Coelho Alessandra D, Sans Carmen, Agüera Ana, Gómez Maria José, Esplugas Santiago, Dezotti Márcia
Programa de Engenharia Química - COPPE, UFRJ, CP 68502, 21941-972, Rio de Janeiro, Brazil.
Sci Total Environ. 2009 May 15;407(11):3572-8. doi: 10.1016/j.scitotenv.2009.01.013. Epub 2009 Feb 26.
Diclofenac (DCF), a common analgesic, anti-arthritic and anti-rheumatic drug, is one of the most frequently detected compounds in water. This study deals with the degradation of diclofenac in aqueous solution by ozonation. Biodegradability (BOD(5)/COD ratio and Zahn-Wellens test), acute ecotoxicity and inhibition of activated sludge activity were determined in ozonated and non-ozonated samples. Liquid chromatography coupled with time-of-flight mass spectrometry (LC/TOF-MS) was used to identify the intermediates formed in 1 h of ozonation. Eighteen intermediates were identified by these techniques and a tentative degradation pathway for DCF ozonation is proposed. Experimental results show that ozone is efficient at removing DCF: >99% removal (starting from an initial concentration of 0.68 mmol L(-1)) was achieved after 30 min of ozonation (corresponding to an absorbed ozone dose of 0.22 g L(-1), which is 4.58 mmol L(-1)). However, only 24% of the substrate was mineralized after 1 h of ozonation. The biodegradability, respiration inhibition in activated sludge and acute toxicity tests demonstrate that ozonation promotes a more biocompatible effluent of waters containing DCF.
双氯芬酸（DCF）是一种常见的止痛、抗关节炎和抗风湿药物，是水中最常检测到的化合物之一。本研究探讨了臭氧氧化法降解水溶液中的双氯芬酸。对臭氧氧化和未臭氧氧化的样品测定了生物降解性（五日生化需氧量/化学需氧量比值和赞恩-韦伦斯试验）、急性生态毒性和活性污泥活性抑制情况。采用液相色谱-飞行时间质谱联用（LC/TOF-MS）技术鉴定臭氧氧化1小时形成的中间体。通过这些技术鉴定出18种中间体，并提出了双氯芬酸臭氧氧化的初步降解途径。实验结果表明，臭氧能有效去除双氯芬酸：臭氧氧化30分钟后（对应吸收臭氧剂量为0.22 g L-1，即4.58 mmol L-1），去除率>99%（初始浓度为0.68 mmol L-1）。然而，臭氧氧化1小时后，只有24%的底物被矿化。生物降解性、活性污泥中的呼吸抑制和急性毒性试验表明，臭氧氧化可使含双氯芬酸的水产生更具生物相容性的流出物。
