自由餘氯存在下之氯胺酮光降解

Sunlight Photodegradation of Ketamine in the Presence of Free Available Chlorine

王宥翔(Yu-Hsiang Wang)

指導教授 ： 林郁真

國立臺灣大學/工學院/環境工程學研究所/碩士(2015年)

https://doi.org/10.6342/NTU.2015.10756

摘要

無資料

關鍵字

自由餘氯 ； 藥物 ； 管制藥品 ； 氯胺酮 ； K它命 ； 光降解

並列摘要

Ketamine, along with many other pharmaceutical residues found in natural water environments pose potential risk to ecosystem and to public health. This work aimed to establish a kinetic model and to investigate the degradation mechanism of ketamine under solar irradiation in the presence of free available chlorines (FAC), namely FAC photolysis. To my knowledge, this is the first work identifying reactive species other than HO• and ozone during FAC photolysis, and the first effort to develop a kinetic model describing this phenomenon.

Compared with the chlorination and natural sunlight photolysis alone, FAC photolysis effectively enhanced the degradation efficiency of ketamine. FAC photolysis can be described with the shifting order-type kinetic, and the model combing two shifting order equations was developed to successfully predict the reaction rates for varying ketamine (25 - 500 μg/L) and FAC concentrations (0.05 - 3 mg Cl2/L) with 13% deviation from the real experimental values at pH 7.

HO• and ozone were found to be the dominant reactants in the presence of FAC; HO• contributed 69 to 83% of ketamine removal in initial 10 minutes of the FAC photolysis at pH 7. At lower pH (higher HOCl/ OCl−), more HO• and O3 were produced enhancing the reaction rates, and resulting in higher mineralization (67% of TOC removal at pH 4; 37% TOC removal at pH 10). Similar results were obtained with five other pharmaceuticals (atenolol, metoprolol, pentoxifylline, gemfibrozil and ibuprofen) investigated. Within 30 minutes of the reaction time, each compound was >90% removed.

As FAC residue decreased and entirely depleted, other reactive chlorine species (RCSs), were found to dominate the further ketamine removal at all pH values tested (pH 3-11), and this phenomena was compound dependent. It is hypothesized that these RCSs can react with primary, secondary amine and ether functional groups of ketamine, atenolol, metoprolol and gemfibrozil.

FAC photolysis transformation byproducts include DNK, HK, P2, P3, P4. Other byproducts including [M+H+] =216, 220, 258, 275, 326 and 345 were found during FAC photolysis. The rate and amount of these byproducts formed significantly depend on pH values and resulted in different toxicity. Compared with natural photolysis, FAC photolysis undergoes different degradation pathways, resulted in different byproducts (only P2, P3, HK, NK and DNK were found at both systems), different toxicity, and more mineralization. This phenomenon has the potential to be developed into an engineering system; however, the increase of toxicity needs to be evaluated and considered.

並列關鍵字

free available chlorine ； pharmaceutical ； illicit drug ； ketamine ； photodegradation

參考文獻

Ashitani, K., Y. Hishida and K. Fujiwara (1988). "BEHAVIOR OF MUSTY ODOROUS COMPOUNDS DURING THE PROCESS OF WATER TREATMENT " Water Science & Technology 20: 261-267.

Biedenkapp, D., L. G. Hartshorn and E. J. Bair (1970). "The O(1D) + H2O reaction." CHEMICAL PHYSJCS LETTERS 5: 379-381.

BUXTON, B. G. V. and M. S. SUBHANI (1972). "Radiation Chemistry and Photochemistry of Oxychlorine Ions Part 2.-Photodecomposition of Aqueous Solutions of Hypochlorite Ions." Journal of the Chemical Society, Faraday Transactions 1: Physical Chemistry in Condensed Phases 68: 958-969.

Buxton, G. V. and M. S. Subhani (1972). "Radiation chemistry and photochemistry of oxychlorine ions. Part 2.-Photodecomposition of aqueous solutions of hypochlorite ions." Journal of the Chemical Society, Faraday Transactions 1: Physical Chemistry in Condensed Phases 68(0): 958-969.

Fang, J., Y. Fu and C. Shang (2014). "The Roles of Reactive Species in Micropollutant Degradation in the UV/Free Chlorine System." Environmental Science & Technology 48: 1859-1868.