forming property. The blend membranes showed excellent low-fouling characteristic and high filtration performance compared to existing PVDF membrane in continuous operation of MBR.

In conclusion, the modification of PVDF by blending with hydrophilic polymers was found to be an effective strategy to obtain low-fouling membrane material for MBR. The results also revealed that SPR analysis of intermolecular interaction was a strong tool for evaluating low-fouling characteristic of polymer membranes.