Ag@MnxOy: an effective catalyst for photo-degradation of rhodamine B dye

• Published in: Environmental chemistry letters Vol. 16; no. 1; pp. 287 - 294
• Main Authors: Saeed, Muhammad, Ahmad, Aziz, Boddula, Rajender, Inamuddin, Haq, Atta ul, Azhar, Aisha
• Format: Journal Article
• Language: English
• Published: Cham Springer International Publishing 01-03-2018; Springer Nature B.V
• Subjects: Ammonia; Analytical Chemistry; Analytical methods; Biodegradation; Catalysis; Catalysts; Catalytic activity; Degradation; Doping; Dyes; Earth and Environmental Science; Ecotoxicology; Effluents; Electron microscopy; Environment; Environmental Chemistry; Fourier transforms; Geochemistry; Heavy metals; Industrial effluents; Industrial pollution; Industrial wastes; Industrial wastewater; Infrared spectroscopy; Irradiation; Light irradiation; Manganese; Manganese oxides; Metal oxides; Metals; Original Paper; Oxides; Photodegradation; Plant extracts; Pollution; Pollution abatement; Recombination; Rhodamine; Scanning electron microscopy; Silver; Textile industry; Water pollution; Degradation; Mn; Eley–Rideal mechanism; Ag@Mn; Rhodamine B; Kinetics analysis; Activation energy; O
• ISSN: 1610-3653; 1610-3661
• DOI: 10.1007/s10311-017-0661-z

Water pollution by the textile industry is a major issue. Therefore, there is a need for methods to remove organic dyes from industrial effluents. Various metal oxides have been used as catalysts for the degradation of dyes. The catalytic efficiency of metal oxides can be enhanced by doping metal oxides with metals. Here we report the synthesis and characterization of nano-sized mixed valence manganese oxide (Mn
x
O
y
) and silver-doped mixed valence manganese oxide (Ag@Mn
x
O
y
). We study their photo-catalytic efficiency for the photo-degradation of the rhodamine B dye under light irradiation. Mn
x
O
y
was prepared using KMnO
4
, MnSO
4
and NH
3
, and Ag@Mn
x
O
y
was prepared using AgNO
3
and
Calotropis gigantea
plant extract. The prepared materials were characterized by X-ray diffractometry, scanning electron microscopy and Fourier transform infrared spectroscopy. Results show that doping with Ag enhanced the photo-catalytic performance of Mn
x
O
y
from 11 to 28% and 45 to 91% degradation of rhodamine B dye in 15 and 120 min, respectively. This enhancement is explained by the fact that Ag doping prevents the recombination of photoexcited electrons and positive holes, thus enhancing the photo-catalytic activity of Mn
x
O
y
.