Premium
Efficient Dye Degradation Catalyzed by Manganese Oxide Nanoparticles and the Role of Cation Valence
Author(s) -
Debnath Bharati,
Roy Anupam Singha,
Kapri Sutanu,
Bhattacharyya Sayan
Publication year - 2016
Publication title -
chemistryselect
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.437
H-Index - 34
ISSN - 2365-6549
DOI - 10.1002/slct.201600806
Subject(s) - valence (chemistry) , manganese oxide , manganese , nanoparticle , catalysis , degradation (telecommunications) , chemistry , inorganic chemistry , materials science , chemical engineering , photochemistry , nanotechnology , computer science , organic chemistry , telecommunications , engineering
The ménage of 20–35 nm manganese oxide (Mn−O) nanoparticles (NPs) namely MnO, α‐Mn 2 O 3 , Mn 3 O 4 and δ‐MnO 2 have been employed as highly recyclable heterogeneous Fenton catalysts for organic dye degradation in wastewater treatment. Mn 3 O 4 was found to be superior to MnO, α‐Mn 2 O 3 and δ‐MnO 2 in the descending order under similar reaction conditions. The availability of active sites proportionate with the specific surface area could not interpret the relative performance since the specific surface area of MnO, α‐Mn 2 O 3 , Mn 3 O 4 and δ‐MnO 2 NPs were 71(±4), 16(±5), 63(±2) and 165(±5) m 2 /g, respectively. In fact, the presence of unpaired e g electrons in both Mn 2+ and Mn 3+ ions in Mn−O was found to be crucial for effective electron transfer to H 2 O 2 for the generation of intermediate radicals.The best MB degradation activity of 99.3(±2)% was observed with 100 mg/L 15–20 nm Mn 3 O 4 particles and 0.25 mol/L H 2 O 2 at 80°C within 60 min. The mechanism of the degradation process follows first‐order kinetics and is dependent on the generation of • OH radicals at the initial stage and 1 O 2 radicals after 30 min.