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3703204 
Journal Article 
Comparing the suitability of sodium hyposulfite, hydroxylamine hydrochloride and sodium sulfite as the quenching agents for permanganate oxidation 
Sun, Bo; Rao, D; Dong, H; Guan, X 
2016 
1 
RSC Advances
EISSN: 2046-2069 
6 
16 
13335-13342 
WOS:000369546100067 
An appropriate quenching agent for potassium permanganate (KMnO4) is necessary for investigating the oxidation kinetics of contaminants by KMnO4. In this paper, the suitability of three most commonly used inorganic reductants, including sodium hyposulfite (Na2S2O3), hydroxylamine hydrochloride (NH2OH center dot HCl) and sodium sulfite (Na2SO3), for quenching KMnO4 was systematically investigated with phenol as a probe contaminant. Na2S2O3 applied with Na2S2O3/KMnO4 molar ratio of 20.0 was a good choice for quenching KMnO4 over the pH range of 2.0-11.0. Quenching KMnO4 with NH2OH center dot HCl was a good alternative with 20-fold excess at pH 4.0-9.0. However, Na2SO3 was not recommended to be the quenching agent of KMnO4 due to the significant change of phenol concentration during quenching reaction. The 3-dimensional UV-vis spectra at different pH were collected with stopped flow spectrometer to investigate the quenching mechanisms of these three quenchers toward KMnO4, which clearly showed the variation of manganese species with time.