Degradation Investigation of Selected Taste and Odor Compounds by a UV/Chlorine Advanced Oxidation Process.
Taste- and odor-causing (T&amp;O) compounds are a major concern in drinking water treatment plants due to their negative impacts on the safety and palatability of water supply. This study explored the degradation kinetics and radical chemistry of four often-detected T&amp;O compounds, geosmin (GSM), 2-methylisoborneol (MIB), benzothiazole (BT), and 2-isobutyl-3-methoxypyrazine (IBMP), in the ultraviolet/chlorine (UV/chlorine) advanced oxidation process. All experiments were carried out in a 700 mL photoreactor and the process effectively degraded the investigated T&amp;O compounds in a slightly acidic environment. The degradation of T&amp;O decreased with increasing pH but slightly with decreasing chlorine dosage. When the pH increased from 6 to 8, the pseudo-first-order rate constants of GSM, MIB, BT, and IBMP dropped from 2.84 × 10-3, 2.29 × 10-3, 3.64 × 10-3, and 2.76 × 10-3 s-1 to 3.77 × 10-4, 2.64 × 10-4, 6.48 × 10-4, and 6.40 × 10-4 s-1, respectively. Increasing the chlorine dosage slightly accelerated the degradation of the investigated T&amp;O compounds, but excessive hypochlorous acid and hypochlorite scavenged the HO• radicals and reactive chlorine species (RCS). Generally, HO• primarily contributed to the degradation of all of the investigated T&amp;O compounds as compared to RCS. The degradation by RCS was found to be structurally selective. RCS could not degrade GSM, but contributed to the degradation of MIB, BT, and IBMP. The results confirmed that the proposed oxidation process effectively degraded typical T&amp;O compounds in aqueous phase.
['Fang|Jingyun|J|', 'Liu|Jiajian|J|', 'Shang|Chii|C|', 'Fan|Chihhao|C|']
D001892:Camphanes D002713:Chlorine D007700:Kinetics D009812:Odorants D010084:Oxidation-Reduction D013649:Taste D014466:Ultraviolet Rays D014874:Water Pollutants, Chemical D018508:Water Purification
taste and odor compounds UV/chlorine advanced oxidation process water treatment chlorine radical hydroxyl radical