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Degradation of Nile blue sulphate dye onto iron oxide nanoparticles: Kinetic study, identification of reaction intermediates, and proposed mechanistic pathways
Author(s) -
Kushwaha Rajkamal,
Garg Sangeeta,
Bajpai Shailendra,
Giri Ardhendu Sekhar
Publication year - 2018
Publication title -
asia‐pacific journal of chemical engineering
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.348
H-Index - 35
eISSN - 1932-2143
pISSN - 1932-2135
DOI - 10.1002/apj.2200
Subject(s) - chemistry , analytical chemistry (journal) , fourier transform infrared spectroscopy , activation energy , reaction rate constant , arrhenius plot , maghemite , nuclear chemistry , absorbance , desorption , adsorption , kinetics , mineralogy , organic chemistry , chromatography , chemical engineering , physics , hematite , quantum mechanics , engineering
Iron oxide nanoparticles (Fe 3 O 4 NPs) were synthesized and characterized using Fourier transform infrared spectroscopy, X‐ray diffraction, vibrating sample magnetometer, nitrogen adsorption–desorption, and transmission electron microscopy. Vibrating sample magnetometer analysis confirmed the superparamagnetic behavior of Fe 3 O 4 NPs with a specific saturation magnetization value 43 emu g −1 . Synthesized Fe 3 O 4 NPs exhibited surface area 52 m 2 g −1 with pore volume 0.0729 cc g −1 and average pore diameter 5.528 nm. The degradation efficiency of Nile blue sulphate (NBS) dye onto Fe 3 O 4 NPs was 86.8% with total organic carbon removal and chemical oxygen demand conversion of 65.6% and 55.9%, respectively, at 5mM H 2 O 2 and 50 mg l −1 of NBS dye concentration for 12 min of reaction time. Rate of degradation of dye onto Fe 3 O 4 NPs followed second‐order kinetic rate equation with high value of regression coefficient (R 2 = 0.997) at 303 K. The low activation energy (19.16 kJ mol −1 ) obtained from Arrhenius plot showed that of Fe 3 O 4 NPs have high catalytic activity towards the degradation of NBS dye during oxidation process. The intermediate products formed during degradation of NBS dye were detected by liquid chromatography–mass spectrometry experiment, and 11 numbers of fragments were detected on the basis of mass to charge ratio (m/z) at 24.186 min. The degradation of NBS dye was attributed to formation of intermediates from destruction of conjugated structure of dye and transformation of these intermediates into small molecules, which were further mineralized to water and carbon dioxide.