Poly(vinyl alcohol) Embedded with Montmorillonite Clay and Nano Titania: A Scale-Up for Sustainable Environmental Remediation

Abstract

A poly(vinyl alcohol)/montmorillonite/titania (PVA/MMT/TiO 2 ) nanocomposite film was fabricated via a simple solution casting strategy for the removal of cationic as well as anionic dyes. The developed nanocomposite film was subjected to X-ray diffraction (XRD), Fourier transform Infrared (FTIR), thermogravimetric analysis, dynamic mechanical analysis (DMA), mechanical property evaluation, and scanning electron microscopy (SEM) analysis. The embedding of MMT and TiO 2 nanoparticles onto a PVA matrix has been confirmed from XRD, FTIR, and SEM analysis. It has been found that the thermal and mechanical properties of virgin PVA have been significantly improved by embedding it with MMT and TiO 2 . The embedded system also exhibited excellent room-temperature storage modulus compared to the unfilled system, as revealed from DMA. By utilizing the adsorption characteristics of MMT and photocatalytic activity of TiO 2 , the developed PVA/MMT/TiO 2 nanocomposite film was used for the removal of model dyes, viz, malachite green (MG), methylene blue (MB), and cotton blue (CB). The highest removal efficiency for cationic MG and MB was 99.99% and 99.79%, respectively, for 15 min of exposure time. The anionic CB showed a removal efficiency of 98.52%. The highlight of the work is that, since the adsorbent and photocatalyst are embedded onto a polymer matrix and made in the form of a film, we can easily recover the film from the solution after use, with no need of centrifugation and further purification strategies as in the case of powderous photocatalysts. Further, the PVA/MMT/TiO 2 nanocomposite film exhibited excellent reusability of 10 cycles, which is a very high value in comparison with literature reports.