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Photocatalytic Degradation of Organic Reactive Dyes over MnTiO 3 /TiO 2 Heterojunction Composites Under UV ‐Visible Irradiation
Author(s) -
Sivakumar Santhanam,
Selvaraj Ayyasamy,
Ramasamy Anaipalayam Kandasamy
Publication year - 2013
Publication title -
photochemistry and photobiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.818
H-Index - 131
eISSN - 1751-1097
pISSN - 0031-8655
DOI - 10.1111/php.12136
Subject(s) - photocatalysis , heterojunction , materials science , scanning electron microscope , visible spectrum , degradation (telecommunications) , peroxydisulfate , hydrogen peroxide , photochemistry , composite material , chemistry , catalysis , organic chemistry , optoelectronics , metallurgy , telecommunications , potassium , computer science
In this study, the photocatalytic degradation of organic reactive dyes have been investigated using MnTiO 3 / TiO 2 heterojunction composites in the presence of electron acceptors under UV ‐Visible light irradiation. This MnTiO 3 / TiO 2 heterojunction composites were prepared by annealing different mass ratios of pyrophanite MnTiO 3 (3–11 wt%) and TiO 2 at 300°C. All the MnTiO 3 / TiO 2 heterojunction composites were characterized by spectral techniques like X ‐ray diffraction ( XRD ), scanning electron microscope ( SEM ) and diffused reflectance UV ‐visible spectroscopic analysis ( DRS ). Among them, 9 wt% MnTiO 3 / TiO 2 heterojunction composites exhibited higher photocatalytic activity for the degradation of Reactive Blue 4 ( RB 4). The photocatalytic efficiency of 9 wt% MnTiO 3 / TiO 2 heterojunction composites was further enhanced by the addition of substantial amount of electron acceptors like hydrogen peroxide ( H 2 O 2 ) and ammonium peroxydisulfate ([ NH 4 ] 2 S 2 O 8 ). The presence of oxidants (electron acceptors) facilitates the fast degradation of dye solution even in higher concentration upto 200 mg/L. The photocatalytic activity of MnTiO 3 / TiO 2 heterojunction composites was also studied for the degradation of other four different structured reactive dyes. The extent of mineralization of these organic reactive dyes during photocatalytic degradation was estimated from COD analysis. MnTiO 3 / TiO 2 heterojunction composites was also found to have good photostability in the presence of oxidants.