Ag-loaded ZnO materials for photocatalytic water treatment

• Type: Article in International Scientific Journal
• Date: 2017

Authors

Sampaio, M.J. (Author) FEUP; Maria Lima (Author) Other; Baptista, DL (Author) Other; Silva, Adrian (Author) FEUP; Claudia G Silva (Author) FEUP; Joaquim Luís Faria (Author) FEUP

Journal

Title: Chemical Engineering Journal

Vol. 318

Pages: 95-102

ISSN: 1385-8947

Publisher: Elsevier

Indexing

ISI Web of Knowledge - 33 Citations

Scopus - 68 Citations

Other information

Authenticus ID: P-00R-CK4

DOI: 10.1016/j.cej.2016.05.105

Abstract (EN): ZnO materials with different morphologies were obtained by hydrothermal and solid state techniques. The ZnO materials were loaded with different amounts of silver nanoparticles (atomic percentages ranging from 0.25 to 1) by a liquid impregnation method. The materials were characterized by physical adsorption of nitrogen, scanning and high-resolution transmission electron microscopy (SEM, HRTEM), UV-vis diffuse reflectance spectroscopy (DRUV-Vis), X-ray photoelectron spectroscopy (XPS) and temperature programmed reduction (TPR). The photocatalytic efficiency of the materials was assessed in the degradation of phenol using simulated solar light, by means of the pseudo-first-order kinetic constant (k(app)) for phenol conversion and corresponding degree of mineralization. The photocatalyst made of ZnO prepared by thermal decomposition of zinc acetate (ZnO-t) loaded with a 0.25 atomic percentage of Ag (0.25%Ag/ZnO-t) was the most efficient, reaching a 58% mineralization after 60 min irradiation (k(app)=7.7 x 10(-2) min(-1)). Trapping of photogenerated holes and radicals by selective scavengers showed that photogenerated holes played the main role on phenol oxidation. The study was extended to a complex mixture containing phenol, resorcinol, 4-methoxyphenol and 4-chorophenol using bare ZnO-t and 0.25%Ag/ZnO-t photocatalysts, either in powder form or immobilized on glass rings (packed in a continuous photocatalytic reactor). The conversion of the phenolic compounds was faster when Ag particles were deposited on the photocatalyst.

Language: English

Type (Professor's evaluation): Scientific

No. of pages: 8