Photocatalytic Degradation of Polystyrene Plastic under Fluorescent Light

Abstract

Plastic is used widely all over the world, due to the fact that it is low cost, is easily processable, and has lightweight properties. However, the hazard of discarding waste plastic, so-called "white pollution", is becoming more and more severe. In this paper, solid-phase photocatalytic degradation of polystyrene (PS) plastic, one of the most common commercial plastics, over copper phthalocyanine (CuPc) sensitized TiO2 photocatalyst (TiO2/CuPc) has been investigated under fluorescent light irradiation in the air. UV-vis spectra show that TiO2/CuPc extends its photoresponse range to visible light, contrasting to only UV light absorption of pure TiO2. The PS photodegradation experiments exhibit that higher PS weight loss rate, lower PS average molecular weight, less amount of volatile organic compounds, and more CO2 can be obtained in the system of PS-(TiO2/CuPc), in comparison with the PS-TiO2 system. Therefore, PS photodegradation over TiO2 CuPc composite is more complete and efficient than over pure TiO2, suggesting the potential application of dye-sensitized TiO2 catalyst in the thorough photodegradation of PS plastic under fluorescent light. During the photodegradation of PS plastic, the reactive oxygen species generated on TiO2 or TiO2/CuPc particle surfaces play important roles in chain scission. The present study demonstrates that the combination of polymer plastic with dye-sensitized TiO2 catalyst in the form of thin film is a practical and useful way to photodegrade plastic contaminants in the sunlight.

Photocatalytic Activities of TiO2 Modified by Poly(fluorene- co-bithiophene) under Visible Light

“…It showed that little phenol was decomposed with pure TiO 2 under visible light, while with PFB/TiO 2 nearly 75% of the phenol was removed. It is suggested that PFB is an effective photosensitizer, as has been reported for some dyes [9][10][11]. Kinetically, the degradation reaction showed the firs-order behavior.…”

“…This indicated that interactions between TiO 2 and PFB were responsible for the photocatalytic degradation, because neither TiO 2 nor PFB alone is effective. It is generally believed [10,11] that upon visible light irradiation, the photosensitizer adsorbed onto the surface of TiO 2 gets excited and injects an electron into the conduction band of TiO 2 . This conduction band electron is subsequently captured by dioxygen adsorbed onto the surface of TiO 2 and induces the generation of ·O 2 -/HO· radicals which attack organic pollutants to yield the ultimate products.…”

“…The electrons transferred from PFB to TiO 2 , and holes (h + ) transferred from TiO 2 into valence band of PFB [11]: TiO 2 + hυ → TiO 2 (e -+ h + )…”

“…Recently many studies have been devoted to improving photocatalytic activity under the visible light by surface modifying TiO 2 using dyes. Great success was achieved in the field of dye-sensitized solar cell [7,8] as well as the dye-sensitized TiO 2 for photocatalytic degradation of the organic pollutions [9][10][11]. Three basic processes are involved in the dye sensitizing semiconductor.…”

Photocatalytic degradation of polypropylene/TiO2 nano-composites

“…Therefore, it seems that the composition of plastic with TiO 2 nanoparticles is a useful means to decompose solid polymer in the open air. Researchers have recently studied the solid-phase photocatalytic degradation of polymer-TiO 2 nano-composite [8][9][10][11][12] . But the photodegradation properties of PP nano-composites has rarely been studied.…”