Rapid Removal and Mineralization of Bisphenol A by Heterosupramolecular Plasmonic Photocatalyst Consisting of Gold Nanoparticle-Loaded Titanium(IV) Oxide and Surfactant Admicelle.

Abstract

The establishment of technology for rapid and complete removal and mineralization of harmful phenolic compounds from water is of great importance for environmental conservation. Visible-light irradiation (λ > 430 nm, light intensity integrated from 420 to 485 nm = 6.0 mW cm-2) of Au nanoparticle (NP)-loaded TiO2 (Au/TiO2) in dilute aqueous solutions of bisphenol A (BPA) and p-cresol (PC) causes degradation of the phenols. The addition of trimethylstearylammonium chloride (C18TAC) enhances the adsorption of BPA on Au/TiO2 to greatly increase the rate of reaction. Consequently, 10 μM phenols are completely removed from the solutions within 2.5 h irradiation, and prolonging irradiation time to 24 h quantitatively oxidizes BPA to CO2. Dynamic light scattering ζ-potential measurements indicate that a C18TAC bilayer or admicelle is formed on the Au/TiO2 particle surface at C18TAC concentration >50 μM. The action spectrum for reaction shows that this reaction is driven by the Au NP localized surface plasmon resonance excitation-induced interfacial electron transfer from Au to TiO2. We propose a possible reaction scheme on the basis of the experimental results including intermediate analysis.