Highly hydrophilic poly(vinylidene fluoride)/meso-titania hybrid mesoporous membrane for photocatalytic membrane reactor in water.

Meng Wang,Guang Yang,Peng Jin,Huanhuan Wang,Hao Tang,Yong Chen

doi:10.1038/srep19148

Abstract

The high hydrophobicity of poly(vinylidene fluoride) (PVDF) membrane remains an obstacle to be applied in some purification processes of water or wastewater. Herein, a highly hydrophilic hybrid mesoporous titania membrane composed of mesoporous anatase titania (meso-TiO2) materials inside the three-dimensional (3D) macropores of PVDF membrane was successfully prepared by using the dual-templated synthesis method combined with solvent extraction and applied as the photocatalytic membrane reactor for the photodegredation of organic dye in water. The structure and the properties of as-prepared hybrid membranes were characterized by scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS), transmission electron microscopy (TEM), X-ray diffraction (XRD), nitrogen adsorption–desorption and contact angle measurements. It was found that the hydrophilicity of PVDF membrane can be significantly improved by filling mesoporous TiO2 inside the 3D macropores of PVDF membrane. Moreover, such a PVDF/meso-TiO2 hybrid membrane exhibits promising photocatalytic degradation of dye in water due to the existence of mesoporous anatase TiO2 materials inside PVDF membrane. This study provides a new strategy to simultaneously introduce hydrophilicity and some desirable properties into PVDF and other hydrophobic membranes.

Highlights

The high hydrophobicity of poly(vinylidene fluoride) (PVDF) membrane remains an obstacle to be applied in some purification processes of water or wastewater
When PVDF present in PVDF/meso-TiO2 membrane was completely etched by calcination under high temperature, a number of free layers composed of rods could be obtained (Fig. S2), which almost duplicate the 3D macroporous structure of PVDF membrane
Based on all above results and discussion, the mechanism of such a photocatalytic membrane reactor for the photodegradation of methyl orange (MO) in water by filling meso-TiO2 in PVDF membrane can be illustrated as Fig. 8a–d, which should be mainly related to the three properties of as-prepared membranes including hydrophilicity, adsorption and photocatalysis

Summary

Introduction

The high hydrophobicity of poly(vinylidene fluoride) (PVDF) membrane remains an obstacle to be applied in some purification processes of water or wastewater. Since the surfaces and the inside-pores of PVDF membranes can provide a window of opportunity to be modified[19,20] and those hybrid mesoporous membranes prepared by using dual-templated synthesis method can introduce desirable properties into the original hydrophilic membranes[1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17], it is necessary to further explore the fabrication of hybrid mesoporous membranes by employing hydrophobic porous membranes as the hard templates. This study focusing on highly hydrophobic PVDF membrane was expected to be of profound significance because it enriched the dual-templated synthesis of hybrid mesoporous membranes, and offered a novel strategy to improve the properties of hydrophobic membranes

Methods

Results

Conclusion