Highly Transparent Poly(vinyl alcohol)(PVA)/TiO₂ Nanocomposite Films with Remarkable Photocatalytic Performance and Recyclability

Abstract

Titanium dioxide (TiO2) has been regarded as an efficient photocatalyst for degradation of environmental pollutants. However, recovery of TiO2 nanoparticles from suspension limits its practical application. Herein, we reported a novel highly transparent poly(vinyl alcohol)(PVA)/TiO2 photocatalytic film via in-situ growth and solution casting method. TiO2 nanoparticles with average size of 10 nm were uniformly dispersed in transparent PVA matrix. The photocatalytic performance was investigated by photodegradation of methyl orange (MO) aqueous solution under solar light irradiation. PVA/TiO2 photocatalytic film exhibited remarkably high photocatalytic activity and excellent recyclable properties during multi-cycle use. PVA not only acted as a transparent supports for TiO2, but also worked as an efficient holes scavenger. The hydroxyl groups on PVA chains played a key role in separation of photo-generated electrons and holes, thus increased the photodegradation rate of MO. This work gives an easy and reliable way for polymer/TiO2 nanocomposites in practical environmental applications.

An Overview of Polymer-Supported Catalysts for Wastewater Treatment through Light-Driven Processes

“…Additionally, the swelling ability of crosslinked PVA obtained by chemical or physical crosslinking methods can ensure that the embedded photocatalyst nanoparticles are fully in contact with the pollutants [60]. In addition, (i) Lei et al [60] and Ghule et al [65] verified that the treated catalyst/PVA matrix exhibited higher efficiency than the untreated matrix, because the untreated one displayed many catalyst aggregates and a non-homogeneous dispersion; (ii) Yan et al [47] and Yan et al [48] found that the heat treatment yields a transparent film; (iii) Yan et al [47] and Song et al [79] found that treating the PVA extends the light absorption of TiO 2 to the visible light region, as far as 800 nm; (iv) Yan et al [47], Wang et al [54], and Ren et al [68] reported that heat treatment improves the stability of the materials, which could be reused 5-8 times without efficiency loss. Furthermore, Lei et al [60] reused the materials for 25 cycles without a loss of efficiency.…”

“…In this process, the dispersion of nanoparticles in the polymer matrix is a critical issue in the successful preparation of transparent hybrid nanocomposites; therefore, after mixing, sonication methods are applied to disperse the particles [46]. The hydrothermal process is similar, because it involves mixing of the polymer and the catalyst, but it is performed at high temperatures [47,48].…”

“…Furthermore, Lei et al [60] reused the materials for 25 cycles without a loss of efficiency. However, some attention must be given to the treatment temperature, because it controls the crystallinity degree of the material, and can cause PVA degradation, change its swelling degree, and alter the surface area [47,48,54,60]. The conditions tested in the aforementioned studies and the results are presented in Table 11.…”

Novel PVA nanocomposite films: Synthesis, structure, optical and photocatalytic properties evaluation.

“…Researchers reported that some of the nanofiller doped PVA composites, and biopolymer blend PVA showed efficient removal of MB dye [29][30][31][32]. researchers also have reported that nanofiller and biomolecule doped PVA composites show excellent optical properties [33,34].…”

Synthesis and Physicochemical Properties of Poly(vinyl) Alcohol Nanocomposites Reinforced with Nanocrystalline Cellulose from Tea (Camellia sinensis) Waste

“…Incorporating some nano-sized fillers can improve the composite properties required for many industrial and technological applications. Polymer nanocomposite films with inorganic fillers can improve stiffness, strength, hardness, and high temperature creep resistance compared to unfilled polymers [ 1 , 2 , 3 ]. These nanocomposite films have recently become an issue of great concern from an economic, environmental, and performance point of view.…”