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Effects of quenching methods on HAA determination in chloraminated waters
This study examined the effects of using ammonium chloride (NH4Cl), a chlorine quenching agent recommended by US Environmental Protection Agency method 552.3, on haloacetic acid (HAA) determination under different chloramination scenarios simulated in laboratory experiments. During the early reaction times for the surface water tested in this study (dissolved organic carbon of 3 mg/L), results showed that HAA concentration was overestimated up to 9 μg/L because of the use of NH4Cl. In all chloramination scenarios, positive errors decreased with increasing reaction time. Among the various quenching agents or methods tested, sodium arsenite (NaAsO2) and stoichiometric amounts of sodium sulfite (Na2SO3) were found to be appropriate for HAA determination in chloraminated samples. However, they have some limitations for use in practical applications. Immediate extraction of samples without using any quenching agent resulted in positive errors in HAA determination because of the low pH conditions (pH < 1) coupled with high temperature after the addition of sulfuric acid during HAA extraction. Adjusting sample pH to high values and using ascorbic acid for quenching chloramine were found to be unsuitable for HAA samples.
Effects of quenching methods on HAA determination in chloraminated waters
This study examined the effects of using ammonium chloride (NH4Cl), a chlorine quenching agent recommended by US Environmental Protection Agency method 552.3, on haloacetic acid (HAA) determination under different chloramination scenarios simulated in laboratory experiments. During the early reaction times for the surface water tested in this study (dissolved organic carbon of 3 mg/L), results showed that HAA concentration was overestimated up to 9 μg/L because of the use of NH4Cl. In all chloramination scenarios, positive errors decreased with increasing reaction time. Among the various quenching agents or methods tested, sodium arsenite (NaAsO2) and stoichiometric amounts of sodium sulfite (Na2SO3) were found to be appropriate for HAA determination in chloraminated samples. However, they have some limitations for use in practical applications. Immediate extraction of samples without using any quenching agent resulted in positive errors in HAA determination because of the low pH conditions (pH < 1) coupled with high temperature after the addition of sulfuric acid during HAA extraction. Adjusting sample pH to high values and using ascorbic acid for quenching chloramine were found to be unsuitable for HAA samples.
Effects of quenching methods on HAA determination in chloraminated waters
Hong, Ying (author) / Liu, Suibing (author) / Song, Hocheol (author) / Hu, Jia (author) / Ates, Nuray (author) / Karanfil, Tanju (author)
Journal ‐ American Water Works Association ; 100 ; 89-99
2008-02-01
11 pages
Article (Journal)
Electronic Resource
English
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