Degradation of organic pollutants in the presence of new Mn (II) complexes under ambient light or darkness conditions

• Published in: Journal of photochemistry and photobiology. A, Chemistry. Chemistry., 2023-08, Vol.442, p.114775, Article 114775
• Main Authors: Vallavoju, Rohini, Kore, Ranjith, P., Radhika, Subburu, Mahesh, Basude, Manohar, Chetti, Prabhakar, Pola, Someshwar
• Format: Article
• Language: English
• Subjects: Ambient Light catalysis; Cationic and Anionic dyes; Mn(II)-complexes; Rate of recombination; Surface area
• ISSN: 1010-6030; 1873-2666
• DOI: 10.1016/j.jphotochem.2023.114775

M−2 ([Mn(FPAMN)]) complex act as catalyst for mineralization of organic dye pollutants under room light or darkness conditions due to Mn (II) complexes bandgap energies fallen near IR region and high surface area then which supports to hydroxy radicals/holes formation and stable in HOMO of complex M−2. [Display omitted] •Synthesis of new Mn (II) complex using organic functional group-based salophen ligand which consists of N and O donor atoms for complexation.•Several spectroscopic methods are utilized for analysis new Mn(II)-complexes.•New Mn(II)-complexes act as catalysts for mineralization of organic dye contaminants under room light or darkness conditions.•The active species for the mineralization of organic dye contaminants is hydroxy radicals/holes from foragers tests. The Mn (II) complexes prepared from Schiff’s bases, like salophen type ligands, were complexed via N & O donors under the solvothermal method. These Mn (II) complexes were first validated through elemental data, which was confirmed by mass spectra. At the same time, several spectroscopic practices such as XPS, p-XRD, FT-IR, Raman, FESEM and thermal-stability of the Mn2+ complexes were examined from TGA. The bandgap energies and oxidation potentials of the Mn (II) complexes are assessed with UV–visible DRS and CV investigations. Emission spectra clearly stated that the rate of recombination electron and hole pair is lower for the M−2 complex as compared to the M−1complex. The prepared Mn (II) complexes were used for the mineralization of cationic and anionic dyes such as rhodamine 6G (Rh6G λmax. = 553 nm), and congo red (CR λmax. = 498 nm) under dark ambient conditions. The M−2 complex is more active than M−1 due to its low bandgap energy, low rate of recombination hole-electron pair, and insitu formation of superoxide radicals during catalytic dark ambient mineralization. Active species are identified by ESR studies, which are supported by scavenger data, and then the mechanism of the rapid mineralization of organic dye contaminants is established.