Premium
Monochloramination of Oxytetracycline: Kinetics, Mechanisms, Pathways, and Disinfection By‐Products Formation
Author(s) -
Bi Xiangyu,
Xu Bin,
Lin YiLi,
Hu ChenYan,
Ye Tao,
Qin Cao
Publication year - 2013
Publication title -
clean – soil, air, water
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.444
H-Index - 66
eISSN - 1863-0669
pISSN - 1863-0650
DOI - 10.1002/clen.201200344
Subject(s) - chemistry , kinetics , reaction rate constant , oxytetracycline , hydroxylation , chloroform , degradation (telecommunications) , medicinal chemistry , nuclear chemistry , chromatography , biochemistry , antibiotics , enzyme , telecommunications , physics , quantum mechanics , computer science
This study investigated the degradation kinetics, formation of disinfection by‐products (DBPs), and degradation pathways during monochloramination of oxytetracycline (OTC). The degradation kinetics can be well described by a second‐order kinetic model, first‐order in monochloramine (NH 2 Cl), and first‐order in OTC. Reaction of OTC with NH 2 Cl shows a high reactivity, with the apparent rate constant of 17.64/M/s at pH 7. The apparent rate constant declined as pH increased from 5 to 10. Six DBPs were detected during monochloramination of OTC, including chloroform (CF), 1,1‐dichloro‐2‐propanone (1,1‐DCP), 1,1,1‐trichloro‐2‐propanone (1,1,1‐TCP), dichloroacetonitrile (DCAN), trichloronitromethane (TCNM), and N ‐nitrosodimethlyamine (NDMA). CF, DCAN and NDMA had the maximum yields at neutral pH, while 1,1‐DCP and 1,1,1‐TCP had the maximum yields at pH 4. However, TCNM concentration increased as pH increased. Degradation pathways of OTC monochloramination were then proposed. Hydroxylation and Cl‐substitution are found to be the dominant mechanisms in monochloramination of OTC.