[Influence of Chemical Pre-oxidation on Chloral Hydrate Formation of Threonine].

The influences of different chemical pre-oxidants, including sodium hypochlorite (NaClO), chlorine dioxide (ClO), permanganate (KMnO), hydrogen peroxide (HO), ozone (O) and ozone/hydrogen peroxide (O/HO), on chloral hydrate (CH) formation were studied for threonine that has the highest special chloral hydrate formation potential (SCHFP). Suitable pre-oxidants and corresponding optimal doses were determined to provide guidance for controlling chloral hydrate (CH) formation during drinking water treatment. The results indicated that the pre-oxidants that could decrease CH formation for one day incubation time (CH) were HO, ClO, KMnO and NaClO, and the corresponding suitable doses were 3, 0.5, 0.6 and 0.5 mg·L, and the corresponding CH removal rates were 61.54%, 47.63%, 29.77% and 10.94%, respectively. The pre-oxidants that could decrease CH formation potential (CHFP) were KMnO, NaClO, HO and ClO, and the corresponding suitable doses were 0.6 mg·L, 0.5 mg·L, 3 mg·L and 0.5 mg·L, and the corresponding CHFP removal rates were 41.01%, 33.38%, 8.36% and 2.40%, respectively. In addition, O and O/HO were not suitable for controlling CH in the conventional treatment process because they could increase CH and CHFP.