High-permeability pluronic-based TiO2 hybrid photocatalytic membrane with hierarchical porosity: Fabrication, characterizations and performances

High-permeability Pluronic-based TiO2 hybrid photocatalytic membrane with hierarchical porosity has been fabricated via acid-catalyzed sol-gel method. Pluronic P-123 of different weight percentages was added to fine-tune the pore structure of the TiO2 sot and thus the resulting TiO2 layers. PVA was used as the pore fillers and binder. The sols were dip-coated layer-by-layer onto an alumina ceramic disc to fabricate hierarchically porous TiO2/alumina membrane with different porosity gradients. Physico-chemical and morphological characteristics of the membrane were investigated. Pluronic-based TiO2 photocatalytic membrane showed photo-induced super-hydrophilicity which is important for the accessibility of organic compound to the catalytic sites. The performances of the membrane were evaluated both in the batch photoreactor and continuous flow photoreactor operated in the dead-end filtration mode. In the batch photoreactor, the membrane was able to completely degrade rhodamine B despite the mass transfer limitation. The hierarchically porous Plu A membrane (which was coated with three different TiO2 layers of different pore structures) showed a high water permeability flux of 116 L m(2) h(-1) bar(-1) with the corresponding intrinsic membrane resistance of 3.1 x 10(12) m(-1). Plu A membrane also possessed excellent specific RhB removal of 2700 mg m(-2). The as-synthesized hybrid photocatalytic membrane showed a great potential for use in water and wastewater treatment owing to its fouling-control capability, high flux performances, good photocatalytic activity, and reusability. (C) 2013 Elsevier B.V. All rights reserved.