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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