Synthesis of Ag-coated on a wrinkled SiO2@TiO2 architectural photocatalyst: New method of wrinkled shell for use of semiconductors in the visible light range and penicillin antibiotic degradation

Abstract

In this study, a facile, environmentally friendly, room-temperature synthesis of Ag-coated on microporous TiO2-based catalysts and their application as a photocatalyst to degradation of penicillin as an antibiotic from pharmaceutical wastewater was investigated. The sol-gel method was used for the preparation of SiO2 and SiO2@TiO2. Then, the SiO2@TiO2 was wrinkled using hydrothermal treatment. Finally, Ag as plasmonic material was doped on wrinkled photocatalyst via wet chemistry approach. The synthesised photocatalysts were characterized using different analyses such as XRD, FTIR, RAMAN, FESEM, TEM, XPS. The results showed that the Ag was successfully coated on the wrinkled TiO2 layer. The performance of the synthesised photocatalyst was studied in terms of penicillin antibiotic removal from pharmaceutical wastewater in the range of visible light. The band gap energy (Eg) of SiO2 and after addition of TiO2 and Ag was obtained 4.5 and 2.8–3.2 eV. Specific surface of SiO2 and SiO2@WS-TiO2 was found 293 and 329 m2/g respectively. The results indicated that wrinkling and coating Ag can enhance the SiO2@TiO2 photocatalyst activity for degradation of penicillin. Furthermore, the operating parameter of degradation of penicillin such pH, contact time, initial penicillin concentration, temperature, and the amount of synthesized photocatalyst was optimized. Finally, it was found that Langmuir isotherm model is well fitted with experimental data to predict kinetic of penicillin degradation.

Keywords

• Pharmaceutical wastewater
• Photocatalyst
• Penicillin
• Nanoparticles
• Core@ wrinkled shell