Immobilization of nanomaterials in PMMA composites for photocatalytic removal of dyes, phenols and bacteria from water

• Freestanding TiO2-based nanocomposites realized with industrially scalable method.
• These nanocomposites are stable, harmless and cheap.
• These nanocomposites show significant photocatalytic and antibacterial activity.
• These nanocomposites are very active also under visible light.

Nanomaterials represent a possible solution to solve many of the current issues involving water quality, but several limitations exist for efficient applications, primarily concerning the dispersion of such nanomaterials in water, their recovery after water treatment and the resulting impact on human health and ecosystems. We present an approach based on the incorporation of several nanomaterials into polymeric composites as a valid solution to overcome these problems. We embedded active TiO2 nanostructures in poly (methyl methacrylate) (PMMA), with the advantage of no need of recovery of the nanoparticles after water treatment. Furthermore, we combined titanium dioxide nanoparticles with single walled carbon nanotubes, as acceptor of electrons, and obtained a significantly higher photocatalytic efficiency under UV irradiation, compared to the systems with TiO2 only. Photoactive materials even under visible light were synthesized thanks to the functionalization of the TiO2 nanoparticle surface with meso-tetraphenylporphyrin-4,4′,4′′,4′′′-tetracarboxylic acid (TCPP) as dye sensitizer. We realized these polymeric nanocomposites by low-cost solution casting and evaluated their photocatalytic activity by degradation of some dyes and phenol in an aqueous medium. A significant antibacterial activity, measured through CFU (colony forming units) count using Escherichia coli as a model organism, is also reported.

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