Kinetics of the Photocatalytic Decomposition of Bisphenol A on Modified Photocatalysts

Abstract

This paper presents the evaluation of the photocatalytic kinetics of bisphenol A decomposition in the presence of commercial titanium(IV) oxide and modified photocatalysts (composites). The following modification methods were used: mechanical mixing, calcination and impregnation. The decomposition process was carried out with the addition of photocatalysts and activated carbon at doses of 100 mg/dm3 and 25 mg/dm3, respectively. The photocatalytic process was performed in a reactor from the Heraeus Company (Warsaw, Poland) with a volume of 0.7 dm3. The reactor was equipped with an immersed medium-pressure mercury lamp with a power of 150 W (λ = 200–580 nm). The degree of bisphenol A decomposition was determined by chromatographic analysis preceded by solid-phase extraction SPE. The qualitative-quantitative analysis was performed using a high-performance liquid chromatograph HPLC (UV detector, λ = 218 nm) from Varian (Warsaw, Poland). The dependence of the BPA decomposition on the duration of irradiation was found, wherein the modified photocatalysts were the most effective (from 75 to 90% after 15 minutes). The order of photocatalyst efficiency has been proposed as follows: TiO2 < TiO2/AC < Cdextran-TiO2/AC < Cmethanol-TiO2/AC< Cethanol-TiO2/AC < TiO2-AC. The highest degree of decomposition was observed in the presence of TiO2/AC (99%). Numerous studies suggest that the results of the TiO2 photocatalytic oxidation of organic substances fit well with the Langmuir–Hinshelwood (L–H) kinetic model. The kinetic parameters of the photocatalysis process were carried out according to the L-H model. According to the pseudo-first-order parameters, the results showed that the decomposition of bisphenol A was most intensive in the first 15 minutes of the process.

Keywords

• kinetics
• photocatalysis
• modified photocatalysts
• bisphenol A