Disinfection By-Products Foramtion Potential of Twenty Amino Acids

DBPs formation potential, including THMs, HAAs, HKs, chloropicrin, and chloral hydrate, of 20 amino acids was evaluated. Chlorination experiments were carried out at pH=8.0±0.1 by using phosphates buffer and performed at Cl2:N=8:1(molar ratio) at 20±1° C for a reaction duration of 24h. Chlorination experiments shown the DBPs formation potential of 20 amino acids differed considerably and without any obvious relationship to TOC contents. THMs, HAAs, HANs, HKs, chloropicrin, and chloral hydrate formation potential were in the range of 0.001~0.467 mol/mol, 0~0.669 mol/mol, 0.005~1.170 mmol/mol, 0.031~9.270 mmol/mol, 0~1.380 mmol/mol, and 0.059~39.080 mmol/L, respectively. THMs and HAAs were two largest classes of DBPs formed which accounts for 61~99% of total DBPs detected in the experiments except for Glu(43%) and Ile(32%). However, unlike NOM and resorcinol, THMs and HAAs formation were not related which indicated that the THMs and HAAs formation paths were different as compared with NOM. Certain amount of N-DBPs were found, but the formation potential are relatively small when compared with THMs and HAAs.