Fabrication and properties of an immobilized P25TiO2-montmorillonite bilayer system for the synergistic photocatalytic–adsorption removal of methylene blue

• P25TiO2 and montmorillonite was integrated via an immobilized bilayer approach.
• Synergistic dual photocatalytic–adsorptive removal of MB was observed.
• Removal rate of MB was 4 times better than P25TiO2 alone.
• Excellent reusability with sustainable rate of removal of MB.
• Treated water can be discharged directly without the need of a filtration system.

A bilayer immobilized system consisting of a mesoporous montmorillonite (MT) as the sublayer and a porous P25TiO2 toplayer was successfully fabricated on a glass plate. The MT sublayer was immobilized onto the glass plate by means of a glutaraldehyde (GLA) cross-linked poly (vinyl) alcohol (PVA) as the binder (MT-PVAB) while the top layer constituted of nano-sized TiO2 bound by the ENR-PVC polymer blends (P-25TiO2). The incorporation of MT-PVAB to P-25TiO2 caused a reduction in the band gap energy while PLS emission spectra suggested higher separation rate for the photo-generated electron–hole pairs in the P-25TiO2/MT-PVAB/GP. The photocatalytic–adsorption removal experiments showed that the P-25TiO2/MT-PVAB/GP enhanced removal rate of MB by an average of 4 times as compared with the immobilized monolayer P-25TiO2 on a glass plate (P-25TiO2/GP).

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